Antibody directed to a synthetic peptide encoding the NH2-terminal 16 amino acids of the adenovirus type 2 E1B-53K tumor antigen recognizes the E1B-20K tumor antigen.

Abstract A peptide, H 2 N-Glu-Arg-Arg-Asn-Pro-Ser-Glu-Arg-Gly-Val-Pro-Ala-Gly-Phe-SerGly-(Cys)COOH, containing the amino acid sequence at the NH 2 terminus of the adenovirus type 2 (Ad2) ElB-coded large T antigen (ElB-53K) has been synthesized. Anti-peptide antibody was generated in rabbits and used to immunoprecipitate Ad T antigens from Ad2 early infected cell extracts. In addition to the expected ElB-53K T antigen, anti-peptide antibody precipitated the Ad2 ElB-20K T antigen that was previously shown to be related to EIB-53K (M. Green, K. H. Brackmann, M. A. Cartas, and T. Matsuo, J. Virol. 42 , 30–41,1982). Anti-peptide antibody prepared against the COOH terminus of the E1B-53K T antigen or against the NH 2 terminus of the ElB-19K T antigen did not precipitate the EIB-20K T antigen. These data suggest that the Ad2 ElB-20K T antigen initiates translation at nucleotide 2016 in reading frame 3, as does ElB-53K. The viral mRNA that encodes the E1B-20K T antigen has not been identified.