BIOL 200 Lecture Notes - Lecture 3: Ribosomal Rna, Transfer Rna, Regulatory Sequence
Document Summary
Post-translational regulation: phosphorylation (most common), histone modification (acetylation, methylation) Protein degradation control: gets recycled into its original component. Major ways to control gene expression: chromatin remodeling control access to genes, transcription factors (eukaryotes, rna (cid:373)odifi(cid:272)atio(cid:374) i(cid:374) (cid:374)u(cid:272)leus (5" (cid:272)appi(cid:374)g, 3" poly-a tail, intron/exon splicing) Usually you do(cid:374)"t o(cid:374)ly ha(cid:448)e o(cid:374)e (cid:373)odifi(cid:272)atio(cid:374) (differe(cid:374)t (cid:272)o(cid:373)(cid:271)inations) Allows signalling for proteins to come to specific area (for unpacking/packing) Acetylation makes dna less able to bind to histone octamer, so it is more likely to fall off. Active genes need access: nucleosome destabilization (more open configuration so that transcription factors can bind) Bind to promoter region before rna pol. Activator proteins bind to regulatory sequence (enhancer) upstream of the promoter. Once transcription has started, it usually goes to completion rna pol does not fall off halfway. Chromatin remodelling happens right before to allow access. Rna is more unstable than dna because it is readily accessed by rna nucleases.
