SV40-specific RNA in the nucleus and polyribosomes of transformed cells.

Cells transformed by the oncogenic virus SV40 are known to contain viral DNA integrated into cellular DNA and to produce virus-specific RNA. It has been shown that nuclear molecules containing virus-specific sequences are considerably longer than presumed virus-specific mRNA molecules from cytoplasmic polyribosomes. This finding suggests the possibility that cytoplasmic mRNA is derived by the specific cleavage of larger nuclear RNA.