Two colinear and spliced viral transcripts are present in non-virus-producing benign and malignant neoplasms induced by the shope (rabbit) papilloma virus

Abstract

The nature of Shope virus-specific RNA was investigated in non-virus-producing Shope (rabbit) papilloma virus-induced benign and malignant domestic rabbit tumors and in a cell line derived from the VX-7 transplantable carcinoma. RNA transfer (Northern) blot analysis of polyadenylated RNA isolated from whole cell extracts of all three sources was resolved into two major bands of 1.3 and 2.0 kilobases. Two additional minor bands of 3.5 and 4.8 kilobases could be seen in some analyses. RNA of the VX-7 cell line was further separated into nuclear, cytoplasmic, and polysomal fractions. The cytoplasmic fraction only contained the 1.3- and 2.0-kilobase species, and virus-specific RNA was found to be associated with polysomes. The two major transcripts present in VX-7 cells were mapped by hybridization of RNA transfer blots with subgenomic probes, and the results indicated that both transcripts are spliced and are most likely colinear. Our results are consistent with the suggestion that the two viral transcripts are necessary for induction and maintenance of the neoplasms.