eukaryotic gene expression Flashcards
what does RNA pol II do?
- recognizes and transcribes structural genes
- recognizes core promoter
- recognizes CAAT box at -75 and -100
- recognizes GC boxes
- recognizes enhancers
what are structural genes
genes that encode proteins
what is included in the core promoter
- initiation site at +1
- TATA box at -30 (in eukaryotes)
where is the TATA box in eukaryotes and where is it in prokaryotes?
-30 in eukaryotes
-10 in prokaryotes
define cis and trans
cis: stationary
trans: moves to where it’s needed
what are the basal factors?
TBP - TATA box-binding protein
TAF - TBP-associated factors
what are transcriptional activators
bind to enhancer sequences to increase the rate of transcription
most eukaryotic activators must form ________ to function
dimers
what are transcriptional repressors
they diminish transcriptional activity by
competition - bind to enhancer to prevent enhancement or
quenching - bind to the activator
repressors are __________-dependent
concentration
why is transcription passively minimized in eukaryotic cells?
because of the structure of chromatin
how can gene expression be governed?
- altering chromatin structure
- altering DNA methylation patterns
what is euchromatin
less condensed, more easily transcribable DNA
what is heterochromatin
large areas of chromosomes that are silenced (permanently off)
what are TADs
topological associated domains - they form loops of chromatins between promoters and enhancers that are far apart, and brings them closer together so they can interact
