BG 3 lysogenic bacteriophage

lysogenic does not have a ____. it does what

phage. replicates with chromosome and all daughters get it

lambda lysogenic dna enters cell through ___ sites or ____ between ends

cos sites, pairing

cos sites

complementary 12 bp sticky ends which can join and make a circle

lambda requires products of 2 genes for replication

o and p

o protein

bends dna at ori to initiate replication

p protein

binds to O and dnaB

Gam in replication

indirectly shifts to rolling circle rep

recBCD nuclease

inhibits rolling circle rep

transcription antitermination

trasncription starts at promoters and terminates unless conditions are met

which proteins are required for transcriptoin termination to decrease or be inhibitied

cro, n, nutR, nus proteins

order the n proteins in antitermination complex

nutR —> nus proteisn —> n protein

lysogenic cells are immune to ____, so they form what in center of plaque

superinfection, cloudy appearance

what causes plaques to be clear

mutations in c1, c2, c3

how can lysogenic host cells be immune to superinfection

cl repressor is in the host genome, and when a new phage infects it, it takes it up and keeps it in the lysogenic cycle

c2 is a ___ that activates

transcriptional activator, rna polymerase

c3 ____ c2, and no ____ form

inhbits, lysogens

Int is a

site specific recombinase that promotes integration of lambda dna

int promotes attachment between ____ and _____ through sites

phage, bac

what is attp and attb

attachment sequence for phage and bacteria

during lysogeny, ____ is one of teh few lambda genes transcribed

cl repressor, which binds to two operators

cl can be a ___ or ___ depending on where it binds operators

repressor activator

the two operators, ___ and ____ are close to two promoters.

Or and Ol

the cl repressor bound to the operator represses the ______, keeping the phage in the genome

lytic cycle and transcription of most other lambda genes

in the prophage state, what is the cl gene transcribed from

the Prm (repression maintenence) rather than the Pre promoter

2 domains of Cl polypeptide

promoters formation of dimers and tetramers, binds to operator

for Cl to function, it has to

dimerize

cl dimers form at

high concentrations

the operator has ____ supressor sites

3

if Cl is low, ____ is occupied and suppresses Promoter R which prevents replication of ___ and ___

Or1, O and P

if Cl increases, the _____ becomes occupied, ____ form, and Cl can activate _______

Or2, tetramers, transcription of Prm promoter

if cl concentration is very high, ____ is occupied, transcription of ____ is blocked

Or3, Prm

affinity of cl repressor for sites Or and Ol

Or1 > 2 > 3, same with Ol

cl repressor prevents transcription of any other ______ infecting the lysogenic cell. that makes them ____

lambda phage, immune if phage does not have different operator regions

lambda phage remains in the prophage state until _____, which

the cell is severely damaged, this induces the lytic cycle

what is induction of lambda

swhitching from lysogenic to lytic

the cell that repairs dna damage has dna that binds to ______, which binds to the _____ causing it to cleave itself

recA, cl repressor

if cl repressor is cleaved, it can’t ___ and dna binding domains cannot

dimerize, bind to operators

why can’t lysogenic phage just make more cl repressor? what is stopping it after induction?

Cro

cro binds to operators in ______ whcih prevents cl from promoting its expression

reverse order

when cro prevents cl from binding, ___ and ____ are synthesized

Int and Xis

xis helps with

excision of the lambda genome

after initial infection, there is no ______. two genes are transcribed

cl repressor. n and cro genes

the n gene allows transcription of genes including which 4

c2, c3, rep of O and P

whether the cell becomes lytic or lysogenic depends on a race between

c2 activator protein and cro protein

the race is determined by ____ but it’s influenced by metabolic state of host cell

MOI