Eukaryotic transcriptional regulatory elements and RNAP Flashcards
What is the extent of transcriptional regulatory elements in prokaryotes?
Conserved consensus sequences in the core promoter that RNAP binds to and are necessary to initiate transcription. Enhancers are extremely rare and only used for sigma54 factors
Do eukaryotes also have conserved consensus sequences in the core promoters?
Yes, but they aren’t sufficient to initiate transcription on their own. The sequences are less conserved and more diverse in eukaryotes too
What defines how a eukaryotic regulatory element is defined?
How close they are to the core promoter
What are proximal promoter elements?
Regulatory elements that are close upstream to the core promoter
What usually binds to proximal promoter elements?
Transcriptional activators, and sometimes repressors
How important are proximal elements?
Very important. Have to be bound by TFs for any measurable transcription to occur
What are distal regulatory elements?
Regulatory elements that are much further upstream to the core promoter
What types of regulatory elements are considered to be distal elements?
Locus control elements, insulators, silencers, enhancers
How do distal elements make contact with the core promoter when they’re so far away?
DNA looping
What do enhancers do?
Activate gene expression
What do insulators do?
Protect the promoter from regulatory events
What do silencers do?
Repress gene expression
Are distal regulatory elements always upstream of their target genes?
No, can also be downstream or in an intron
Is it more common for a gene to be regulated by a single enhancer or multiple?
Multiple
Why are enhancers so important during events like development?
The combination of enhancers acting on a gene dictate where and when a gene gets expressed. The combination of activated enhancers dictates which tissue the gene gets expressed in
