Comparison of the DNA sequence of the Crawford small-plaque variant of polyomavirus with those of polyomaviruses A2 and strain 3

Abstract

The DNA sequence of two wild-type strains of polyomavirus (A2 and strain 3) are known. We have determined the majority of the DNA sequence of a third strain, the Crawford small-plaque virus. This virus has been noted for its capacity to induce readily detected tumor-specific transplantation antigen in hamster cells, a property that is most likely attributable to an altered middle T-antigen. A comparison of its DNA sequence with those of the A2 and strain 3 viruses reveals numerous nucleotide substitutions, insertions, and deletions throughout the genome. Most sequence changes in coding regions are silent mutations; however, variability in proteins can be predicted from these sequence data at 5 locations in middle T-antigen, 10 in large T-antigen, and 10 in VP1. The Crawford small-plaque virus noncoding regulatory region contains, in addition to nucleotide substitutions, a 44-base-pair tandem repeat of sequences on the late side of the origin of DNA replication.

A nonlethal mutation in large T antigen of polyomavirus which affects viral DNA synthesis

“…is present in wild-type A3 (28), was discovered near the HindlIl site in both the A2 and RA strains from our laboratory. tion of free viral DNA which is derived by replication from the integrated sequences (38).…”

Assembly of transfected DNA into chromatin: structural changes in the origin-promoter-enhancer region upon replication.

“…is associated with a DNase I-hypersensitive site (Herbomel et al, 1981, and in preparation). Duplication of this element generates a second DNase I-hypersensitive site (Rothwell and Folk, 1983). (iii) A DNase I-hypersensitive site is located within the enhancer element of the active immunoglobulin heavy chain cluster.…”

Recombination resulting in unusual features in the polyomavirus genome isolated from a murine tumor cell line

“…The primary structure of nucleotides derived from coding regions was identical to that reported for a small-plaque strain of polyomavirus (47), but the noncoding regulatory region could not be assigned to any particular strain. It retained features reminiscent of other strains, but its sequence was identical to none of those reported to date (11,21,47,50,57,64). Furthermore, substantial genomic reorganization appears to have occurred by recombination at the sites shown, a through f, to produce a series of tandem viral DNA elements, a reiteration of the viral B-element enhancer (26), and a double inversion (Fig.…”