Shutdown of Macromolecular Synthesis

Question 1

Influenza

Answer 1

RNA virus that needs capped RNA as primer to initiate synth

RNA POL II is removed 10-15 nucleotides from 5’ end by viral cap-dependent endonuclease (part of RNA POL)

‘cap stealing’

Question 2

Herpes

Answer 2

ORF57 redistributes spiceosomes and viral genes remain predominantly unspliced

HSV virion host shutoff (VHS) protein acts to reduce stability of mRNA in cytoplasm, causes initial decrease in amount of cellular mRNA

Question 3

Enteroviruses

Answer 3

encode protein that alters the ribosome so it no longer recognizes 5’ cap structures

virus utilizes IRES for initiation of translation and ribosomes act on virus mRNAs

Question 4

Polio

Answer 4

encodes protease which cleaves initiation factors eIF4GI/II and PABP

decreases translation of capped host mRNAs, allows translation of IRES containing virus mRNAs