MBIO 4600 Lecture Notes - Lecture 21: Lysogenic Cycle, Bacteriophage, Repressor

• School: University of Manitoba
• Department: Microbiology
• Course: MBIO 4600
• Professor: Brassinga Ann

Document Summary

Linear dna in head but cyclizes after infection. Pairing of cos sites (ssdna of 12 nt) at ends and ligation. Temperate phage (can choose between lytic or lysogenic cycle) Immediately after infection: activation of two promoters: pl and pr, short rnas synthesized due to termination site. N protein permits rna polymerase to bypass transcription termination sites. Aided by host proteins nusa, nusb, nuse, and nusg. Nutl = n utilization leftward: n protein binds rna polymerase allowing transcription through termination site tl1. Bi-directional (i. e. theta) replication for a few rounds. Initiation of rolling-circle replication similar to that of m13: one strand cut to provide free 3" end as a primer, difference is continuous replication concatemers. Cos sites flanking 2 -genome length pieces cut and packaged. Recall activation of pr and pl and antitermination mechanism: transcription of o, p, q, gam, and red genes, o binds at ori site (=dnaa, o bound by p (=dnac) recruiting dnab, rna synthesis at pr.