The nucleotide sequence of mRNA for the Mr 19 000 glycoprotein from early gene block III of adenovirus 2.

The cytoplasmic poly(A)RNA from early stages of infection of HeLa cells by adenovirus 2 (Ad2), was used to synthesize cDNA. The resulting cDNA segments were inserted at the PstI site of the plasmid pBR322 after dG/dC tailing. The clones containing sequences corresponding to early region III transcripts were identified by hybridization against the SmaI-C fragment (76.5 to 91.9 map units) of the Ad2 genome. The clone pE22 which contained a copy of the mRNA coding for the Mr 19 000 glycoprotein was characterized in detail. A comparison with the genomic sequences allowed the identification of the splice between the x and y leaders. The nucleotide sequences CCGGTG and CAGTTT were found at the donor and acceptor sites of the splice junction, respectively. The coding region consisted of a continuous stretch of 159 amino acids with a hydrophobic N-terminus and two possible glycosylation sites. The triplet ATG was encountered twice in phase 3 before the actual site of initiation of translation, which was in phase 2. The 3'-untranslated region was 500 nucleotides long and contained an open, translational reading frame for a Mr 11 000 protein, following a potential initiator ATG. The sequence ATTAAA was observed 17 bp before the poly(A) tail.