#Question id: 4485
#Unit 3. Fundamental Processes
In multicellular organisms, regulatory sequences can spread thousands of nucleotides from the promoter—both upstream and downstream—and can be made up of tens of regulator binding sites. Often, these binding sites are grouped in units called_?
#Question id: 4486
#Unit 3. Fundamental Processes
Activators can recruit factors needed for polymerase to initiate or elongate transcription. In all of these functions, the activator is merely recruiting proteins to the promoter. In bacteria, RNA polymerase is the only protein that needs to be recruited; this is not the case in eukaryotes. Indeed, in eukaryotes, a given activator might work in all three ways:
|
1. Recruitment of nucleosome modifiers and remodelers |
i. “open” the promoter |
|
2. Recruitment of general transcription factors and mediators |
ii. That stimulate Pol II initiation and elongation |
|
3. Recruitment of protein complexes |
iii. To recruit PTEFb/SEC |
#Question id: 4487
#Unit 3. Fundamental Processes
Choose correct statements about nucleosome modifiers
#Question id: 4488
#Unit 3. Fundamental Processes
One component of thecomplex bears bromodomains and thus binds to acetylated nucleosomes better than to unacetylated nucleosomes. Thus, a gene bearing acetylated nucleosomes at its promoter will likely have a higher affinity for the transcriptional machinery than one with unacetylated nucleosomes.
#Question id: 4489
#Unit 3. Fundamental Processes
HSP70 gene from Drosophila. This gene, activated by heat shock, is controlled by two activators GAGA binding factor and HSF,In response to heat shock, HSF binds to specific sites at the promoter and recruits a kinase, P-TEFb (positive transcription elongation factor). What is the proper mechanism of pausing and release of Pol II ?
#Question id: 4490
#Unit 3. Fundamental Processes
The human immunodeficiency virus (HIV), which causes AIDS, transcribes its genes from a promoter controlled by P-TEFb (and SEC). Again, polymerase initiates transcription at that promoter, under the control of which activator?