The nucleotide sequence of mRNA for the Mr 19000 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 M_r 19000 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 M_r 11 000 protein, following a potential initiator ATG. The sequence ATTAAA was observed 17 bp before the poly(A) tail.