Unit 3: Regulating Transcription in Eukaryotes Flashcards
MCB 181R University of Arizona
What is required for transcription initiation (getting started)?
Getting the RNA polymerase inserted into the DNA at the start of the gene.
How is transcription initiation regulated?
By proteins binding to DNA sequences.
What is the role of the promoter in eukaryotes?
It’s a non-coding DNA sequences in front of the gene where general transition factors bind to help inter RNA polymerase.
What do general transcription factors do in eukaryotes?
They bind to the promoter and help insert RNA polymerase into the DNA at the beginning of the gene.
How do proteins “recognize” specific DNA sequences?
Different bases have different charges exposed in the DNA grooves. A protein with a complementary shape and pattern of charges will “fit” the DNA sequence and bind to it.
What is the RNA polymerase complex?
A group of proteins, including RNA polymerase itself, that assembles at the promoter to initiate transcription.
What is the mediator complex?
A protein complex that acts as a bridge between the RNA polymerase complex and regulatory transcription factors bound to enhancer sequences.
What is the role of general transcription factors in eukaryotes?
They are necessary transcription initiation, but not enough to control whether transcription actually Starts or how often.
What controls whether transcription gets initiated (and how often)?
Regulatory transcription factors.
What is positive regulations of transcription?
It increase transcription of a genes, turning it “on” or “up.”
What is negative regulation of transcription?
It decrease transcription of a gene turning it “down” or “off.”
How are both positive and negative regulation of transcription controlled?
By regulatory transcription factor proteins binding to special regulatory DNA sequences.
What are enhancers?
Noncoding regulatory DNA sequences that, when bound by matching regulatory reanscxiption factors, positively regulate transcription.
Where can an enhancer be located relative to the gene it regulates?
Thousand of base pairs away, either before or after the gene along the DNA.
What are different “flavors” of enhancers?
Different enhancers sequences that bind to different regulatory transcription factor proteins.
What happens if multiple genes have enhancers with the same sequences?
They can be regulated by the same type of transcription factor.
What are silencers?
Noncoding regulatory DNA sequences that, when bound by matching regulatory transcription factors, negativity regulate transcription.
Where is a gene’s silencer more likely to be located?
Closer to the gene and before it.
Are the there different “flavors” of silencers?
Yes, just like enhancers, there are different silencer sequences that bind to different silencer sequences that bind to different regulatory transcription factors proteins.
What is the general organizer of proteins to DNA to affect transcription initiation?
Proteins bind to DNA to affect transcription initiation.
What is combinatorial control?
The regulation of many genes by multiple enhancers and silencers, along with the regulatory transcription factors that bind to them.
What determines whether and how much a gene is transcribed under combinatorial control?
The particular combination of regulatory transcription factors present in the cell.
How does combinatorial control allow for more precise gene regulation?
By using different combinations regulatory elements, cell can fine-tune gene expression in response to various signals and conditions.
Can multiple genes be regulated by the same type of transcription factor?
Yes, if they share the same enhancer silencer sequences.
