Activation of SV40 DNA replication in vitro by cellular protein phosphatase 2A.
AUTOR(ES)
Virshup, D M
RESUMO
We have made use of the cell-free SV40 DNA replication system to identify and characterize cellular proteins required for efficient DNA synthesis. One such protein, replication protein C (RP-C), was shown to be involved with SV40 large T antigen in the early stages of viral DNA replication in vitro. We demonstrate here that RP-C is identical to the catalytic subunit of cellular protein phosphatase 2A (PP2Ac). The purified protein dephosphorylates specific phosphoamino acid residues in T antigen, consistent with the hypothesis that SV40 DNA replication is regulated by modulating the phosphorylation state of the viral initiator protein. We also show that purified RP-C/PP2Ac preferentially stimulates SV40 DNA replication in extracts from early G1 phase cells. This finding suggests that the activity of a cellular factor that influences the net phosphorylation state of T antigen is cell cycle dependent.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=402079Documentos Relacionados
- Mechanism of activation of simian virus 40 DNA replication by protein phosphatase 2A.
- Cellular factors required for multiple stages of SV40 DNA replication in vitro.
- c-myc protein can be substituted for SV40 T antigen in SV40 DNA replication.
- Simian virus 40 (SV40) small t antigen inhibits SV40 DNA replication in vitro.
- Simian virus 40 (SV40) DNA replication: SV40 large T antigen unwinds DNA containing the SV40 origin of replication.
