Mouse p53 inhibits SV40 origin-dependent DNA replication

Abstract

p53 is a cellular phosphoprotein that is present at elevated concentrations in cells transformed by different agents. p53 complementary DNA expression-constructs immortalize primary cells in vitro and co-operate with an activated ras oncogene in malignant transformation. Several reports have implicated p53 in mammalian cell cycle control and specifically with events occurring at the G0-G1 boundary. p53 forms specific complexes with simian virus 40 (SV40) large-T antigen, and such complexes are found associated with both replicating and mature SV40 DNA in lytically infected cells. In an accompanying paper Gannon and Lane report that in in vitro plate-binding assays, mouse p53 can displace polymerase alpha from complex with T-antigen. We have examined the in vivo consequences of expressing wild-type and mutant p53 proteins from other species in SV40-transformed monkey cells. We report here that expression of mouse p53 results in a substantial and selective inhibition of SV40 origin-dependent DNA replication. In addition to any function in the G0-G1 transition, the data presented suggest that p53 may affect directly the initiation or maintenance of replicative DNA synthesis.

Correlation of DNA content, p53, T antigen, and V antigen in simian virus 40‐infected human diploid cells

“…A report by Gerard (9) indicated that mouse cells transformed with a BPV T antigen expression vector produced levels higher than Cos 1 cells, but failed to replicate exogenously added SV40 DNA. Recently, in vitro studies have examined the role of primate polymerase a-complex formation with SV40-T antigen in both permissive and nonpermissive cell lysates (2,43). Initially, polymerase a appeared to be the limiting factor in the lytic cycle.…”

“…Studies by Yewdell, Gannon and Lane indicate a competition by p53 and polymerase a for binding with SV40 T antigen (43). A report by Braithwaite et al (2) indicated that mouse p53 can displace the primate polymerase a, and they suggest that differences beween mouse and human p53 play a part in defining viral host range. Furthermore, this could be a means of control by SV40 T antigen for both viral DNA and host DNA replication.…”

Nuclear protein phosphorylation and growth control

“…The mechanism by which p53 regulates cell growth at the molecular level is still unknown. However, its ability to block SV40 DNA replication (Braithwaite et al, 1987;Wang et al, 1989;Sturtzbecher et al, 1988) and interact with proteins involved in DNA replication (Gannon & Lane, 1987;Wilcock & Lane, 1991) have suggested that it might normally regulate the initiation of cellular DNA replication. Other studies have shown that p53 is a potent transcriptional activator (Raycroft et al, 1990;Fields & Jang, 1990;O'Rourke etal., 1990).…”

A functional analysis of p53 during early development of xenopus laevis

“…There is also evidence that p53 plays a role in DNA replication. It was ®rst shown that p53 can bind to large T antigen, a DNA helicase directly involved in the initiation of SV40 DNA replication, and thereby inhibit its activity (Kress et al, 1979;Lane and Crawford, 1979;Braithwaite et al, 1987). Dutta et al (1993) also demonstrated that the interaction of p53 with the replication protein A (RPA), a single-strand DNA binding protein required for initiation of chromosomal replication, could contribute to the inhibition of cellular DNA replication in vitro.…”