week 1 Flashcards
does binding of TBP SU of TFIID (recognizes TATA box) onto the core promoter require TATA box site?
NO
–TBP is part of multi protein complex– TAF for example of TFIID, can recognize non TATA box sites of core promoter
which eukaryotic RNAP is responsible for transcription of all protein coding genes?
RNAP II
Bacterial RNAP holoenzyme is composed of what two structure?
- sigma factor— recognizes consensus sequence of promoter/terminator
core polymerase enzyme— polymerase activity
how is transcription elongation coupled to RNA processing?
phosphorylation of RNAP CTD tail by TFIIH initiates elongation
ALSO
–upon its phosphorylation– acts as a scaffold to bind/tether processing proteins which “Hop” from RNAP tail to nascent emerging RNA transcript
During pre-spliceosome assembly (ATP required process) describe the proteins that bring intron ends into close proximity?
- U2AF
- SF1/BBP
- ASF/SF2 (SFRS1)
U2AF- U2 snRNP binding to branch point
SF1/BBP- splice factor– branch point binding protein
ASF/SF2- alternative splicing factor
marked characteristics of intron consensus sequence
- what bases at beginning of 5, end of 3 prime?
5 prime– beginning of intron seq– GU
3 prime– end of intron seq— AG
Effect of Exon splicing enhancers (ESE) on exon definition?
- what is it rich in? what splicing factor is it bound by?
- what happens if an ESE sequence remains unbound at its 3 prime end?
ESE– increase exon definition i.e. prevent it from being spliced out
- purine rich– recognized by SR proteins
absence of splicing factor—> no exon definition/ hence a weak 3 prime splice site— exon is skipped
how do Intron splicing silencers inhibit exon definition?
binding of PTB to ISS sequences that flank exon– exon is skipped
outline the positive and negative control and how their regulation of AS events affects protein production
- Negative control– repressor binding /weak splice site
Positive control– promoter binding/ strong splice site
both alter gene expression— hence protein production
