Simian virus 40 and polyoma virus stimulate overall cellular RNA and protein synthesis.

Abstract

In lytic infection with simian virus 40 and polyoma virus of monkey and mouse cells in tissue culture, synthesis of the viral tumor (T) antigens (T antigens) is rapidly followed by a mitogenic response of the host cell. The latter begins with virus-induced stimulation of overall cellular RNA and protein synthesis, leading to a substantial increase in cytoplasmic and nuclear RNA and protein. Stimulation begins within 1 hr after onset of T-antigen synthesis and also occurs if virus-induced DNA synthesis is blocked by metabolic inhibitors. The broad spectrum of biological and molecular effects induced by simian virus 40 and polyoma virus is, at least phenotypically, reminiscent of the pleiotropic impact exerted on target cells by nonviral mitogens and by certain growth-promoting steroid and polypeptide hormones.Simian virus 40 (SV40) and polyoma virus induce a lytic infection in permissive cells and an abortive ("transforming") infection in nonpermissive cells. These infections exhibit considerable similarity (for details and references, see ref. 1). Expression of the early viral gene-i.e., synthesis of virus-specific early 19S mRNAs and of the tumor antigens (T antigens), is rapidly followed by a mitogenic reaction of the host cell. This reaction includes virus-induced stimulation of overall cellular RNA synthesis and an increase in total, mainly ribosomal RNA, activation of the cellular DNA-synthesizing apparatus and duplication of the host cell chromatin (S phase). In nonpermissive cells, virus-induced S phase is followed by prophase and mitosis but no viral DNA is replicated. In permissive cells, S phase is paralleled by replication of viral DNA as a nucleohistone and by production of progeny virus and is followed by cell death (lysis). The early events of infection, including the activation of the cellular DNA-synthesizing apparatus, also occur if virus-induced DNA synthesis is blocked by metabolic in-In this paper we report that, in lytic infection, SV40-and polyoma-induced stimulation of cellular RNA synthesis is paralleled by stimulation of cellular protein synthesis which also occurs in the presence of araC or FdUrd.MATERIALS AND METHODS Primary mouse kidney (2), secondary monkey kidney, and CV-1 (a monkey kidney cell line) cultures were grown in 10-cm-diameter plastic dishes in reinforced Eagle's medium ("culture medium") containing 10% fetal bovine serum (GIBCO) (3,4 To separate cells into cytoplasmic and nuclear fractions, cultures were incubated for 10 min at 40C in lysis buffer (300 mM sucrose/10 mM Tris-HCI, pH 7.4/5 mM NaCI/3 mM MgCl2/0.5% Nonidet P-40), 1 ml per dish. The cells were scraped from the plates and passed through a syringe (20-gauge needle) seven times, and the lysate was centrifuged at 3000 X g for 15 min at 40C.To extract proteins, unfractionated cultures were suspended, at 1.0 ml per dish, in 1% NaDodSO4/1 mM NaH2PO4, pH 8.5; nuclear pellets were suspended in 0.25 ml per dish. To cytoplasmic fractions (1 ml per dish) 50 ,ul of 20% (wt/vol) NaDodSO4 was added. The lysates were...

Simian virus 40 and polyoma virus induce synthesis of heat shock proteins in permissive cells.

“…In polyoma-infected mouse kidney cells, preferential labeling of the 92,000-and 72,000-Mr proteins was less pronounced. It should be noted that the labeling of total and individual proteins in virus-infected cultures varies with the time of infection (9). The labeling of total and individual proteins after thermal treatment was closely similar in monkey and mouse cells (Table 1), the stimulation of the 92,000-and 72,000-Mr proteins being in the same order of magnitude as in virus-infected cells.…”

“…Confluent primary mouse kidney cultures and confluent cultures of CV-1 (African green monkey) cells in 9-cm-diameter petri dishes were mock infected or infected with polyoma virus or SV40, respectively, and incubated at 37°C as described previously (9). For thermal treatment (heat shock), cultures were incubated at 43.5°C for 1 h before labeling at 37°C for 2 h with 100 iCi of [35S]methionine (500 to 1,000 Ci/mmol; The Radiochemical Centre, Amersham, United Kingdom) in 2 ml of methionine-free medium.…”

“…The lytic infection of mouse and monkey cell cultures with polyoma virus or simian virus 40 (SV40), respectively, induces an increased synthesis of the majority of cellular proteins (9). Among these, two strongly stimulated host proteins fall into the same size range as the proteins mentioned above (E. W. Khandjian, P. Arrigo, T. Rose, and J.-M. Matter, Experientia 36: 749,1980).…”

Simian virus 40 large tumor antigen: a "RNA binding protein"?

“…Confluent primary mouse kidney cultures and cultures of CV-1 (African green monkey) cells were infected with SV40 or mock infected under the conditions described (21,22). The cultures were labeled 21-25 hr after infection with 100 ,uCi of [3S]-methionine (500-1000 Ci/mmol; 1 Ci = 3.7 X 1010 becT.uerels) in 2 ml of methionine-free medium, or 100 ,uCi of [5-H]-or [2-14C]uridine (540 mCi/mmol and 50 mCi/mmol, respectively) in 2 ml of medium, or 100 ,uCi of 32p; (carrier free) in 2 ml of phosphate-free medium.…”

Binding sites for monoclonal antibodies and for mRNPs on SV40 large T‐antigen determined with a cleavage map

“…Large T-antigen is a multifunctional protein [4] that is essential for viral DNA replication [5], for establishment and maintenance of cell transformation, and for tumor formation in animals [I, 41. Large T-antigen is also required for the mitotic response of the host cell [6, 71 which comprises stimulated nucleoplasmic transcription [8], increased overall cellular RNA and protein synthesis [9], and duplication of host chromatin. Although large T-antigen is mainly a nuclear protein, about 10 % of large T-antigen molecules are present in the cytoplasm and copurify with host mRNPs [lo], suggesting a possible role in mRNA maturation [ll] or translation.…”