Nucleotide sequence at polyoma VP1 mRNA splice sites.

Double-stranded DNA complementary to total cytoplasmic polyadenylated RNA isolated late in infection from polyoma virus-infected mouse 3T6 cells was cloned in Escherichia coli by using the large HindIII-BamHI fragment of pBR322 plasmid DNA. Polyoma-specific DNA inserts were detected by hybridization, and then nucleotide sequences were determined from two clones. The sequence of the (formula see text) with prototypical mammalian splice sites, and the dashed arrows indicate possible alternative splice sites leading to the same spliced product. A sequence of 897 nucleotides was spliced out of the primary transcript during the processing of the mature VP1 mRNA. Restriction enzyme mapping with four other independently isolated clones indicates that these are the major splicing signals for the VP1 message. The distal splice site is 48 nucleotides upstream from the initiator codon.