28 - HIPFNER 2 Flashcards
how does the Is mutation work
the Is repressor cannot bind the inducer
how do mutations of the LacI repressor work?
ie what happens in the expression of beta galactosidase and permease when there is vs isn’t any lactose
that is how they figured out that the repressor was a protein: it acts in trans so it can move
can act on the other DNA strand where the lac I is mutated
how is the lac operon also under positive regulation
glucose levels regulate cAMP levels
when high glucose=no cAMP
when no glucose=cAMP present
cAMP binds CAP (catabolite activator protein) coded by the crp gene
CAP-cAMP binds the promoter upstream of RNA pol and increase transcription
when you have no glucose you need more beta gal activity to get more glucose from lactose
what is the organization of the lac control region
what happens when:
glucose yes lactose no
glucose yes lactose yes
glucose no lactose yes
what is chromatin
DNA + associated proteins
heterochromatin vs euchromatin
what are the cis and trans acting factors in transcription initiation in eukaryotes
characteristics of enhancers
needed for the transcription regulation of cell and tissue specific genes
what are specific TFs and how do they work
characteristics of transcription factors and cofactors (their domains and structures)
what is the enhanceosome
enhancer bound transcription factors help recruit RNA pol II to the promoter
how do we test for the presence of enhancers in DNA?
cut pieces and hook them up before a reporter gene
measure activity of reporter gene
more reporter gene=likely an enhancer is there
Pax6 enhancer as an example of complex regulation of transcription in eukaryotes
Pax6 is transcribed specifically in only certain tissue types (eye, pancreas, brain) at only specific times of development
most cells never express it
from 0 to -8kb: this region only drives the expression of this gene in the eye (lens precursor) and the pancreas
from exon 4 to 5: only expressed in the eye
there must be a pancreatic TF and an eye TF that bind different enhancers that regulate PAX6 expression in specific tissues
