Transcriptional Regulation in Eukaryotic Flashcards
Compare Eukaryotic Gene regulation with prokaryotic regulation
Eukaryotic gene regulation involves a greater amount of DNA, mRNAs have to be spliced, capped, and polyadenylated, genes on numerous chromosomes are enclosed in a double membrane nucleus
Eukaryotic genes are situated on chromosomes that occupy a distinct location Eukaryotic D N A is combined with histones and nonhistone proteins to form chromatin
How are nucleosomes modified?
Involves a variant histone affecting nucleosome mobility. Nucleosome position can repress or activate transcription via gene promoter.
How histones modified?
Acetylation, methylation, phosphorylation.
What does chromatin modeling do.
Repositions or removes nucleosomes on DNA, making chromosome regions accessible to transcriptional regulatory proteins, transcription activators, and RNA polymerse II
What are transcription factories?
Nuclear sites that contain most of the active R N A polymerase and transcription regulatory molecules
Dynamic structures that form rapidly and disassemble upon stimulation and repression of transcription
What do core and proximal promoters do?
core promoters determine accurate initiation of transcription
proximal promoter elements modualte efficiency of basal levels of transcription
What are the cis acting transcription regulatory elements -
enhancers - helps max transcription occur
, insulators- allows some enhancer promoter interactions and blocks others
silencers- represses transcription initiation
what are the functional domains of transcription factors-
dna binding domain (binds in cis acting site) and trans activating domain (activates or represses transcription by binding to other transcription factors or RNA polymerase)
Describe the RNA pol II initiation complex -
required for promoter to initiate basal or enhanced levels of transcription, requires proteins to form pre initiation complex, which provides platform for RNAPII to recognize transcription start sites.
What do coactivators do?
interact with proteins and enable activators to make contact with promoter bound factors, forms enhanceosome
What are promoters made up of
Initiator region, TATA box, TFIIB recognition element, DPE, motif ten element
What do transcription factors do?
They function as transcription regulatory proteins and target cis acing sites of genes regulating expression.
They can be activators or repressors
What are the domains of DNA binding proteins
Helix turn helix- present in both eukaryotic and prokaryotic transcription factors
Zinc finger - found in wide range of transcription factors that regulate gene expression
Basic leucine zipper - allows for protein-protein dimerization
What is TFIID made up of
includes TATA binding protein and several TBP associated factors
What does DNA looping do
delivers activators, repressors, and general transcription factors to promoter vicinity
