Micro exam 2 virus genome ssRNA(+)

if virus genome ssRNA(+) that means

the virus carries an mRNA like molecule

Bacteriophage MS2

"sex-specific"
- interacts with ecoli with F-pilus

Bacteriophage MS2 only encodes

4 gene products

What are the gene products of Bacteriophage MS2

C- coat protein
P- RNA directed RNA poly
L- Lysis protein
A- maturation protein

what does lysis protein do

allows virus to leave bacterial cell

Burst size of Bacteriophage MS2

20,000 PFU

What is the control mechanism for producing lysis

is protein limiting the translation through coat such that there is a pausing of that ribosome and a frameshift

where is lysis protein located

-embedded within the gene for coat and RNA polymerase
i-t is in a different frame

How many copies of capsid (coat) protein is required to make and actual capsid/ per genome

180 copies

how many copes of maturation protein is needed

1

how many copes of coat protein is needed

multiple

how many copes of replicase protein is needed

only a few

coat protein is made at

the highest concentration

As the coat protein is translated what does ribosome do

it disrupts secondary structures and another ribosome will detect start site and begin translation

Translation initiation begins within regions of

secondary structures

as coat protein is synthesized

it binds to RNA molecule and prevents further translation of polymerase

The production of the gene product is controlled through

a complex structure that is controlled through a complex secondary structure that is adopted by the MS2 genome

RNA folding regulates

concentration of the amount of each gene produced

Maturation protein is regulated by

secondary structures when RNA polymerase transcribes

when RNA polymerase transcribes maturation protein it makes

tRNA genome and then we have coupled Tc/TL

Premature synthesis of lysis protein would result in

the termination of virus replication and NOT allow the 20,000 infectious progeny to be produced

Replicase (RNA-dependent RNA polymerase) is positively regulated by

coat protein translation

Replicase (RNA-dependent RNA polymerase) is negatively regulated by

actual coat protein

translation of coat protein does what

opens the initiation codon

How is translation of the proteins required for attachment regulated

by secondary structures that the MS@ genome acquires post replication

what is the maturation protein made from

the nascent mRNA(genome)

how do the secondary structures regulate translation/ transcription

they prevent the protein from being translated any later

in order to replicate the genome of an RNA virus the virus genome must

Encode an RNA-dependent RNA polymerase since one is not provided by the host cell