Altered DNA binding and replication activities of JC virus T-antigen mutants.
Ten mutations were introduced into the JC virus (JCV) T antigen within a region corresponding to the SV40 T-antigen DNA binding domain (SV40 amino acids 131 to 220); nine of these increased homology between the two proteins in sequences critical for SV40 T antigen DNA binding. All mutant JCV T antigens bound to JCV and SV40 origins of DNA replication. Binding efficiency relative to the of wild-type JCV T antigen ranged from 83 to 301% for the JCV binding sites and from 44 to 240% for the SV40 binding sites. Nine mutant proteins promoted viral DNA replication in primary human fetal glial (PHFG) and CV-1 cells. In PHFG cells, promotion of DNA replication ranged from 26 to 220% relative to that of wild-type T antigen; in CV-1 cells it ranged from 14 to 522%. Coding sequences for five mutant proteins were transferred into the hybrid virus M1 (SV40) [M1(SV40) contains coding sequences from JCV and regulatory sequences from SV40]. Wild-type T antigen promoted replication weakly from the SV40 origin in these hybrid viruses in CV-1 cells (2% that from the JCV origin); replication driven by the mutant proteins ranged from 110 to 412% of that induced by the wild-type protein. Efficient specific DNA binding by a mutant T antigen was not a reliable indicator of that mutant protein's ability to promote DNA replication.
Tavis
J E
JE
Department of Molecular and Cell Biology, Pennsylvania State University, University Park 16802.
Frisque
R J
RJ
D000595:Amino Acid Sequence; D000818:Animals; D000957:Antigens, Viral, Tumor / Q000235:genetics* / Q000378:metabolism; D002461:Cell Line, Transformed; D006224:Cricetinae; D004261:DNA Replication; D004279:DNA, Viral / Q000737:chemistry / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D006801:Humans; D007577:JC Virus / Q000235:genetics* / Q000254:growth & development / Q000276:immunology; D007668:Kidney; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009457:Neuroglia; D012689:Sequence Homology, Nucleic Acid; D013539:Simian virus 40 / Q000235:genetics / Q000254:growth & development; D014779:Virus Replication
D000957:Antigens, Viral, Tumor; D004279:DNA, Viral; D004268:DNA-Binding Proteins