Physiology 3140A Lecture Notes - Lecture 26: Rna Virus, Coding Region, Intron
2 May 2018
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Cell Physiology Lecture 26
Transcription 1
November 24 2017
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1. Makeup of the genome
2. Promoters and enhancers
3. General transcription factors
4. Genome organization
5. Transcription factor families
6. Regulation of transcription factors
What are the different regions of the genome?
- 3 parts of the gene; exons, introns, untranslated regions
- 5’ and 3’ untranslated regions not introns or exons
o PART RNA THAT IS MADE THAT DO NOT GET MADE INTO PROTEIN
- Coding and non coding DNA
o Non coding DNA = outside or between the genes
▪ May not made protein, but it will make RNA (almost in the entire genome, RNA is
being made)
o Coding = codes for protein
- Promoter (upstream; 5’ of the gene
- Enhancers:
o Involved in gene regulation
o A lot of genetic mutations (most) affect the enhancers
▪ Lead to development defect, susceptible to diseases
▪ May think that the mutation occurs in the gene region to ruin the protein BUT most
mutations are impacting the enhancers
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o Promoters are close to the gene, enhancers can be anywhere (all over the place)
▪ Tell you where and when the expression is going to take place
o Enhancer involved in saying when the gene is going to be on
o The gene itself does not tell where it is going to be expressed
▪ Can take another gene that does something different, for ex. A limb instead of eye
color. The gene is going to be expressed where the promotor and enhancer for the
eye are being told to express it.
o The promoter and enhancer are what tells where the gene is going to be expressed
- Intergenic regions – garbage, regulatory, regions, transcribed areas
- THEREFORE, 4 DIFFERENT REGIONS:
o 1. Genes – introns and exons
o 2. Promoters
o 3. Enhancers
o 4. Intergenic Regions
- Note: Promoters and Enhancers tell the gene when, where, and how much
DNA to RNA to mRNA
- Gene is made up of introns + exons
- Introns in blue, exons in green, untranslated regions in white
- CENTRAL DOGMA: GENE RNA PROTEIN
o DNA to RNA = transcription
o RNA to PROTEIN = translation
o Have found out that:
▪ Get DNA encoded from RNA; from RNA Virus
- Promoter upstream causes expression of the gene from the transcriptional start site
- Have start + stop codons
- Coding region is green; codes for protein
o All the other things regulate where it is expressed, how it is expressed and regulate the
stability of RNA
▪ All of them have an impact on transcription
o (ave the mRNA with 5’ UTR (untranslated region) coding green and 3’ UTR
- Introns get spliced out
- Poly A tail: prevents degradation of mRNA or enhances the stability of the mRNA
o Without it, you get RNA rapidly degraded. It is very rapid because RNA even with the Poly A
tail is still degraded quickly
- 5’ CAP: helps in translation
o Increases expression of protein from this region
- MATURE RNA:
o 5’ CAP
o 5’ UTR
o 3’UTR
o CODING REGION
o POLY A TAIL
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Promoters
- Tells the gene where and when
- Sequences in the promoter recruit polymerases required to make RNA – general
- Differences: not every gene is on all the time or expressed everywhere in the body there has to be
specificity
o Specificity comes from the: enhancers + promoters
- Promoter is position-dependent + orientation-dependent
o It has to be in the right place and sequence
- Position is fixed – upstream 5’ of the Transcriptional Start Site TSS
- Generally 150-500 bp in length
o Promoters are not very long
- Contains the consensus DNA sequences TATA/CAAT
o In 70% of promoters
o There to bring proteins required for transcription. The sequence brings in some of the
protein
- Proximal control elements such as TFIIB recognition element (BRE) and initiator sequences (INR)
o INR is right upstream (22 bases) of the transcriptional start site – where you identify that it
is promoter
- Binds General (Basal) Transcription Factors
- May bind tissue specific transcription factors (12-14k transcription factors that are tissue + time
specific)
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Transcription: makeup of the genome, promoters and enhancers, general transcription factors, genome organization, transcription factor families, regulation of transcription factors. 3 parts of the gene; exons, introns, untranslated regions. 5" and 3" untranslated regions (cid:523)not introns or exons(cid:524) The gene is going to be expressed where the promotor and enhancer for the eye are being told to express it: the promoter and enhancer are what tells where the gene is going to be expressed. Intergenic regions garbage, regulatory, regions, transcribed areas: 1. Note: promoters and enhancers tell the gene (cid:498)when(cid:499), (cid:498)where(cid:499), and (cid:498)how much(cid:499: 2. Gene is made up of introns + exons. Introns in blue, exons in green, untranslated regions in white. Central dogma: gene rna protein: dna to rna = transcription, rna to protein = translation, have found out that, get dna encoded from rna; from rna virus. Promoter upstream causes expression of the gene from the transcriptional start site.
