1. Levels of gene regulation
The observation that differences in the RNA and protein content of different tissues are not paralleled by significant differences in their DNA content indicates that the process whereby DNA produces mRNA must be the level at which gene expression is regulated in eukaryotes. In bacteria this process involves only a single stage, that of transcription, in which RNA copy of the DNA is produced by the enzyme RNA polymerase. Even while this process is still occurring, ribosomes attach to the nascent RNA chain and begin to translate it into protein. Hence cases
of gene regulation in bacteria, such as the switching on of the synthesis of the enzyme β-galactosidase in response to the presence of lactose (its substrate), are mediated by increased transcription of the appropriate gene. Clearly, a similar regulation of gene transcription in different tissues, or in response to substances such as steroid hormones which induce the synthesis of new proteins, represents an attractive method of gene regulation in eukaryotes.
In contrast to the situation in bacteria, however, a number of stages intervene between the initial synthesis of the primary RNA transcript and the eventual production of mRNA (Fig. 1).
The initial transcript is modified at its 5′ end by the addition of a cap structure containing a modified guanosine residue and is subsequently cleaved near its 3′ end, followed by the addition of up to 200 adenosine residues in a process known as polyadenylation. Subsequently, intervening sequences or introns, which interrupt the protein-coding sequence in both the DNA and the primary transcript of many genes. Although this produces a functional mRNA, the spliced molecule must then be transported from the nucleus, where these processes occur, to the cytoplasm where it can be translated into protein.
1. Levels of gene regulation
The observation that differences in the RNA and protein content of different tissues are not paralleled by significant differences in their DNA content indicates that the process whereby DNA produces mRNA must be the level at which gene expression is regulated in eukaryotes. In bacteria this process involves only a single stage, that of transcription, in which RNA copy of the DNA is produced by the enzyme RNA polymerase. Even while this process is still occurring, ribosomes attach to the nascent RNA chain and begin to translate it into protein. Hence cases
of gene regulation in bacteria, such as the switching on of the synthesis of the enzyme β-galactosidase in response to the presence of lactose (its substrate), are mediated by increased transcription of the appropriate gene. Clearly, a similar regulation of gene transcription in different tissues, or in response to substances such as steroid hormones which induce the synthesis of new proteins, represents an attractive method of gene regulation in eukaryotes.
In contrast to the situation in bacteria, however, a number of stages intervene between the initial synthesis of the primary RNA transcript and the eventual production of mRNA (Fig. 1).
The initial transcript is modified at its 5′ end by the addition of a cap structure containing a modified guanosine residue and is subsequently cleaved near its 3′ end, followed by the addition of up to 200 adenosine residues in a process known as polyadenylation. Subsequently, intervening sequences or introns, which interrupt the protein-coding sequence in both the DNA and the primary transcript of many genes. Although this produces a functional mRNA, the spliced molecule must then be transported from the nucleus, where these processes occur, to the cytoplasm where it can be translated into protein.
REGULATION OF
GENE EXPRESSION
IN PROKARYOTES & EUKARYOTES .
This presentation is enriched with lots of information of gene expression with many pictures so that anyone can understand gene expression easily.
Gene expression is the process by which the information encoded in a gene is used to direct the assembly of a protein molecule.
Gene expression is explored through a study of protein structure and function, transcription and translation, differentiation and stem cells.
It is the process by which information from a gene is used in the synthesis of a functional gene product.
These products are often proteins, but in non-protein coding genes such as ribosomal RNA (rRNA), transfer RNA (tRNA) or small nuclear RNA (snRNA) genes, the product is a functional RNA.
The process of gene expression is used by all known life - eukaryotes (including multicellular organisms), prokaryotes (bacteria and archaea)
Regulation of gene expression:
Regulation of gene expression includes a wide range of mechanisms that are used by cells to increase or decrease the production of specific gene products (protein or RNA).
Gene regulation is essential for viruses, prokaryotes and eukaryotes as it increases the versatility and adaptability of an organism by allowing the cell to express protein when needed.
CLASSIFICATION OF GENE WITH RESPECT TO THEIR EXPRESSION:
Constitutive ( house keeping) genes:
Are expressed at a fixed rate, irrespective to the cell condition.
Their structure is simpler.
Controllable genes:
Are expressed only as needed. Their amount may increase or decrease with respect to their basal level in different condition.
Their structure is relatively complicated with some response elements.
TYPES OF REGULATION OF GENE:
positive & negative regulation.
Steps involving gene regulation of prokaryotes & eukaryotes.
Operon-structure,classification of mechanisms- lac operon,tryptophan operon ,
and many things related to gene expression.
This is a video slide so anyone can understand this topic easily by seeing pictures included in this slide.
Regulation of gene expression in eukaryotesAnna Purna
Presence of nucleus and complexity of eukaryotic organism demands a well controlled gene regulation in eukaryotic cell. Tissue specific gene expression is essential as they are multicellular organisms in which different cells perform different functions. This PPT deals with various control points for the gene regulation and expression within a cell.
Gene rehulation in prokaryotes and eukaryotesSuresh Antre
Gene regulation drives the processes of cellular differentiation and morphogenesis, leading to the creation of different cell types in multicellular organisms where the different types of cells may possess different gene expression profile.
Replication,transcription,translation complete the central dogma of life.How mRNA,tRNA,rRNA act on ribosomes for protein synthesis.Difference between eukaryotes and prokaryotes
REGULATION OF
GENE EXPRESSION
IN PROKARYOTES & EUKARYOTES .
This presentation is enriched with lots of information of gene expression with many pictures so that anyone can understand gene expression easily.
Gene expression is the process by which the information encoded in a gene is used to direct the assembly of a protein molecule.
Gene expression is explored through a study of protein structure and function, transcription and translation, differentiation and stem cells.
It is the process by which information from a gene is used in the synthesis of a functional gene product.
These products are often proteins, but in non-protein coding genes such as ribosomal RNA (rRNA), transfer RNA (tRNA) or small nuclear RNA (snRNA) genes, the product is a functional RNA.
The process of gene expression is used by all known life - eukaryotes (including multicellular organisms), prokaryotes (bacteria and archaea)
Regulation of gene expression:
Regulation of gene expression includes a wide range of mechanisms that are used by cells to increase or decrease the production of specific gene products (protein or RNA).
Gene regulation is essential for viruses, prokaryotes and eukaryotes as it increases the versatility and adaptability of an organism by allowing the cell to express protein when needed.
CLASSIFICATION OF GENE WITH RESPECT TO THEIR EXPRESSION:
Constitutive ( house keeping) genes:
Are expressed at a fixed rate, irrespective to the cell condition.
Their structure is simpler.
Controllable genes:
Are expressed only as needed. Their amount may increase or decrease with respect to their basal level in different condition.
Their structure is relatively complicated with some response elements.
TYPES OF REGULATION OF GENE:
positive & negative regulation.
Steps involving gene regulation of prokaryotes & eukaryotes.
Operon-structure,classification of mechanisms- lac operon,tryptophan operon ,
and many things related to gene expression.
This is a video slide so anyone can understand this topic easily by seeing pictures included in this slide.
Regulation of gene expression in eukaryotesAnna Purna
Presence of nucleus and complexity of eukaryotic organism demands a well controlled gene regulation in eukaryotic cell. Tissue specific gene expression is essential as they are multicellular organisms in which different cells perform different functions. This PPT deals with various control points for the gene regulation and expression within a cell.
Gene rehulation in prokaryotes and eukaryotesSuresh Antre
Gene regulation drives the processes of cellular differentiation and morphogenesis, leading to the creation of different cell types in multicellular organisms where the different types of cells may possess different gene expression profile.
Replication,transcription,translation complete the central dogma of life.How mRNA,tRNA,rRNA act on ribosomes for protein synthesis.Difference between eukaryotes and prokaryotes
Learn the latest eqigenetic techniques including: discriminating epigenetically inactive chromatin from active chromatin, discriminating between aberrant and Monoallelic DNA methylation, predicting gene expression levels via chromatin structure assay and analyzing how DNA methylation affects promoter activity.
The Functional and Pathway Analysis talk given in March 2010 at the CRUK CRI. Cambridge UK.
It was designed to introduce wet-lab researchers to using web-based tools for doing functional analysis of gene lists, such as from microarray experiments.
The following topics are discussed
. Prokaryotic gene expression and regulation
Prokaryotic “gene structure”
The basic structure of Operon
Lactose Operon” regulation
Tryptophan Operon” regulation
2. Eukaryotic gene expression and regulation
Eukaryotic gene structure
Regulons
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
Explore natural remedies for syphilis treatment in Singapore. Discover alternative therapies, herbal remedies, and lifestyle changes that may complement conventional treatments. Learn about holistic approaches to managing syphilis symptoms and supporting overall health.
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
Recomendações da OMS sobre cuidados maternos e neonatais para uma experiência pós-natal positiva.
Em consonância com os ODS – Objetivos do Desenvolvimento Sustentável e a Estratégia Global para a Saúde das Mulheres, Crianças e Adolescentes, e aplicando uma abordagem baseada nos direitos humanos, os esforços de cuidados pós-natais devem expandir-se para além da cobertura e da simples sobrevivência, de modo a incluir cuidados de qualidade.
Estas diretrizes visam melhorar a qualidade dos cuidados pós-natais essenciais e de rotina prestados às mulheres e aos recém-nascidos, com o objetivo final de melhorar a saúde e o bem-estar materno e neonatal.
Uma “experiência pós-natal positiva” é um resultado importante para todas as mulheres que dão à luz e para os seus recém-nascidos, estabelecendo as bases para a melhoria da saúde e do bem-estar a curto e longo prazo. Uma experiência pós-natal positiva é definida como aquela em que as mulheres, pessoas que gestam, os recém-nascidos, os casais, os pais, os cuidadores e as famílias recebem informação consistente, garantia e apoio de profissionais de saúde motivados; e onde um sistema de saúde flexível e com recursos reconheça as necessidades das mulheres e dos bebês e respeite o seu contexto cultural.
Estas diretrizes consolidadas apresentam algumas recomendações novas e já bem fundamentadas sobre cuidados pós-natais de rotina para mulheres e neonatos que recebem cuidados no pós-parto em unidades de saúde ou na comunidade, independentemente dos recursos disponíveis.
É fornecido um conjunto abrangente de recomendações para cuidados durante o período puerperal, com ênfase nos cuidados essenciais que todas as mulheres e recém-nascidos devem receber, e com a devida atenção à qualidade dos cuidados; isto é, a entrega e a experiência do cuidado recebido. Estas diretrizes atualizam e ampliam as recomendações da OMS de 2014 sobre cuidados pós-natais da mãe e do recém-nascido e complementam as atuais diretrizes da OMS sobre a gestão de complicações pós-natais.
O estabelecimento da amamentação e o manejo das principais intercorrências é contemplada.
Recomendamos muito.
Vamos discutir essas recomendações no nosso curso de pós-graduação em Aleitamento no Instituto Ciclos.
Esta publicação só está disponível em inglês até o momento.
Prof. Marcus Renato de Carvalho
www.agostodourado.com
Acute scrotum is a general term referring to an emergency condition affecting the contents or the wall of the scrotum.
There are a number of conditions that present acutely, predominantly with pain and/or swelling
A careful and detailed history and examination, and in some cases, investigations allow differentiation between these diagnoses. A prompt diagnosis is essential as the patient may require urgent surgical intervention
Testicular torsion refers to twisting of the spermatic cord, causing ischaemia of the testicle.
Testicular torsion results from inadequate fixation of the testis to the tunica vaginalis producing ischemia from reduced arterial inflow and venous outflow obstruction.
The prevalence of testicular torsion in adult patients hospitalized with acute scrotal pain is approximately 25 to 50 percent
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
1. دانشگاه علوم پزشكي وخدمات بهداش
درماني تهران
Dr. Parvin Pasalar
Tehran University of Medical Sciences
2. Objectives
To know and explain:
Regulation of Bacterial Gene Expression
Constitutive ( house keeping) vs. Controllable genes
OPERON structure and its role in gene regulation
Regulation of Eukaryotic Gene Expression at different levels:
DNA methylation
Histon modifications(Chromatin Remodeling)
Increasing the number of gene copies (gene amplification)
Changing the rate of initiation of transcription
Alternate splicing
mRNA stability
Changing the rate of initiation of translation
Using of Untranslating Region (UTR)
protein stability
Hormonal regulation
Cross talk between different regulatory pathways
3. Classification of gene with respect to
their Expression
Constitutive ( house keeping) genes:
1- Are expressed at a fixed rate, irrespective to the cell
condition.
2- Their structure is simpler
Controllable genes:
1- Are expressed only as needed. Their amount may
increase or decrease with respect to their basal level in
different condition.
2- Their structure is relatively complicated with some
response elements
4.
5. Different ways for regulation of gene
expression in bacteria
1- Promoter recognition:
2-Transcription elongation( Attenuation)
6. OPERON in gene regulation of
prokaryotes
Definition: a few genes that are controlled collectively by
one promoter
Its structure: Each Operon is consisted of few structural
genes( cistrons) and some cis-acting element such as
promoter (P) and operator (O).
Its regulation: There are one or more regulatory gene
outside of the Operon that produce trans-acting factors such
as repressor or activators.
Classification:
1- Catabolic (inducible) such as Lac OPERON
2- Anabolic (repressible) such as ara OPERON
3- Other types
8. The activity of an Operon in the presence or
the absence of repressor
No repressor
With repressor
Figure 8.13
9. Lac OPERON an inducible Operon
In the absence
of lac
In the presence
of lac
10. CRP or CAP is positive regulator of Lac
and some other catabolic Operons
In the presence of lac +
glucose
CRP= Catabolic gene regulatory Protein
CRP= cAMP receptor Protein
CAP= Catabolic gene Activating Protein
11. Trp OPERON a repressible example
In the absence of Trp
In the presence of Trp
12. Attenuation by different secondary RNA structure
Starved: antitermination
Nonstarved: termination
16. Control at DNA level by - 1
DNA methylation
Heterochromatin is the most tightly packaged form of DNA.
transcriptionally silent, different from cell to cell
Methylation is related to the Heterochromatin formation
Small percentages of newly synthesized DNAs (~3% in
mammals) are chemically modified by methylation.
Methylation occurs most often in symmetrical CG sequences.
Transcriptionally active genes possess significantly lower levels of
methylated DNA than inactive genes.
Methylation results in a human disease called fragile X syndrome;
FMR-1 gene is silenced by methylation.
17. Control at DNA level by Histon - 2
(modifications(Chromatin Remodeling
•
Acetylation by HATs
and coactivators leads to
euchromatin formation
•
Methylation by
HDACs and corepressors
leads to heterochromatin
formation
18. Control at DNA level by gene -3
amplification
Repeated rounds of DNA replication yield multiple
copies of a particular chromosomal region.
19. Control at transcription - 4
initiation
By using different sequences (promoter, enhancer or silencer
sequences) and factors, the rate of transcription of a gene is controlled
gene X
promoter
gene control region for gene X
21. Alternative splicing: A Role - 5
in Sexual Behavior in Drosophila
a. In Drosophila courtship, the male behaviors include: Following,
Singing & …
b. Regulatory genes (fruitless= fru) in the sex determination
pathways control these behaviors.
c. Physiologically, the CNS (central nervous system) is
responsible for key steps in male courtship behavior.) (fruitless)
The sex-specific fru mRNAs are synthesized in only a few
neurons in the CNS (500/100,000). The proteins encoded by
these mRNAs regulate transcription of a set of specific genes,
showing that fru is a regulatory gene. Its expression seems to
be confined to neurons involved in male courtship
22. Control at mRNA stability- 6
• The stem loop at 3’end is an’ iron response element’.
• The stem loop is stabilised by a 90 kDa protein in the
absence of iron and protects the mRNA from
degradation.
90 kDa iron sensing protein ( aconitase)
Transferrin receptor
mRNA
AUG
UA
A
+ iron
Fe
Transferrin receptor mRNA
Degraded by 3’ nuclease
•
In the presence of iron, transferrin receptor
protein synthesis is reduced.
No iron :
mRNA is
translated
into
protein
+ iron
stimulates
23. Control at mRNA stability- 6
• A stem loop is stabilised by the 90 kDa protein in the absence
of iron.
• This time, the stem loop is at the 5’ end of the mRNA.
No iron
AUG
Ferritin mRNA
• The presence of the stem loop prevents translation of this mRNA
by blocking the progress of the ribosomes along the mRNA.
+ iron
Fe
AUG
UA
A
+ iron
stimulates
• In the presence of iron, the hairpin is lost, the ribosomes can
translate the mRNA and ferritin protein synthesis is increased.
24. Control at mRNA stability- 6
• Some hormones which enhance the production
of proteins also increase the half life of the
protein’s mRNA.
Estrogen : ovalbumin
>24hr
Prolactin : casein
to 92hr
t 1/2 from 2- 5hr to
t1/2 from
5 hr
25. Control at initiation of translation - 7
3’ UTR
5’ UTR
AUG
UAA
Specific sequences make specific secondary structures
Specific protein factors bind to these secondary structures
26. 8-Regulation by protein stability
•Ubiquitin-dependent proteolysis. Cyclins control of cell cycle.
• Protein molecule is tagged for degradation by attachment of a
20 kDa protein, ubiquitin
ATP
NH 2
NH 2
+
Doomed protein
molecule
CONH
COOH
ubiquitin protein
ligase
CONH
26S
proteasome
• The stability of a protein depends upon its N-terminal
amino acid (the N-end rule).
N-terminal : For example arginine , lysine : protein t1/2 =
3 min
N-terminal : For example methionine, alanine, : t1/2 >20
hrs.
27. Regulation by water soluble Hormones
Polypeptide hormones bind at the cell surface and activate
transmembrane enzymes to produce second messengers
(such as cAMP) that activate gene transcription.
29. Regulation by lipid soluble Hormones
Steroid hormones pass through the cell membrane
and bind cytoplasmic receptors, which together
.bind directly to DNA and regulate gene expression
Editor's Notes
For the iron (Fe 2+) transport protein transferrin receptor.
A stem loop structure in the mRNA acts as an iron response element and binds a 90 kDa protein in the absence of iron. The RNA and iron binding regions of the protein overlap so in the presence of iron the 90 kDa binding protein can no longer bind to the mRNA iron response element and the stem loop no longer occurs. Since the stem loop is at the 3’ end of the mRNA , the loop is stabilising of the mRNA , protecting it from degradation. In the presence of iron, the loop disappears and the mRNA is degraded by 3’ exonucleases.s
The binding of iron to the 90 kDa protein has opposite effects for ferritin. In this case, the stem loop is at the 5’ end. It inhibits translation by preventing ribosomes getting onto the mRNA and thus its disappearance stimulates transcription. Its removal leads to degradation of the mRNA and thus reduces translation.
mRNA stability. When milk protein synthesis is stimulated in the mammary epithelium at child birth, the rapid increase in casein level arising from the pituitary hormone prolactin results from increased transcription of the casein gene but also from stabilisation of its mRNA. In fact, the stabilisation of mRNA is an essential component of the rapid build up of casein protein and this sort of regulation is evident in many situations in which the production of a particular protein needs to be increased to a high level.
The mechanism is not well understood. The poly A tail protects the mRA from 3’ degradation. Histone mRNA (histones are produced during the DNA synthetic phase of the cell cycle) do not have a poly(A) tail and are unstable. The sequence of bases in the 3’ untranslated region, especially runs of As and Us can affect the stability of individual mRNAs. However, the enzzymes that break down the RNA are not well characterised.
Protein stability. Ubiquitin system.
20 kda protein ubiquitin is activated by ATP
It is linked by its C terminus to amino group on a lysine side chain in target protein.
Enzyme is ubiquitin protein ligase.
Up to 50 molecules of ubiquitin / target protein molecule.
Ubiquitinylated protein molecule then degraded by proteosome. A large multiprotien complex (2000 kDa)
The level of cell cycle regulatory proteins called cyclins are produced at the G1 to S phase boundary of the cell cycle. The proteins stimulate kinases which trigger DNA synthesis. Once this triggering has occurred, there is no further need for the cyclins and they are degraded by the ubiquitin system. This system allows for rapid removal of proteins. It is selective. Another method for degrading proteins, the lysozome is non-selective.
It was originally thought that breakdown of proteins occurred in the lysozomes. However, reticulocytes which do not have lysozomes still break down abnormal proteins. The system involves a 76 amino acid residue protein called ubiquitin, because it is widespread in eukaryotic spp. It is also one of the most conserved proteins known, differing in only 3 AA between human and fruit fly.
Attachment is to the C terminus of ubiquitin and this is transferred to the amino group of a lysine side chain of the protein. Many ubiquitins per target protein molecule.
Proteasome is a 20 s/u multi protein complexcontaining at least 5 different proteolytic activities in the shape of a bi-capped hollow barrel. UBIQUITIN IS NOT DEGRADED.