RNA Interference and RNA Silencing• RNA Interference (RNAi)- is a highly evolutionally conserved process of post- transcriptional gene silencing (PTGS) by which double stranded RNA (dsRNA), when introduced into a cell, causes sequence-specific degradation of homogolous mRNA sequences.
• 1998- it was introduced by Andrew Fire and Craig Mello in the nematode worm Caenorhabditis elegans and later found in a wide variety of organisms, including mamals.• RNAi is believed to be universal as it has been observed in all eukaryotes, from yeast to mamals.
The most interesting aspects of RNAi are the following:• dsRNA, rather than single-stranded antisense RNA, is the interfering agent.• It is highly specific• It is remarkably potent• the interfering activity can cause interference in cells and tissues far removed from the site of introduction.
Application of RNAi1. Determining Gene Function2. Pathway Analysis3. Identify and Validate drug Targets4. Study Gene Redundancy5. Functional Screening
Timelin Who What Organism e Guo S, and First noticed that sense RNA was1995 Kemphues KJ. as effective as antisense C. elegans RNA for Suppressing Gene expression in worm First described RNAi Phenomenon1998 Fire et al. in C. elegans by injecting dsRNA into C. elegans which led to an C. elegans efficient sequence- specific silencing and coined the term “RNA Interference”. Reported processing of long dsRNA2000 Zamore et al. by Rnase II (Dicer) into shorter Drosophila fragments of 21-23-nt intervals in Drosophila extracts
Cloned Dicer, the Rnase III enzyme that is2001 Bernstein et al. evolutionarily conserved and contains C. elegans helicase and PAZ domains, as well as two dsRNA- Binding domains.2001 Tuschl T and Mammals colleagues First described RNAi in Mammalian cells.2003 Paddison et al. Short hairpin RNAs (shRNAs) induce Mammals Sui et al. sequence- specific silencing in mamalian cells. Paul et al.2003 First reported that siRNAs can be used Mammals Song et al. therapeutically in whole animals.2004 Kawasaki and First observed that siRNA silences gene at Human Taira transcriptional level possibly through Morris et al. directing de novo DNA methylation. Andrew Fire Won Noble Prize in Physiology or Medicine Human2006 and for discovering RNAi mechanism. Craig Mello2006 Li et al First reported that small dsRNA induces Human gene expresion activation, a phenomenon termed as RNAa.
DNA Microarray Technology?• DNA Microarray Technology- have been developed in the 1990s as a method of rapidly analyzing the expression of thousands of genes all at the same time by allowing the RNA products of genes to be monitored at once.
How do DNA microarrays work?• DNA microarray work by providing fixed single strands of Dna (gene sequences) to which labeled cDNA fragments can bind. Thousands of different genes are immobilized onto ma small, inert, solid support (called a chip), which is usually a glass microscope slide, but can also be a silicon chip or a nylon membrane.
Application of DNA microarrays work?• Correlating Gene Expression with metabolic Changes• Characterizing nCell Types• Cancer Research• Toxicology
FBI CODIS (Combined DNA Index System) for Human Identification• In 1997 the US FBI (Federal Bureau of Investigation) Selected thirteen STR (Short Tandem Repeat) loci in human chromosomes foe use as standards in human identification and genome signature comparison.
Why use STRs (Short Tandem Repeats)?• Short Tandem Repeats (STRs) offer several advantages over RFLPs as tools for human identification.• STRs exhibit high heterozygosity• STRs exhibit a regular repeat pattern• STRs are easily amplified
IV. Nanotechnology• Nanotechnology- refers to the design, characterization, production and application of structures, devices and systems by controlling shape and size at nanometer scale.• Nano- is derived from the greek word “dwarf”.
Bioinformatics: Shaping the Future of Biotechnology• Blast- is an algorithm that stands for Basic Local Alignment Search Tool and was developed by Altschul, Gish, Miller, Myers, and Lipman in 1990.• It is used to search for related sequences available in the database and for comparing two or more sequences for similarities.
Application in Biotechnology Research• Agriculture• Aquaculture• Human Health• Environment• Wildlife Conservation• Industry• Forensics