Analysis of mouse polyomavirus mutants with lesions in the minor capsid proteins.
Polyomavirus mutants E, Q and H, expressing non-myristylated VP2, were generated by replacing the N-terminal glycine residue with glutamic acid, glutamine or histidine, respectively. Viruses mutated in either VP2 or VP3 translation initiation codons were also prepared. All mutated genomes, when transfected into murine host cells, gave rise to viral particles. Infectivity of VP2- and VP3- viruses, as measured by the number of cells expressing viral antigens, was dramatically diminished, indicative of defects in the early stages of infection. In contrast, the absence of a myristyl moiety on VP2 did not substantially affect the early steps of virus infection. No differences in numbers of cells expressing early or late viral antigens were observed between wild-type (wt) and E or Q myr- viruses during the course of a life cycle. Furthermore, no delay in virus DNA replication was detected. However, when cells were left for longer in culture, the number of infected cells, measured by typical virus bursts, was much lower when mutant rather than wt genomes were used. In situ, cell fractionation studies revealed differences in the interaction of viral particles with host cell structures. The infectivity of mutants was affected not only by loss of the myristyl group on VP2, but also, and to a greater extent, by alterations of the N-terminal amino acid composition.
Department of Genetics and Microbiology, Charles University in Prague, Viničná 5, 128 44 Prague 2, Czech Republic1.
Petra
P
Mannová
Department of Genetics and Microbiology, Charles University in Prague, Viničná 5, 128 44 Prague 2, Czech Republic1.
David
D
Liebl
Department of Virology, Royal Postgraduate Medical School, Hammersmith Hospital, London W12 0NN, UK2.
Nina
N
Krauzewicz
Department of Genetics and Microbiology, Charles University in Prague, Viničná 5, 128 44 Prague 2, Czech Republic1.
Anna
A
Fejtová
Institute of Molecular Genetics, Czech Academy of Sciences, Flemingovo n. 2, 166 37 Prague 6, Czech Republic3.
Jitka
J
Štokrová
Department of Genetics and Microbiology, Charles University in Prague, Viničná 5, 128 44 Prague 2, Czech Republic1.
Zdena
Z
Palková
Department of Virology, Royal Postgraduate Medical School, Hammersmith Hospital, London W12 0NN, UK2.
Beverly E
BE
Griffin
Department of Genetics and Microbiology, Charles University in Prague, Viničná 5, 128 44 Prague 2, Czech Republic1.
Jitka
J
Forstová
D000818:Animals; D000956:Antigens, Viral / Q000096:biosynthesis; D002213:Capsid / Q000235:genetics*; D036022:Capsid Proteins; D002460:Cell Line; D018387:Codon, Initiator; D004261:DNA Replication; D004279:DNA, Viral / Q000096:biosynthesis; D005347:Fibroblasts / Q000821:virology; D051379:Mice; D009154:Mutation; D019814:Myristic Acid / Q000378:metabolism; D011120:Polyomavirus / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D014162:Transfection; D014779:Virus Replication
D000956:Antigens, Viral; D036022:Capsid Proteins; D018387:Codon, Initiator; D004279:DNA, Viral; C442543:VP2 protein, Polyomavirus; D019814:Myristic Acid