Abstract
The adenovirus major late promoter functions at early and intermediate times to produce a limited set of mRNAs that appear in the cytoplasm of productively infected HeLa cells. These mRNAs may be translated in cell-free systems to produce two unrelated polypeptides of approximately 13,500 M r (L0-13.5K and L0-13.6K) and a pair of related polypeptides of approximately 55,000 M r (the L1-52K/55K proteins). Radiochemical protein sequence analysis of in vitro synthesized proteins has identified the N-terminal sequences of the L0-13.5K and L0-13.6K proteins (J. B. Lewis and C. W. Anderson 1983, Virology 127, 112–123). Additional sequence analyses confirmed the identification of the open reading frame for the L0-13.5K proteins and identified the ATG encoded by nucleotides 11,040 to 11,042 from the left end of the adenovirus genome as the initial codon of the L1-52K/55K protein. Antisera raised against synthetic peptides homologous to these three amino termini were used to demonstrate the presence of the L0-13.5K protein, the L0-13.6K protein, and the L1-52K/55K proteins in extracts of HeLa cells infected by adenovirus 2. The L0-13.5K protein was detected at early, intermediate, and late times after infection. The L0-13.6K and L1-52K/55K proteins were detected only at late times. Immunofluorescence microscopy indicated that the L0-13.6K protein is distributed around the periphery of the nucleus and along fibers running the length of the cell. Nonpermeabilized infected cells were stained by anti-L0-13.6K peptide serum at a single spot on the cell surface. Neither the L0-13.6K nor the L1-52K/55K proteins were detected in purified virus.
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