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Title: Genetic mapping of a major site of phosphorylation in adenovirus type 2 E1A proteins

Journal Article · · J. Virol.; (United States)
OSTI ID:6046403

Adenovirus early region 1A (E1A) encodes two acidic phosphoproteins which are required for transactivation of viral transcription, efficient viral DNA replication in phase G/sub 0/-arrested human cells, and oncogenic transformation of rodent cells. Biochemical analysis of in vivo /sup 32/P-labeled adenovirus type 2 E1A proteins purified with monoclonal antibodies demonstrated that these proteins were phosphorylated at multiple serine residues. Two-dimensional phosphotryptic peptide maps of wild-type and mutant E1A proteins were used to locate a major site of E1A protein phosphorylation at serine-219 of the large E1A protein. Although this serine fell within a consensus sequence for phosphorylation by the cyclic AMP-dependent protein kinases, experiments with mutant CHO cells defective in these enzymes indicated that it was not. Oligonucleotide-directed mutagenesis was used to substitute an alanine for serine-219. This mutation prevented phosphorylation at this site. Nonetheless, the mutant was indistinguishable from the wild type for early gene transactivation, replication on G/sub 0/-arrested WI-38 cells, and transformation of cloned rat embryo fibroblast cells.

Research Organization:
Univ. of California, Los Angeles (USA)
OSTI ID:
6046403
Journal Information:
J. Virol.; (United States), Vol. 59:1
Country of Publication:
United States
Language:
English