Eukaryotic Transcription Regulation Flashcards
what determines the startpoint for transcription?
basal apparatus
what determines the frequency of transcription?
activators
coactivators
connect activators to basal factors
- some have HAT activity and connect to SWI/SNF complexes
how do repressors work in eukaryotes?
- sequestered in the cytoplasm
- concentration driven by competition
what is the role of DNA-binding domains?
to bring the transcription-activation domain into the vicinity of the promoter
- DNA binding activity and transcription-activation are carried by independent domains of an activator
transcriptional activation motifs
make contact with basal factors and recruit them to the promoter
heat shock factor DNA binding domain
- histone H1
- helix turn helix
helix-turn-helix
triple helical cluster reinforced with beta strands
- antennapedia phenotype
basic leucine zipper proteins (bZIP)
coiled-coil dimerization domain plus a basic DNA interaction domain
- GCN4
basic helix-loop-helix (bHLH)
involved in differentiation of muscle cells
zinc containing DNA binding domains
- zinc fingers
- bimetal thiolate cluster
- nuclear receptors
zinc fingers
Cys2-His 2 coordinated by a single zinc ion
- Zif268
bimetal thiolate cluster
2 zinc ions coordinated by 6 cysteines
- GAL4
nuclear receptors
- steroids and related horomones
- bind ligand to activate
- 2 zinc molecules with 4 cysteins
- gluccorticoid receptor
why do nuclear receptors have 2 zinc modules?
one for DNA interactions and the other for dimerization