control of gene expression in eukaryotes Flashcards
T or F: eukaryotes use activators and repressors
true
T or F: the mechanism for regulation of gene expression in eukaryotes is the same complexity as it is in prokaryotes
false; the mechanism in eukaryotes is much more complex than in prokaryotes
why is transcription regulation more complex in eukaryotes
the cis-regulatory sequences of regulators are spread over longer stretches of DNA called gene control region
what is a gene control region
a region that contains the info for transcription regulation
do transcription regulators appear alone or in groups
in groups
for transcription regulation, do we need few or many regulators
many
other than GTFs and regulators, what type of intermediate proteins are involved
coactivators and corepressors
T or F: coactivators and corepressors bind to DNA
false, they bind to the activator or repressor
what two models were initially proposed to answer how cis-reg sequences play a role in regulation if they’re so far from the promoter
scanning model
DNA looping model
describe the DNA looping model in transcription initiation
direct interactions between regulators bound at cis-reg sequences and the distant promoters were proposed to stimulate RNA pol
describe the scanning model in transcription and initiation
RNA pol (or a regulator) was proposed to bind at a regulatory sequence and then slide along DNA until it reached the promoter
describe the experiment that was done to determine which model was true: scanning model or DNA looping model
used a cis-reg sequence on one piece of DNA and a gene with its promoter on a separate piece. The gene was not expressed when the pieces were separate. When linked with a protein linker, the gene was still not expressed because it got in the way of RNA pol, therefore DNA looping is true and scanning is not
where do activators bind
cis-reg sequences called enhancers
are enhancer sequences long or short
long
how long are enhancers
50-200 bp
