This document summarizes a study that found phosphatidylinositol-(3,4,5)-trisphosphate (PIP3) is continuously required to maintain AMPA receptor clustering at the postsynaptic membrane, which is necessary for sustaining synaptic function. The study manipulated PIP3 levels in hippocampal neurons and found that reducing PIP3 impaired the accumulation of PSD-95 in spines and caused AMPA receptors to become more mobile and migrate away from the postsynaptic density, leading to synaptic depression over time. Therefore, constant low-level turnover of PIP3 at synapses is required to maintain AMPA receptor clustering and synaptic strength under normal conditions.
mRNA stability and localization.RNA is critical at many stages of gene expression. How frequently it will be translated, how long it is likely to survive, and where in the cell it will be translated. RNA cis-elements & associated proteins
The document summarizes several key post-transcriptional processes involved in modifying mRNA in eukaryotes. These include 5' capping, 3' polyadenylation, intron removal through splicing, and the role of heterogeneous ribonucleoproteins (hnRNP) in transporting mRNA out of the nucleus. The splicing process involves small nuclear RNAs binding in a spliceosome to catalyze two transesterification reactions that remove introns and ligate exons. Mature mRNA can also be generated through trans-splicing of separate RNA molecules or alternative splicing of different exons from the same gene. Nuclear pore complexes selectively transport molecules including mRNA in and out of the nucleus.
Small interfering RNA (siRNA) are double stranded RNA molecules that are 20-25 base pairs in length and silence gene expression through RNA interference. Andrew Fire and Craig Mello discovered RNA interference in 1998 through experiments injecting double stranded RNA into nematode worms, finding it caused gene silencing. The mechanism involves dicer cleaving double stranded RNA into siRNAs which are then loaded into an RISC complex to bind and cleave target mRNAs, preventing protein synthesis from that gene. SiRNA has significance in protecting against viruses, regulating development, and suppressing transcription, and applications in research to determine protein function and potential clinical uses like cancer treatment.
Riboswitches are RNA elements found in the 5' untranslated region of mRNA that can bind to specific metabolites and undergo a conformational change to regulate gene expression. They are classified based on the ligand they bind and their secondary structure. Examples include TPP, lysine, glycine, FMN, purine, and cobalamin riboswitches. A riboswitch has two domains - an aptamer domain that binds the ligand and an expression platform domain that can adopt two structures to control transcription or translation. Binding of a metabolite can induce formation of a terminator stem loop to terminate transcription, mask the ribosome binding site to inhibit translation initiation, or trigger self-cleavage of the mRNA.
1. LncRNAs interact with chromatin and regulate gene expression through several mechanisms including chromatin regulation, protein-lncRNA localization and function on chromatin, and direct interactions between lncRNA and DNA.
2. LncRNAs can interact with chromatin through mechanisms like chromatin decompaction, altering the chromatin environment, and binding DNA directly or through protein interactions. This regulates gene expression in cis or trans.
3. Direct lncRNA-DNA interactions like triplex structures and R-loops also influence chromatin accessibility and gene expression by recruiting chromatin modifiers or transcription factors.
RNA processing is the modification of primary RNA transcripts into mature RNA molecules. It involves removal of introns through splicing and addition of modifications like 5' capping, 3' polyadenylation tail, and RNA editing. Alternative splicing allows a single gene to produce multiple protein isoforms by selective inclusion or exclusion of exons from the final mRNA.
mRNA stability and localization.RNA is critical at many stages of gene expression. How frequently it will be translated, how long it is likely to survive, and where in the cell it will be translated. RNA cis-elements & associated proteins
The document summarizes several key post-transcriptional processes involved in modifying mRNA in eukaryotes. These include 5' capping, 3' polyadenylation, intron removal through splicing, and the role of heterogeneous ribonucleoproteins (hnRNP) in transporting mRNA out of the nucleus. The splicing process involves small nuclear RNAs binding in a spliceosome to catalyze two transesterification reactions that remove introns and ligate exons. Mature mRNA can also be generated through trans-splicing of separate RNA molecules or alternative splicing of different exons from the same gene. Nuclear pore complexes selectively transport molecules including mRNA in and out of the nucleus.
Small interfering RNA (siRNA) are double stranded RNA molecules that are 20-25 base pairs in length and silence gene expression through RNA interference. Andrew Fire and Craig Mello discovered RNA interference in 1998 through experiments injecting double stranded RNA into nematode worms, finding it caused gene silencing. The mechanism involves dicer cleaving double stranded RNA into siRNAs which are then loaded into an RISC complex to bind and cleave target mRNAs, preventing protein synthesis from that gene. SiRNA has significance in protecting against viruses, regulating development, and suppressing transcription, and applications in research to determine protein function and potential clinical uses like cancer treatment.
Riboswitches are RNA elements found in the 5' untranslated region of mRNA that can bind to specific metabolites and undergo a conformational change to regulate gene expression. They are classified based on the ligand they bind and their secondary structure. Examples include TPP, lysine, glycine, FMN, purine, and cobalamin riboswitches. A riboswitch has two domains - an aptamer domain that binds the ligand and an expression platform domain that can adopt two structures to control transcription or translation. Binding of a metabolite can induce formation of a terminator stem loop to terminate transcription, mask the ribosome binding site to inhibit translation initiation, or trigger self-cleavage of the mRNA.
1. LncRNAs interact with chromatin and regulate gene expression through several mechanisms including chromatin regulation, protein-lncRNA localization and function on chromatin, and direct interactions between lncRNA and DNA.
2. LncRNAs can interact with chromatin through mechanisms like chromatin decompaction, altering the chromatin environment, and binding DNA directly or through protein interactions. This regulates gene expression in cis or trans.
3. Direct lncRNA-DNA interactions like triplex structures and R-loops also influence chromatin accessibility and gene expression by recruiting chromatin modifiers or transcription factors.
RNA processing is the modification of primary RNA transcripts into mature RNA molecules. It involves removal of introns through splicing and addition of modifications like 5' capping, 3' polyadenylation tail, and RNA editing. Alternative splicing allows a single gene to produce multiple protein isoforms by selective inclusion or exclusion of exons from the final mRNA.
The document summarizes the process of translation, which involves mRNA being decoded by ribosomes to produce a specific amino acid sequence. It describes the three stages of translation - initiation, elongation, and termination. Key components like mRNA, ribosomes, tRNAs, and aminoacyl-tRNA synthetases are discussed. The roles of these components in reading the genetic code contained in mRNA and synthesizing polypeptide chains are explained over multiple paragraphs.
Long non coding RNA and Their clinical perspectiveMOHIT GOSWAMI
This document discusses long non-coding RNAs (lncRNAs), which are RNA molecules longer than 200 nucleotides that do not code for proteins but play important regulatory roles. It describes the central dogma of molecular biology and how most of the human genome is transcribed into non-coding RNA. It classifies lncRNAs and explains their potential functions as signals, decoys, guides and scaffolds. The document also discusses the roles of lncRNAs in several human diseases like cancer, Alzheimer's, diabetes and more. It concludes that lncRNAs are important biomarkers and therapeutic targets due to their involvement in complex disease pathogenesis.
Almost 98 of the human genome does not encode proteins
o The non coding transcripts less than 200 bases are called small non
coding RNA and comprise of tRNA, rRNA, miRNA, snoRNA, piwi
interacting RNA (pi RNA)
o RNA molecules that are of more than 200 bases in length are known
as long non coding RNA (
o lncRNAs are more than 200 nucleotides in length and also can be
more than 2 Kb
o Such long noncoding RNAs usually have limited coding potential due
to the absence of open reading frames, 3 UTR and termination
region while their coding potential is less than 100 amino acids
RNA exists in various forms that perform important cellular functions. The major types of RNA include messenger RNA (mRNA), which carries genetic information from DNA to direct protein synthesis, transfer RNA (tRNA) that transports amino acids, and ribosomal RNA (rRNA) which combines with proteins to form ribosomes and facilitate protein synthesis. Other RNAs include small nuclear RNAs that process mRNA, microRNAs and small interfering RNAs that regulate gene expression, and heterogeneous nuclear RNA that is processed into mRNA.
- mRNA carries genetic information from DNA to the ribosome where protein synthesis occurs. It is single-stranded and complementary to one DNA strand.
- rRNA makes up 80% of cellular RNA and is a component of ribosomes. rRNA molecules synthesized in the nucleolus combine with proteins to form ribosomes, the sites of protein synthesis.
- tRNA acts as an intermediary between mRNA and amino acids during protein synthesis. It has a cloverleaf secondary structure and binds to specific amino acids to deliver them to the ribosome based on the mRNA sequence.
This document summarizes various processes involved in RNA processing in eukaryotes. It discusses 5' capping and polyadenylation of pre-mRNA, as well as splicing of introns and exons. Splicing involves two transesterification reactions catalyzed by a spliceosome complex containing U1, U2, U4, U5 and U6 small nuclear ribonucleoproteins (snRNPs). Alternative splicing and RNA editing are also described, where editing can involve base modification or insertion/deletion of nucleotides guided by small RNAs.
Prokaryotic and eukaryotic transcription differ in several key ways. Prokaryotic transcription occurs in the cytoplasm and uses a single RNA polymerase to produce polycistronic mRNA, while eukaryotic transcription takes place in the nucleus using three RNA polymerases and produces monocistronic mRNA. Additionally, prokaryotic transcription and translation are coupled, while in eukaryotes they are not coupled and post-transcriptional processing occurs. Overall, both follow similar steps of initiation, elongation, and termination, but differ in their location, involved enzymes, and mRNA processing.
Molecular basis of inheritance-Protein synthesis part 1 Transcriptionein ppt...Nilima Patil
The document summarizes the process of protein synthesis, which involves two main steps - transcription and translation. Transcription occurs in the nucleus, where DNA is transcribed into mRNA by RNA polymerase. The mRNA then acts as a messenger to carry the genetic code to the cytoplasm, where translation occurs on ribosomes to synthesize proteins based on the mRNA sequence. The central dogma of molecular biology describes the flow of genetic information from DNA to RNA to protein. Some viruses use reverse transcription to produce DNA from their RNA genetic material.
RNA exists in several forms that are involved in protein synthesis and regulation. Major RNA types include messenger RNA (mRNA), which carries genetic code from DNA to ribosomes for protein production. Ribosomal RNA (rRNA) is a core component of ribosomes where protein synthesis occurs. Transfer RNA (tRNA) transports amino acids to the ribosome during protein assembly. Small nuclear RNAs (snRNAs) help process mRNA, while microRNAs (miRNAs) and small interfering RNAs (siRNAs) regulate gene expression. Certain RNA molecules function as catalysts in cells. New research indicates miRNAs and siRNAs could be targeted for therapeutic drug development.
This document provides an overview of non-coding RNA (ncRNA), including long ncRNAs and small ncRNAs. It discusses different types of small ncRNAs such as microRNAs (miRNAs), piRNAs, and small interfering RNAs (siRNAs). The document describes the biogenesis and mechanisms of action of these ncRNAs. It provides examples of functions for long ncRNAs and the role of the siRNA pathway in preventing transgenerational retrotransposition in plants under stress. In summary, the document categorizes and explains the major types and roles of coding and non-coding RNAs.
Gene expression is the process by which the information from a gene is used in the synthesis of a functional gene product. It involves two main stages - transcription of DNA to mRNA and translation of mRNA to protein. In eukaryotes, gene expression requires several processing steps between transcription and translation including 5' capping, splicing, and 3' polyadenylation of mRNA. Protein synthesis occurs via three phases - initiation, elongation, and termination on ribosomes in the cytoplasm. Gene expression is regulated at multiple levels including transcription, RNA processing, translation and post-translation.
This document provides an overview of RNA editing. It begins by defining RNA editing as any process that results in a change to an RNA transcript sequence compared to the DNA template, excluding splicing. It then discusses the two main types of editing - base modification and insertion/deletion. Key points include that editing occurs in the nucleus, mitochondria and chloroplasts; the mechanism of pan editing in kinetoplastids involving guide RNAs; and examples of A-to-I and C-to-U editing in humans. The document also summarizes a case study on the role of the SLO2 gene in plant stress responses through regulation of mitochondrial electron transport.
RNA editing is a term associated with structural changes in an RNA strand that alter its coding properties. These enzyme-catalyzed reactions include nucleotide and oligonucleotide insertions and deletions as well as base modifications. The diversity of coding strands created by these reactions contributes to the protein diversity present in cells of higher organisms. In this review, we highlight advances in our understanding of the structure, mechanism, regulation, and biological functions of the ADAR enzymes published in the last five years. The ADARs (adenosine deaminases that act on RNA) are multidomain enzymes capable of converting adenosine to inosine at specific locations in certain RNA substrates. These reactions can change codon meaning in mRNA and lead to changes in the structures of proteins, including ligand-gated and voltage-gated ion channels and G-protein coupled receptors expressed in the central nervous system.
This document summarizes key aspects of gene transcription including:
1. Transcription is important for regulating cellular function and aberrant control can cause disease.
2. In eukaryotes, transcription and translation are separated in space and time, and primary RNA transcripts undergo extensive processing.
3. Prokaryotic transcription involves RNA polymerase recognizing promoters and transcribing DNA into RNA with sigma factors providing specificity. Eukaryotic transcription involves three RNA polymerases and more complex promoters.
Translation involves mRNA carrying genetic code from the nucleus to the cytoplasm, where ribosomes decode the code into proteins. Ribosomes attach to mRNA and read its sequence three nucleotides at a time, using transfer RNA and its anticodons to specify amino acids. Peptidyl transferase catalyzes the formation of peptide bonds between amino acids into a polypeptide chain. Multiple ribosomes can attach to a single mRNA strand simultaneously to speed up protein production.
This document discusses RNA structure and types. It begins by describing the basic components and functions of RNA, including its role in transcription and as an intermediate molecule in protein synthesis. It then discusses the different forms and structures of RNA, including primary, secondary and tertiary structures. The main types of RNA - mRNA, tRNA, rRNA and others like miRNA and siRNA - are then summarized in terms of their roles and characteristics. Applications of RNA interference are also briefly outlined.
Transcriptional and post transcriptional regulation of gene expressionDr. Kirti Mehta
Gene expression is regulated at the transcriptional and post-transcriptional levels. Transcriptional regulation involves proteins binding to promoter and enhancer sequences to control RNA polymerase recruitment and initiation of transcription. Eukaryotic gene expression requires transcription factors, coactivators, and basal transcription factors to assemble the transcription initiation complex. Post-transcriptional regulation influences RNA processing, transport, translation, and degradation.
The document discusses genetic control of protein synthesis, cell function, and cell reproduction. It begins by outlining the central dogma of gene expression, including the structures of DNA and RNA and the processes of transcription and translation. It then describes the stages of the cell cycle, including interphase and the four phases of mitosis - prophase, metaphase, anaphase, and telophase. It explains the key events that occur during each phase, such as chromosome condensation, alignment at the metaphase plate, and separation of sister chromatids.
The document summarizes the role of non-coding RNAs in DNA replication initiation. It discusses how the Tetrahymena 26T RNA interacts with the origin recognition complex (ORC) to recruit it specifically to the rDNA origin for replication initiation. It also describes how the Epstein-Barr virus encodes a G-rich RNA that recruits the human ORC complex through its interaction with EBNA1. Additionally, the document outlines the essential role of vertebrate Y RNAs in mammalian DNA replication, particularly in the initiation step of the process.
The document summarizes research on RNA splicing and A-to-I RNA editing. Key findings include:
- JetPEI performed better than PEI as a transfection reagent with lower toxicity at low concentrations.
- Co-transfection with ADAR1 showed no changes in editing levels between three Azin1 constructs.
- The three Gria2 constructs showed that longer splicing duration was positively correlated with higher editing frequency.
- Producing new Gria2 constructs with single mutations in the pyrimidine rich tract could provide better insight into the coupling of splicing and editing.
1) A synapse is a junction that transmits signals between neurons. It contains a presynaptic terminal that releases neurotransmitters and a postsynaptic membrane with receptors.
2) When an action potential reaches the presynaptic terminal, calcium ions enter and cause neurotransmitter vesicles to fuse and release their contents across the synaptic cleft.
3) Neurotransmitters bind to and open ion channels on the postsynaptic membrane, producing an electrical effect that may trigger another action potential.
The document discusses the concept of the synapse between neurons. It describes how synapses allow neurons to communicate via neurotransmitters. Neurotransmitters are released from the presynaptic neuron and bind to receptors on the postsynaptic neuron, which can excite or inhibit the postsynaptic neuron. The document outlines different types of neurotransmitters and how they work, including their synthesis, transport, release, effects, and inactivation methods like reuptake. It also discusses how drugs can influence synaptic activity and neurotransmitters. Finally, it suggests synapses may be important for personality traits and behaviors.
The document summarizes the process of translation, which involves mRNA being decoded by ribosomes to produce a specific amino acid sequence. It describes the three stages of translation - initiation, elongation, and termination. Key components like mRNA, ribosomes, tRNAs, and aminoacyl-tRNA synthetases are discussed. The roles of these components in reading the genetic code contained in mRNA and synthesizing polypeptide chains are explained over multiple paragraphs.
Long non coding RNA and Their clinical perspectiveMOHIT GOSWAMI
This document discusses long non-coding RNAs (lncRNAs), which are RNA molecules longer than 200 nucleotides that do not code for proteins but play important regulatory roles. It describes the central dogma of molecular biology and how most of the human genome is transcribed into non-coding RNA. It classifies lncRNAs and explains their potential functions as signals, decoys, guides and scaffolds. The document also discusses the roles of lncRNAs in several human diseases like cancer, Alzheimer's, diabetes and more. It concludes that lncRNAs are important biomarkers and therapeutic targets due to their involvement in complex disease pathogenesis.
Almost 98 of the human genome does not encode proteins
o The non coding transcripts less than 200 bases are called small non
coding RNA and comprise of tRNA, rRNA, miRNA, snoRNA, piwi
interacting RNA (pi RNA)
o RNA molecules that are of more than 200 bases in length are known
as long non coding RNA (
o lncRNAs are more than 200 nucleotides in length and also can be
more than 2 Kb
o Such long noncoding RNAs usually have limited coding potential due
to the absence of open reading frames, 3 UTR and termination
region while their coding potential is less than 100 amino acids
RNA exists in various forms that perform important cellular functions. The major types of RNA include messenger RNA (mRNA), which carries genetic information from DNA to direct protein synthesis, transfer RNA (tRNA) that transports amino acids, and ribosomal RNA (rRNA) which combines with proteins to form ribosomes and facilitate protein synthesis. Other RNAs include small nuclear RNAs that process mRNA, microRNAs and small interfering RNAs that regulate gene expression, and heterogeneous nuclear RNA that is processed into mRNA.
- mRNA carries genetic information from DNA to the ribosome where protein synthesis occurs. It is single-stranded and complementary to one DNA strand.
- rRNA makes up 80% of cellular RNA and is a component of ribosomes. rRNA molecules synthesized in the nucleolus combine with proteins to form ribosomes, the sites of protein synthesis.
- tRNA acts as an intermediary between mRNA and amino acids during protein synthesis. It has a cloverleaf secondary structure and binds to specific amino acids to deliver them to the ribosome based on the mRNA sequence.
This document summarizes various processes involved in RNA processing in eukaryotes. It discusses 5' capping and polyadenylation of pre-mRNA, as well as splicing of introns and exons. Splicing involves two transesterification reactions catalyzed by a spliceosome complex containing U1, U2, U4, U5 and U6 small nuclear ribonucleoproteins (snRNPs). Alternative splicing and RNA editing are also described, where editing can involve base modification or insertion/deletion of nucleotides guided by small RNAs.
Prokaryotic and eukaryotic transcription differ in several key ways. Prokaryotic transcription occurs in the cytoplasm and uses a single RNA polymerase to produce polycistronic mRNA, while eukaryotic transcription takes place in the nucleus using three RNA polymerases and produces monocistronic mRNA. Additionally, prokaryotic transcription and translation are coupled, while in eukaryotes they are not coupled and post-transcriptional processing occurs. Overall, both follow similar steps of initiation, elongation, and termination, but differ in their location, involved enzymes, and mRNA processing.
Molecular basis of inheritance-Protein synthesis part 1 Transcriptionein ppt...Nilima Patil
The document summarizes the process of protein synthesis, which involves two main steps - transcription and translation. Transcription occurs in the nucleus, where DNA is transcribed into mRNA by RNA polymerase. The mRNA then acts as a messenger to carry the genetic code to the cytoplasm, where translation occurs on ribosomes to synthesize proteins based on the mRNA sequence. The central dogma of molecular biology describes the flow of genetic information from DNA to RNA to protein. Some viruses use reverse transcription to produce DNA from their RNA genetic material.
RNA exists in several forms that are involved in protein synthesis and regulation. Major RNA types include messenger RNA (mRNA), which carries genetic code from DNA to ribosomes for protein production. Ribosomal RNA (rRNA) is a core component of ribosomes where protein synthesis occurs. Transfer RNA (tRNA) transports amino acids to the ribosome during protein assembly. Small nuclear RNAs (snRNAs) help process mRNA, while microRNAs (miRNAs) and small interfering RNAs (siRNAs) regulate gene expression. Certain RNA molecules function as catalysts in cells. New research indicates miRNAs and siRNAs could be targeted for therapeutic drug development.
This document provides an overview of non-coding RNA (ncRNA), including long ncRNAs and small ncRNAs. It discusses different types of small ncRNAs such as microRNAs (miRNAs), piRNAs, and small interfering RNAs (siRNAs). The document describes the biogenesis and mechanisms of action of these ncRNAs. It provides examples of functions for long ncRNAs and the role of the siRNA pathway in preventing transgenerational retrotransposition in plants under stress. In summary, the document categorizes and explains the major types and roles of coding and non-coding RNAs.
Gene expression is the process by which the information from a gene is used in the synthesis of a functional gene product. It involves two main stages - transcription of DNA to mRNA and translation of mRNA to protein. In eukaryotes, gene expression requires several processing steps between transcription and translation including 5' capping, splicing, and 3' polyadenylation of mRNA. Protein synthesis occurs via three phases - initiation, elongation, and termination on ribosomes in the cytoplasm. Gene expression is regulated at multiple levels including transcription, RNA processing, translation and post-translation.
This document provides an overview of RNA editing. It begins by defining RNA editing as any process that results in a change to an RNA transcript sequence compared to the DNA template, excluding splicing. It then discusses the two main types of editing - base modification and insertion/deletion. Key points include that editing occurs in the nucleus, mitochondria and chloroplasts; the mechanism of pan editing in kinetoplastids involving guide RNAs; and examples of A-to-I and C-to-U editing in humans. The document also summarizes a case study on the role of the SLO2 gene in plant stress responses through regulation of mitochondrial electron transport.
RNA editing is a term associated with structural changes in an RNA strand that alter its coding properties. These enzyme-catalyzed reactions include nucleotide and oligonucleotide insertions and deletions as well as base modifications. The diversity of coding strands created by these reactions contributes to the protein diversity present in cells of higher organisms. In this review, we highlight advances in our understanding of the structure, mechanism, regulation, and biological functions of the ADAR enzymes published in the last five years. The ADARs (adenosine deaminases that act on RNA) are multidomain enzymes capable of converting adenosine to inosine at specific locations in certain RNA substrates. These reactions can change codon meaning in mRNA and lead to changes in the structures of proteins, including ligand-gated and voltage-gated ion channels and G-protein coupled receptors expressed in the central nervous system.
This document summarizes key aspects of gene transcription including:
1. Transcription is important for regulating cellular function and aberrant control can cause disease.
2. In eukaryotes, transcription and translation are separated in space and time, and primary RNA transcripts undergo extensive processing.
3. Prokaryotic transcription involves RNA polymerase recognizing promoters and transcribing DNA into RNA with sigma factors providing specificity. Eukaryotic transcription involves three RNA polymerases and more complex promoters.
Translation involves mRNA carrying genetic code from the nucleus to the cytoplasm, where ribosomes decode the code into proteins. Ribosomes attach to mRNA and read its sequence three nucleotides at a time, using transfer RNA and its anticodons to specify amino acids. Peptidyl transferase catalyzes the formation of peptide bonds between amino acids into a polypeptide chain. Multiple ribosomes can attach to a single mRNA strand simultaneously to speed up protein production.
This document discusses RNA structure and types. It begins by describing the basic components and functions of RNA, including its role in transcription and as an intermediate molecule in protein synthesis. It then discusses the different forms and structures of RNA, including primary, secondary and tertiary structures. The main types of RNA - mRNA, tRNA, rRNA and others like miRNA and siRNA - are then summarized in terms of their roles and characteristics. Applications of RNA interference are also briefly outlined.
Transcriptional and post transcriptional regulation of gene expressionDr. Kirti Mehta
Gene expression is regulated at the transcriptional and post-transcriptional levels. Transcriptional regulation involves proteins binding to promoter and enhancer sequences to control RNA polymerase recruitment and initiation of transcription. Eukaryotic gene expression requires transcription factors, coactivators, and basal transcription factors to assemble the transcription initiation complex. Post-transcriptional regulation influences RNA processing, transport, translation, and degradation.
The document discusses genetic control of protein synthesis, cell function, and cell reproduction. It begins by outlining the central dogma of gene expression, including the structures of DNA and RNA and the processes of transcription and translation. It then describes the stages of the cell cycle, including interphase and the four phases of mitosis - prophase, metaphase, anaphase, and telophase. It explains the key events that occur during each phase, such as chromosome condensation, alignment at the metaphase plate, and separation of sister chromatids.
The document summarizes the role of non-coding RNAs in DNA replication initiation. It discusses how the Tetrahymena 26T RNA interacts with the origin recognition complex (ORC) to recruit it specifically to the rDNA origin for replication initiation. It also describes how the Epstein-Barr virus encodes a G-rich RNA that recruits the human ORC complex through its interaction with EBNA1. Additionally, the document outlines the essential role of vertebrate Y RNAs in mammalian DNA replication, particularly in the initiation step of the process.
The document summarizes research on RNA splicing and A-to-I RNA editing. Key findings include:
- JetPEI performed better than PEI as a transfection reagent with lower toxicity at low concentrations.
- Co-transfection with ADAR1 showed no changes in editing levels between three Azin1 constructs.
- The three Gria2 constructs showed that longer splicing duration was positively correlated with higher editing frequency.
- Producing new Gria2 constructs with single mutations in the pyrimidine rich tract could provide better insight into the coupling of splicing and editing.
1) A synapse is a junction that transmits signals between neurons. It contains a presynaptic terminal that releases neurotransmitters and a postsynaptic membrane with receptors.
2) When an action potential reaches the presynaptic terminal, calcium ions enter and cause neurotransmitter vesicles to fuse and release their contents across the synaptic cleft.
3) Neurotransmitters bind to and open ion channels on the postsynaptic membrane, producing an electrical effect that may trigger another action potential.
The document discusses the concept of the synapse between neurons. It describes how synapses allow neurons to communicate via neurotransmitters. Neurotransmitters are released from the presynaptic neuron and bind to receptors on the postsynaptic neuron, which can excite or inhibit the postsynaptic neuron. The document outlines different types of neurotransmitters and how they work, including their synthesis, transport, release, effects, and inactivation methods like reuptake. It also discusses how drugs can influence synaptic activity and neurotransmitters. Finally, it suggests synapses may be important for personality traits and behaviors.
The Synapse And The Presynaptic And Postsynaptic Terminalsneurosciust
Neurons communicate with each other via connections between axons and dendrites called synapses. At a synapse, the presynaptic terminal of one neuron releases neurotransmitters into the synaptic gap when an action potential arrives. The neurotransmitters then bind to receptors on the postsynaptic terminal of the next neuron, making that neuron more or less likely to fire an action potential and pass the signal on. For a signal to be transmitted across a synapse, neurotransmitters must be produced, transported to the presynaptic terminal, released into the gap upon arrival of an action potential, and bind to receptors on the postsynaptic terminal.
Graded potentials are local changes in membrane potential that vary in strength depending on the stimulus. They spread through passive diffusion but decay over short distances. Action potentials occur when the membrane reaches threshold potential, causing voltage-gated sodium and potassium channels to open and reverse the membrane potential before restoring it. They travel along axons through contiguous conduction. At synapses, neurotransmitters released from presynaptic neurons can excite or inhibit postsynaptic neurons through temporal and spatial summation of EPSPs and IPSPs. Presynaptic inputs determine postsynaptic responses through facilitation or inhibition of neurotransmitter release.
A synapse is the junction between neurons that allows electrical or chemical signals to pass from one cell to another. At a chemical synapse, an action potential in the presynaptic neuron causes neurotransmitters to be released into the synaptic cleft. These neurotransmitters then bind to receptors on the postsynaptic cell, causing ion channels to open and potentially triggering an action potential in that cell. Precise transmission of signals across synapses is crucial for normal nervous system function.
Neurotransmitters dr. jawad class of 2015Muhammad Saim
This document summarizes key information about neurotransmitters. It outlines the criteria for classifying a molecule as a neurotransmitter, identifies major neurotransmitter types including acetylcholine, catecholamines, serotonin, histamine, glutamate, aspartate, GABA, and glycine. It describes the biochemical pathways for neurotransmitter synthesis and degradation and identifies some clinical disorders that can arise from disrupted neurotransmitter metabolism.
Synaptic transmission involves the transfer of information from the axon terminal of one neuron to the next neuron across the synaptic cleft via the release of neurotransmitters. Neurotransmitters are contained in vesicles and are released into the synaptic cleft upon the arrival of an action potential, where they bind to receptors on the postsynaptic neuron, causing ion channels to open and generate postsynaptic potentials. The integration of excitatory and inhibitory postsynaptic potentials determines whether the postsynaptic neuron reaches its firing threshold. Chemical synaptic transmission allows for flexibility, plasticity, and amplification of neuronal signals compared to electrical transmission.
This document provides an overview of synapses, including their definition, structure, function, types of transmission (electrical vs. chemical), neurotransmitters, and various properties like synaptic delay, fatigue, summation, and more. It discusses excitatory and inhibitory neurotransmitters and how convergence and divergence allow signals to be dispersed or combined. Clinical implications are that problems with synaptic transmission can cause diseases like Parkinson's and Alzheimer's.
This document discusses PIWI-interacting RNAs (piRNAs), a class of small non-coding RNAs that interact with PIWI proteins. It describes how piRNAs were discovered in Drosophila and their role in silencing transposons in the germline. The document outlines piRNA biogenesis, including their location in clusters in genomes and the "ping-pong" mechanism of biogenesis. It also discusses compartmentalization of the piRNA pathway and functions of piRNAs in maintaining genome integrity, transposon silencing, and fertility.
1) The document discusses common intracellular signaling pathways that are involved in both growth/differentiation processes early in development and synaptic plasticity in mature neurons.
2) Two examples are described in detail: the Ras-PI3K pathway and signaling elicited by neural cell adhesion molecules (NCAMs) interacting with growth factor receptors.
3) For the Ras-PI3K pathway, calcium entry via NMDA receptors can activate Ras, which then activates PI3K to produce PIP3 and drive LTP. Alternatively, NMDA receptors can activate Rap proteins to induce PTEN, reduce PIP3, and drive LTD.
1) The active zone is composed of an evolutionarily conserved protein complex containing RIM, Munc13, RIM-BP, α-liprin, and ELKS proteins as core constituents. This complex docks and primes synaptic vesicles for exocytosis.
2) In addition to transmitting information, synapses transform information encoded in bursts of action potentials through short-term and long-term plasticity mediated by the active zone protein complex.
3) The five core proteins work together to recruit voltage-gated calcium channels to the active zone, position the active zone opposite postsynaptic specializations, and mediate both short-term and long-term presynaptic plasticity.
Presentation describes types of sn-RNA its classes,translation of sn-RNA,post translational mechanisms and its role in rna spliceosomal mediated splicing of RNA, and 3' end maturation of histone genes.It also gives information about different diseases related to sn-RNA
Molecular mechanism of light perception, signal transduction and gene regulationZuby Gohar Ansari
1. The document discusses the molecular mechanisms of light perception, signal transduction, and gene regulation in plants. It describes the three main photoreceptors - phytochromes, cryptochromes, and phototropins.
2. Phytochromes exist in two forms, Pr and Pfr, and are involved in detecting red and far-red light. Upon light absorption, they are localized to the nucleus and phosphorylate downstream targets to regulate gene expression.
3. Cryptochromes mediate responses to blue light, such as inhibition of hypocotyl growth. They share structural similarities to photolyases but do not repair DNA damage.
This document reports that brain fatty acid binding protein (Fabp7) mRNA levels in the brain undergo diurnal changes in adult rodents. Specifically:
1) Fabp7 mRNA levels were higher during the light period and lower during the dark period in brain regions involved in sleep and activity like the tuberomammillary nucleus, pons, and locus coeruleus.
2) This diurnal pattern of Fabp7 mRNA expression occurred throughout the entire brain and was also seen in granule cell precursors of the adult hippocampus.
3) In contrast, the fatty acid binding protein Fabp5 did not show diurnal changes in these brain regions, indicating Fabp7 expression has a unique synchronized
This protein has tremendous potential applications in molecular biology. Lukyanov and his group found that the green fluorescent protein (GFP) chromophore can act as an electron donor when excited, donating an electron to an electron acceptor to form a short-lived intermediate. If no electron acceptor is available, the intermediate is permanently bleached, but if it reacts with an acceptor, the GFP reddens. The most successful applications of GFP have been as a genetic fusion partner, where the GFP gene is fused to a gene of interest to monitor the localization and fate of the resulting fusion protein in cells or organisms. GFP was discovered from marine organisms and has revolutionized cellular biology, with potential applications in gene expression, protein
This document discusses the role of 14-3-3 proteins in mediating the actions of insulin. It begins by explaining that insulin has wider physiological effects beyond regulating blood glucose levels, and that 14-3-3 proteins help integrate insulin signaling pathways. Specifically, 14-3-3 proteins bind to phosphorylated proteins regulated by the PI3K-PKB-mTORC1 and ERK-p90RSK pathways. They interact with AS160 and TBC1D1 to regulate glucose uptake in response to insulin and energy stress. Studying the dynamic 14-3-3 phosphoproteome is providing new insights into how insulin triggers shifts in metabolism.
This document discusses a study examining the interaction between dopamine and histamine in the basal ganglia. It provides background information on synaptic transmission, the histaminergic system, dopamine signaling in the striatum, and Parkinson's disease. The study aims to investigate how activation of dopamine D1 receptors regulates phosphorylation of glutamate AMPA receptors and DARPP-32 in striatal slices, and how histamine H3 receptor activation may oppose these effects of dopamine signaling. The results suggest dopamine increases phosphorylation of AMPA receptors and DARPP-32, while histamine H3 receptor activation reduces dopamine-induced phosphorylation, indicating opposing regulation of cAMP/PKA signaling by dopamine and histamine in striatal neurons.
Hello everyone, I am Dr. Ujwalkumar Trivedi, Head of Biotechnology Department at Marwadi University Rajkot. I teach Molecular Biology to the students of M.Sc. Microbiology and Biotechnology.
The current presentation describes various co-transcriptional and post-transcriptional RNA modifications in eukaryotic cells. The following processes are described in detail:
1. 5' mRNA Capping
2. Splicing
3. Alternative Splicing
4. 3' Polyadenylation
5. RNA Editing
Enjoy Reading.
RNA splicing is a process in which introns are removed from pre-mRNA transcripts and exons are joined together to produce mature mRNA. There are three main types of splicing pathways: spliceosomal splicing, self-splicing, and tRNA splicing. Spliceosomal splicing involves the spliceosome complex and is the most common in eukaryotes. Self-splicing occurs without proteins through ribozyme activity. tRNA splicing uses ribonucleases and ligases. Alternative splicing allows different mRNA isoforms to be produced from the same pre-mRNA. Splicing errors can cause genetic diseases by disrupting protein sequences.
OLM interneurons differentially modulate CA3 and entorhinal inputs to hippoca...Carlos Bella
This study found that OLM interneurons in the hippocampus differentially modulate inputs to CA1 neurons from the CA3 region versus the entorhinal cortex. The study identified CHRNA2 as a precise molecular marker for OLM cells. Using transgenic mice and optogenetic tools, the study showed that OLM cells facilitate transmission of intrahippocampal information from CA3 while reducing influence from extrahippocampal entorhinal cortex inputs. The study also found that OLM cells receive direct cholinergic inputs from the medial septum and diagonal band of Broca and are important for gating information flow and synaptic plasticity in CA1.
Multifunctional nucleolus in Plant cell growth and development.Bhawna Mishra
This document provides an overview of the nucleolus in plant cells. It discusses that the nucleolus is made up of fibrillar centers, dense fibrillar compartments, and granular centers, and its main function is ribosome biosynthesis. It also notes that the nucleolus is involved in other processes like RNA regulation, cell cycle progression, genome maintenance, and stress response. Specific proteins and pathways in each of these functions are outlined. Recent research topics discussed include the nucleolus's role in DNA repair, links to the proteasome, and effects of nucleolar protein deficiencies on plant growth and development.
1. The document discusses lateral root development in Arabidopsis thaliana, including the initiation and stages of lateral root primordia formation. Key processes like cell division and emergence are described.
2. Lateral root development is regulated by auxin and other signals in a transcriptional cascade. Auxin binds to repressor proteins and activates transcription factors that regulate genes involved in cell wall remodeling and lateral root primordia development.
3. The document also covers root gravitropism, describing the three phases of gravity perception in columella cells, signal transduction through auxin transport, and the gravitropic response through differential cell elongation. Many genes involved in these processes remain unidentified.
Flourescent Proteins and its Applications in Cell biologyMoheer07
Fluorescent proteins are self-sufficient proteins that form a visible fluorescent molecule from amino acids within their own polypeptide sequence. GFP was first isolated from jellyfish in the 1960s, and its gene was cloned in 1992, allowing expression in other organisms. There are several types of fluorescent proteins that differ in color, including GFP, CFP, YFP, and RFP. Fluorescent proteins are widely used as markers to track proteins, observe protein interactions, and study biological processes in living cells and organisms.
1. The study found that NMDA receptor activation triggers an association between the tumor suppressor protein PTEN and the synaptic scaffolding protein PSD-95.
2. This association requires a PDZ-binding motif on PTEN and leads to PTEN being recruited to and anchored at dendritic spines.
3. Enhancing PTEN's lipid phosphatase activity was found to specifically drive depression of AMPA receptor-mediated synaptic responses, and this activity was required for NMDA receptor-dependent long-term depression (LTD) but not other forms of plasticity.
This document discusses phospholipase C (PLC) and its role in neutrophil degranulation and T cell cytotoxicity. PLC hydrolyzes phosphatidylinositol 4,5-bisphosphate (PIP2) into two second messengers, diacylglycerol and inositol 1,4,5-trisphosphate. PLC signaling is required for lytic granule polarization and effective T cell killing through T cell antigen receptor activation. Neutrophil degranulation involves increases in calcium and PLC production of phosphatidylinositol, which is essential for granule exocytosis. Different intracellular signaling pathways regulate the release of primary, secondary, and tertiary granules from neutroph
RNA SYNTHESIS AND SPLICING "biochemistrySarahAshfaq4
The document summarizes RNA synthesis and splicing. It discusses that in eukaryotes, RNA is processed after synthesis from DNA in the nucleus. There are three main types of RNA splicing - self-splicing via ribozymes, spliceosomal splicing involving protein complexes, and polyadenylation of mRNA. Introns are non-coding regions that are spliced out, while exons are coding regions that are joined to form mature mRNA. Small nuclear RNAs and proteins form spliceosomes that catalyze splicing of spliceosomal introns in eukaryotic pre-mRNA.
This chapter discusses the amygdala in Alzheimer's disease (AD). It notes that the amygdala is severely affected by AD pathology and is involved in emotional processing. Damage to the amygdala in AD leads to neuropsychiatric symptoms like anxiety and personality changes in patients. Studies also show impaired emotional memory in AD patients that correlates with amygdala atrophy. Autopsies reveal neurofibrillary tangles, amyloid plaques and neuronal loss in the amygdala of AD patients. Imaging studies further demonstrate amygdala volume reductions in AD patients, even in early stages, associated with cognitive impairment.
Morphological alterations to neurons of the amygdalashiraknafo
This study examined the effects of amyloid-beta (Aβ) accumulation in the amygdala of an Alzheimer's disease mouse model. The mice showed impaired fear conditioning compared to controls. While there was no neuronal loss in the lateral nucleus of the amygdala (LA), the dendritic trees and spines of LA projection neurons were morphologically altered. Specifically, plaque-free neurons in the transgenic mice had decreased large dendritic spines compared to controls. This suggests that Aβ deposition leads to structural changes in the amygdala that may underlie impaired emotional memory seen in Alzheimer's disease.
Spines, plasticity, and cognition in alzheimer model mice.shiraknafo
This review article discusses research on transgenic Alzheimer's disease (AD) mouse models and how they are used to investigate dendritic spine structure, synaptic function, and cognition. Studies show that soluble amyloid-beta initiates synaptic dysfunction and loss, as well as tau pathology, contributing to both synaptic and neuronal loss. These changes in synapse structure and function, as well as outright synapse and neuron loss, underlie the neural system dysfunction that causes cognitive deficits in AD. Understanding how dementia develops in AD is crucial for developing effective therapies.
WIP is a negative regulator of neuronal maturation and synaptic activity. Mice lacking WIP (WIP-/-) have enlarged neuronal somas and overgrown neuritic and dendritic branches, especially during early development. WIP-/- neurons also have increased amplitude and frequency of miniature excitatory postsynaptic currents, indicating more mature synapses than in wild-type neurons. This reveals WIP as a previously unknown regulator of neuronal maturation and synaptic activity.
This study analyzed dendritic spine morphology in the CA1 region of the hippocampus in a mouse model of Alzheimer's disease (AD). Three key findings were observed:
1) Dendritic spine necks in the stratum oriens layer were significantly shorter in AD mice compared to controls.
2) The frequency of dendritic spines with small head volumes increased in the stratum radiatum layer of AD mice.
3) These layer-specific changes to spine morphology in an AD mouse model may underlie the synaptic dysfunction and cognitive impairments seen in the disease. The changes reflect the effects of amyloid-beta overexpression on excitatory synapses in the hippocampus.
1) A peptide called FGL enhances learning and memory in rodents by stimulating the delivery of glutamate receptors to synapses, strengthening synaptic transmission. This effect is mediated through the activation of protein kinase C.
2) FGL treatment heightens the induction of long-term potentiation in response to synaptic activity, improving the encoding of information.
3) FGL is poised to begin clinical trials this year for Alzheimer's disease, as prior studies show it improves memory and reduces neuropathology in rodent models of AD.
1) The study assessed changes in hippocampal dendritic spines of APP/PS1 transgenic mice, a model of Alzheimer's disease.
2) It found a substantial decrease in the frequency of large dendritic spines in plaque-free regions of the dentate gyrus in these mice compared to controls.
3) Dendrites passing through amyloid plaques also showed alterations in spine density and morphology, with lower spine density within plaques and higher density on dendrites contacting plaques.
This document summarizes research investigating the cellular and molecular mechanisms underlying cognitive enhancement induced by a peptide called FGL. The key findings are:
1. FGL activates fibroblast growth factor receptor (FGFR) signaling pathways in vivo and in vitro.
2. FGL enhances long-term potentiation (LTP) in hippocampal slices by facilitating delivery of AMPA receptors to synapses through activation of NMDA receptors.
3. Both the LTP enhancement and cognitive improvement produced by FGL are mediated by initial protein kinase C (PKC) activation followed by sustained calcium/calmodulin-dependent protein kinase II (CaMKII) activation.
4. These results link facilitation
1. The study used high-resolution fluorescence recovery after photobleaching (FRAP) to examine the dynamics and organization of AMPA receptors (AMPARs) within the postsynaptic density (PSD) of single dendritic spines in cultured hippocampal neurons.
2. They found that under basal conditions, AMPARs showed limited lateral diffusion within the PSD, but clustered together in a matrix that continuously reshaped in an actin-dependent manner.
3. Application of glutamate increased the intrasynaptic mobility of AMPARs, suggesting activated synapses promote exchange of receptors among subdomains. This supports the idea that the PSD regulates subsynaptic receptor distribution.
This article reviews studies on transgenic Alzheimer's disease (AD) mouse models that investigate dendritic spine structure, synaptic function, and cognition. These studies show that soluble amyloid-beta initiates synaptic dysfunction and loss, as well as pathological changes in tau, which contribute to both synaptic and neuronal loss. In vivo imaging reveals plaque-associated spine loss and structural plasticity deficits in AD mouse models. Synaptic plasticity is also severely impaired in AD mouse models, with deficits in basal synaptic transmission and long-term potentiation emerging with age. Together, these changes in synapse structure and function are thought to underlie the cognitive deficits observed in AD.