Lambda-lysis

Question 1

early lysis

Answer 1

if enough cro is present, the antiterm Q is produced; Q allows Pr’ to produce proteins leading to viral production;

Question 2

how does Q function in lysis?

Answer 2

unlike N, Q binds to qut sites on DNA, binds passing RNA pol, and increases processivity through a termination seq

Question 3

what is terminase used for?

Answer 3

cuts the genomes apart at the cos sites (12 bp overhangs)–>genome packed into viral heads & mature viruses are produced

Question 4

how does lysis occur?

Answer 4

Protein R produces endolysin which breaks down peptidoglycan walls; Protein S is a holin which accumulates within e coli cyto until a critical concentration is reached and then permeabilizes the membrane;

Question 5

late lhysis

Answer 5

Lambda-reactivation, UV induction; UV damage causes increase in RecA; it is a ssDNA binding protein but also can double as a protease (used to induce other repair pathways)–>RecA cuts lambda repressor cI bw the DBD and dimerization domains; absence of bound cI leads to N and cro production; leads to xis and int excising lambda from genome–? Q antitermination, DNA replication, viral assembly, and lysis

Question 6

cI’s job is to repress cro and induce lysogeny

Answer 6

ya