BIOL 200 Lecture Notes - Lecture 10: Elongation Factor, Polyadenylation, Nucleosome

• School: McGill University
• Department: Biology
• Course: BIOL 200
• Professor: Kenneth Hastings

Document Summary

Lecture 10 tra(cid:374)s(cid:272)riptio(cid:374) i(cid:374)itiatio(cid:374) a(cid:374)d elo(cid:374)gatio(cid:374) a(cid:374)d 5" pro(cid:272)essi(cid:374)g: transcription initiation. In most animals promoters, pol ii pauses after transcribing <100bp. This facilitates the re(cid:272)ruit(cid:373)e(cid:374)t of the 5" (cid:272)appi(cid:374)g e(cid:374)z(cid:455)(cid:373)e (cid:272)o(cid:373)ple(cid:454) that sta(cid:271)ilizes the 5" e(cid:374)d of the (cid:374)as(cid:272)e(cid:374)t message. This is the final check-point, after this point the elongation will not stop anymore. Model of promoter proximal pausing and release: pol ii initiation and entry into the pause site, pol ii pausing by negative elongation factor (nelf) and drb-sensitivity inducing factors (dsif) occurs. This is facilitated by the core promoter elements and +1 nucleosome. (cid:1007). 5" (cid:272)ap pro(cid:272)essi(cid:374)g happe(cid:374)s: positive transcription elongation factor-b (ptefb- kinase protein) mediates release of paused. Pol ii by phosphorylating (orange circle) nelf, dsif and the ctd of pol ii: dsif becomes a positive elongation factor after phosphorylation, and removes from the pol. Elongation is highly processive (never stops) once it begins. However, rna pol ii can move through some regions faster than others.