22 SV40 and Polyomavirus DNA Replication

Abstract

The papovavirus family comprises two virus subgroups: the polyomaviruses and the papillomaviruses. The polyomavirus subgroup consists of a dozen members and includes simian virus 40 (SV40), the murine polyomavirus (PyV), and two human isolates, JCV and BKV (for review, see Tooze 1980). The polyomaviruses display strict species specificity for their replication, but otherwise share a common architecture, genome organization, and replication cycle. SV40 replicates in simian cells and to a lesser extent in human cells, whereas PyV replicates in cells of murine origin. The circular double-stranded DNA genomes of SV40 and PyV comprise about 5300 bp. The viral DNA is assembled into chromatin both in virions and in infected cells, and apart from the absence of histone H1, it is structurally indistinguishable from that of the cell.

This review focuses principally on the replication of SV40 DNA and draws on the PyV literature to highlight differences between these two papovaviruses where appropriate. Several excellent reviews on this subject have appeared recently (DePamphilis and Bradley 1986; Challberg and Kelly 1989; Stillman 1989; Hurwitz et al. 1990; Melendy and Stillman 1992). We refer the reader to these and to other chapters in this volume for more in-depth discussion of topics we are unable to describe here and for more comprehensive citations to the primary literature.

Since their discovery in the late 1950s, SV40 and PyV have served as paradigms to understand cellular processes as diverse as DNA replication, transcription, and oncogenic transformation. The rationale for employing these viruses as models for DNA...