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imissyou419's version from 2016-12-20 17:00

Section

Question Answer
What are the different regions of the genome?genes (introns, exons), promoters, enhancers (promoters and enhancers tell gene "when" "where" "how much"), intergenic regions
Enhancerscan be upstream or downstream, can be on different chromosomes (trans-regulation), "position" independent (within reason), affect DNA folding and interactions
Is central dogma true?No, RNA can make DNA
Promotersposition fixed - upstream (5') of the Transcriptional State Site (TSS), generally 150-500 bp in length, contains DNA sequence TATA/CAAT, proximal control element such as TFIIB recognition element (BRE) and initiator sequence (INR), binds general (basal) transcription factors, may bind tissue specific transcription factors
What is important about 5' G-CAP and 3' polyA tail?increases translation because stabilize mRNA
TFIID functionbinds to core promoter region and starts process
TFIIA and TFIIBstabilize TFIID binding, TFIIB recruits RNA pol II (inactive)
what transcription factors are associated when a gene is primed?TBP, TFIID, TFIIA, TFIIB
TFIIF binds what?RNA pol II and TF IIB which helps in recruitment of RNA pol II
TFIIEstabilize complex
TFIIHhelicase activity help unwind promoter region, activate polymerase to begin RNA synthesis, phosphorylate RNA pol II so it is released and get transcription
DNA is wrapped aroundhistone protein complexes, allow for more efficient packaging, regulation of gene expression, and interaction b/w distant regions of DNA -> forms nucleosomes
Nucleosomes bind to ____ to organize into larger looping structuresnon-histone scaffolding proteins
insulator regionsprevent conversion of euchromatin to heterochromatin so viruses can integrate their genome anywhere

transition from active nucleosomes to repressed nucleosomes (CTCF boundary - cofactor)
DNA looping bring enhancer and promoter regions together to regulate gene expression
Coactivators/corepressorscoactivators are transcriptional factors that BIND PROTEINS and bring them closer together (co-repressor separates them); binding of co-activators or co-repressors to the same gene will regulate expression from a distance
Coactivator exampleNRF-1, enhance expression by increasing protein interaction
Corepressor exampleHeterochromatin proten 1 (HP1a), prevent protein interaction
Chromatin is _____ distributed within the nucleus in interphasenon-randomly, distribution is cell type specific, LADs bind to lamin associated proteins and repress gene expression (accumulation of heterochromatin at periphery and accumulation within @ nucleolus), because it is mechanism for coordinated gene expression
Give an example of coordinated gene expressionhaemaglobin expression needs 2 chromosomes with genes that must be transcribed in parallel so transcription of 2 haemoglobin genes localized to same area within nucleus (enhancer is enhancing both genes) - coordinate expression of same gene in same pathway to conserve energy and rapidly respond for things that require multiple components
X inactivation coordinated gene expressionin humans, second copy of X inactivated; in other species, those genes appear on different chromosomes so brought into close proximity to be silenced
Reporter geneseasily detectable, not normally expressed in cells or tissues to be analyzed, not quickly degraded, not subject to post-transcriptional or post-translational regulation, e.g. GFP, luciferase, b-galactosidase
Luciferase promoter reporter assaysemission of light, stable, does not affect cells, QUANTIFIABLE (detect quantity of light to see how well promoter works when you take out certain regions), does not work in vivo
lacZ promoter reporter assayvery stable, easily detectable, in vivo analysis; can see promoter is working by change in colour to pancreatic protein because b-galactosidase expressed everywhere Pancreatic protein A is expressed (very specific to that promoter i.e. pancreatic promoter)
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