Chapter 7: Control of Gene Expression Flashcards
this is a series of genes (often in sequence) that are all under regulatory control; they include separate functional proteins that work together
operon
lac operon – glucose and lactose both present
off
lac operon – glucose present no lactose
off
lac operon – no glucose or lactose
off
lac operon – no glucose yes lactose
on
in what conditions is the lac repressor protein present on the lac operon?
low levels of lactose
in what conditions are cAMP and CAP present on the lac operon?
no glucose
this is a protein in the lac operon that binds to cAMP at low glucose levels to interact with promoter sequences
CAP (catabolic activator protein)
what promoter sequence does CAP interact with in the lac operon?
cis-regulatory promoter sequence
What are 3 typical regulatory sequences found in a eukaryotic gene?
- TATA box
- transcription regulators
- cis-regulatory sequences
these sequences bind regulators and coactivators to regulate gene expression
ex. specifically interacts with CAP
cis-regulatory sequences
Why are so many control points needed to regulate gene function? (3)
- prevents unnecessary energy spending
- induces proper response to conditions
- allows expression/protein coordination
What are 3 ways eukaryotic repressor proteins influence gene expression specifically on the DNA/transcription level?
- binds directly to DNA (blocks RNA pol)
- inactivates activator sequence
- direct interaction with transcription factors
What are 3 proteins that eukaryotic repressor proteins recruit at the histone level to regulate expression?
- chromatin remodeling proteins
- histone deacetylase
- histone methyl transferase
the probability of transcription initiation is ______?
the summation of inhibition/promotion signals
