Lecture 38 Flashcards
(27 cards)
How many genes do eukaryotes have?
21,000 genes
What are regulatory proteins in eukaryotes?
transcription factors that bind to DNA and control rate of RNA Pol transcription
What is true about TF’s and their expression?
they are expressed tissue-specifically and some respond to outside signals
What are the core promoter regions in eukaryotes?
the initiator, TATA box, and downstream promoter
What are the upstream promoter regions in eukaryotes?
CAAT box and the GC box, both regulatory elements
What are some examples of eukaryotic promoters?
thymidine kinase and H2B
What are enhancers?
activators
What are silencers?
repressors
What to enhancers and silencers do?
They can increase gene expression or inhibit transcription by 200x
What is true about enhancers and silencers?
They have short control sequences that bind to TFs, are tissue specific, have great distances from promoter and different polarity
How do TF’s influence transcription?
How was TF influence on transcription found?
Studying yeast and it was found that at the vitro level a transcription complex worked at the basal level
What is the function of mediator complexes?
to transmit signals from the transcription factors to the polymerase
Wht do mediators function as?
transcriptional coactivators
What do mediators do?
linking upstream regulatory sequences, such as enhancers, with RNA Pol II and general transcription factors at the promoter region
What is required for a successful transcription by RNA Pol II?
mediator complex
What do transcription factors respond to?
steroid hromone, cAMP transcription, cell signaling
What affects accessibility of DNA to RNA Pol and TFs?
histones and chromatin also known as chromatin remodeling
What is the purpose of chromatin remodeling?
expose the promoter region for the transcriptional process
What makes up a nucleosome?
octamer histone core with DNA wrapped around it
What are histones?
proteins that contain N and C terminal domains
What is the N tail responsible for?
specific histone modifications and regulation of nucleosome activity takes place
What is the histone fold domain responsible for?
where histones fold and interact with each other and mediation of the heterodimerization of histone pairs occurs
