Species-specific elements in the large T-antigen J domain are required for cellular transformation and DNA replication by simian virus 40.
The J domain of simian virus 40 (SV40) large T antigen is required for efficient DNA replication and transformation. Despite previous reports demonstrating the promiscuity of J domains in heterologous systems, results presented here show the requirement for specific J-domain sequences in SV40 large-T-antigen-mediated activities. In particular, chimeric-T-antigen constructs in which the SV40 T-antigen J domain was replaced with that from the yeast Ydj1p or Escherichia coli DnaJ proteins failed to replicate in BSC40 cells and did not transform REF52 cells. However, T antigen containing the JC virus J domain was functional in these assays, although it was less efficient than the wild type. The inability of some large-T-antigen chimeras to promote DNA replication and elicit cellular transformation was not due to a failure to interact with hsc70, since a nonfunctional chimera, containing the DnaJ J domain, bound hsc70. However, this nonfunctional chimeric T antigen was reduced in its ability to stimulate hsc70 ATPase activity and unable to liberate E2F from p130, indicating that transcriptional activation of factors required for cell growth and DNA replication may be compromised. Our data suggest that the T-antigen J domain harbors species-specific elements required for viral activities in vivo.
Sullivan
C S
CS
Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.
Tremblay
J D
JD
Fewell
S W
SW
Lewis
J A
JA
Brodsky
J L
JL
Pipas
J M
JM
D000595:Amino Acid Sequence; D000818:Animals; D000957:Antigens, Viral, Tumor / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D002472:Cell Transformation, Viral; D004261:DNA Replication; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D029968:Escherichia coli Proteins; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D007577:JC Virus / Q000276:immunology; D008322:Mammals; D008969:Molecular Sequence Data; D010750:Phosphoproteins / Q000378:metabolism; D011506:Proteins; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D056465:Retinoblastoma-Binding Protein 1; D050717:Retinoblastoma-Like Protein p130; D029701:Saccharomyces cerevisiae Proteins; D013539:Simian virus 40 / Q000276:immunology* / Q000472:pathogenicity; D013045:Species Specificity; D050680:Transcription Factor DP1; D014157:Transcription Factors / Q000378:metabolism; D014779:Virus Replication
D000957:Antigens, Viral, Tumor; D001426:Bacterial Proteins; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C494635:DnaJ protein, E coli; D050684:E2F Transcription Factors; D029968:Escherichia coli Proteins; D005656:Fungal Proteins; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D010750:Phosphoproteins; D011506:Proteins; D011994:Recombinant Proteins; D056465:Retinoblastoma-Binding Protein 1; D050717:Retinoblastoma-Like Protein p130; D029701:Saccharomyces cerevisiae Proteins; D050680:Transcription Factor DP1; D014157:Transcription Factors; C070319:YDJ1 protein, S cerevisiae