Nature and origin of the RNA associated with simian virus 40 large tumor antigen

Simian virus 40 (SV40) large tumor (T) antigen isolated from mammalian cells undergoing lytic or transforming infection is associated with small RNA fragments ("T-antigen RNA") that are protected from nuclease digestion. The rather high complexity of the ribonuclease T1 fingerprints of T-antigen RNA suggested that it is mainly derived from cellular heterogeneous nuclear RNAs. In the present study, 5'-32P-labeled T-antigen RNA was hybridized to monkey, mouse, and human Alu and SV40 DNA, and the nucleotide sequence of 37 T1 oligonucleotides was determined. The results suggest that the bulk of T-antigen RNA is derived from noncoding, double-stranded, ordered regions of cellular heterogeneous nuclear RNAs that exhibit sequence homologies with interspersed repetitive elements of the cellular genome. The possible biological implications of these results are discussed.