Identification and characterization of a porcine parvovirus nonstructural polypeptide.
Sera from porcine parvovirus (PPV)-infected swine fetuses immunoprecipitated and 84- to 86-kilodalton polypeptide in addition to the A and B virion structural proteins. This polypeptide, designated NS-1, was present in PPV-infected cell lysates but not in purified virions. Partial proteolysis mapping revealed that NS-1 was not related to the A and B viral structural proteins. All three proteins in infected cells were phosphorylated at serine residues, and NS-1 also contained phosphothreonine. From pulse-labeling experiments with either 32Pi or [35S]methionine, NS-1 was found to first appear 5 to 7 h postinfection, whereas the viral structural polypeptides were first synthesized 9 to 11 h postinfection. Pulse-chase experiments revealed that NS-1 initially appeared as an 84-kilodalton protein and was subsequently structurally modified to forms of slower electrophoretic mobilities. The time of appearance of NS-1 after virus infection coincided with the initiation of viral DNA synthesis, suggesting that this polypeptide (and the modified forms thereof) may be involved in PPV replication.
D000818:Animals; D010321:Parvoviridae / Q000378:metabolism*; D010766:Phosphorylation; D013552:Swine / Q000382:microbiology; D013997:Time Factors; D014764:Viral Proteins / Q000302:isolation & purification*; D014771:Virion / Q000032:analysis
D014764:Viral Proteins