Regulation of Gene Expression Flashcards
What level gene regulated?
1) Transcript present?
2) Transcript structure?
3) Protein expressed?
Transformer gene
- female development
Male = off Female = on
- transcript in both
- translated only in females
- females = splicing –> transcript
- males = stop codon –> no transcript
Regulatory Sequence
Bacteria
- Positive = activator
- Negative = operator
Eukaryote
- Positive = enhancer
- Negative = silencer
Promoter
Promoter = (+) prokaryote (-) eukaryote
Promoter & operator = (-) prokaryote (-) eukaryote
Promoter & activator = (+) prokaryote (+) eukaryote
Promoter, operator, activator = (-) prokaryote (-) eukaryote
LacZ and Laci
Laci has diffusible factor = trans-acting to LacZ
Operator LacZ recognize diffusible factor = cis acting to LacZ
Complementation Test
Mutations in different genes
- trans acting
Mutations in same genes
- cis acting
Intragenic Analysis
- operator constitutive dominant to lacZ loss of function in trans
- wild type alleles dominant when operator constitutive and lacZ loss of function in cis
Transcription Activators
binds to enhancer and silencers
- activate transcription
Sex Lethal Protein
- blocks use of male 3’ ss
- alternative splicing
- only females have this protein
- males have no sex lethal protein – stop codon
Nanos
- suppresses HB protein expression
- nanos null = expression
- binds to pumilio
Pumilio
- suppresses HB protein expression
- binds to nanos regulatory element