lecture 1 - Control of transcription and chromatin Flashcards
what is gene expression
the process by which information in genes (DNA) is decoded into protein
what is A in mRNA
U
what on the RNA pol binds to the DNA promoter
sigma 70
once RNA pol has gained access to the template
sigma factor is released
what type of enzyme is RNA polymerase
holoenzyme
what does the promoter dictate
where transcription starts an how efficient it is
points that are upstream of the transcription start site are given a
negative number
eukaryotic basal promoter elements have
TATA box (-31 to -26)
initiator (-2 to +4)
CpG islands
regions with high frequency of CG sequences
c residues in CgP islands escape methylation
if Cpg islands are methylated the gene is switched off
UAS and enhancer
activator binding sites, increase transcription
URS and silencer
repressor binding sites, prevent transcription
general transcription factors
TFIIA
TFIIB
TFIID
TFIIE
TFIIH
TFIIF
what do they do
form a complex on the TATA box, recruit RNA pol II to the promoter, direct initiation as start site
TFIID binds to the TATA box and allows TFIIA and B to join
TFIIB signals recruitment of RNA pol II which brings TFIIF with it
final joining of the TFIIE and H
transcription initiation by RNA pol II
helicase activity TFIIH separates the template strand at the start site - requires ATP
TFIIF moves down the template with pol II
