Gene expression in eukaryotes - lecture 3 Flashcards
How can cell division result in potentially different daughter cells?
Certain genes , controlling the fate of the cell , can be turned on or off
5 main components of genome structure of eucarya
- nuclear membrane
- linear chromosome
- condensed chromatin by histones
- multiple replication origins
- single gene transcription
2 similarities between eukaryotes and prokaryote gene expression
- RNA polymerases allows transcription
- mRNA used
What does polymerase 1 transcribe?
rRNA (ribosomal)
what does polymerase 2 transcribe?
pre mRNAS , snoRNAS, some miRNAS , some snRNAS
What does polymerase 3 transcribe?
tRNAs, small RNAs, miRNAs , some snRNAs
3 differences between eukaryote and prokaryote gene expression regulation?
- eukaryotes : DNA must unwind form histones
- eukaryotes:transcription takes place in the nucleus
- Eukaryotes: one gene, one promoter
What is transcription regulated by?
transcription factors and transcriptional activator proteins
What is a core promoter?
The region where the basal transcription apparatus bind. Includes the TATA box
what is a TATA box?
type of promoter sequence
Enhancer
DNA sequence stimulating transcription from a distance away from promoter
silencers
elements where transcriptional repressors bind.
What does more binding sites lead to?
more transcription
What is the action of an insulator?
blocks the action of an enhancer on a promoter
How does transcriptional stalling speed up the transcription of genes?
- RNA polymerase can be stalled after the initiation of transcription
- When the right cue is present then transcription elongation blocks are released
