Lecture 6 Flashcards
What is Transcriptional regulation?
regulation of gene expression by transcription factors
What is Post-transcriptional regulation?
regulation occurs at the level of the RNA
What is Co-transcriptional?
the RNA is still associated with the RNA-polymerase
What is Post-translational regulation?
regulation occurs at the level of protein
Where does the processing of eukaryotic Pre_mRNAs take place?
Co-transcriptionally
What is special about the C-terminal domain of RNA Poly II
Can be post-translationally modified
What are functions of the CTD of RNA Poly II?
Capping, Splicing, poly-A recruitment
What are charatceristics of the Cap?
Methylated guanine base
Nucleotides 1 and 2 of mRNA are also methylated
methylation helps escape immune response
every mRNA has a cap
Why is the Cap important?
Recognized by Cap binding proteins
needed for efficient translation
Prokaryotic mRNA dont have a Cap (Shine dalgarno)
How does the Cap bind ?
By interaction of two aromatic residues
How do viruses (who cant synthesize a Cap escape detection)
By Cap snatching
How does maturation of mRNA at the 3´ end take place?
- Cleavage
- Poly-A tail attatchment
What are functions of the Poly-A tail?
export from the nucleus
tranlation
degradation
What is alternative polyadenylation?And what benefits/detriments could it have?
genes with more than 1 poly-A cleavage site (differ in lengths of untranslated regions)
benefits: increased DNA stability (APA mRNA less susceptible to microRNA degradation)
localization and translation efficency are also affected
