Biochemical Studies on Bovine Adenovirus Type 3. VI. Identification of Virus-Specific Early Proteins and Tumor Antigens

Abstract

ABSTRACT. At least 13 species of bovine adenovirus type 3 (BAV3)-specific early proteins were detected when two dimensional electrophoregrams of the BAV3-infected and mock-infected cells were compared. The molecular weights and isoelectric points ranged from 15,000 to 80,000 and from 5.35 to 6.85, respectively. Using an immunoprecipitation method, analyses of T antigens were carried out using three types of anti T sera. These antisera were prepared from tumor-bearing mice as induced by cells transformed with whole or specific fragments of BAV3 DNA containing transforming gene(s), and characterized as being BAV3-specific by immunofluorescent studies. Proteins of an apparent molecular weight of 15,000 (15 K) and 54,000 (54 K) were identified as common immunoprecipitates between these antisera and extracts of the cells lytically infected with BAV3. Each of these proteins was found among BAV3-specific early proteins. These results suggest that the 15 K and 54 K proteins are BAV3 tumor antigens. On the other hand, in the BAV3-transformd cells, a protein with an apparent molecular weight of 80 K, instead of 15 K or 54 K protein, was detected, using the same method. Such observations in human adenoviruses have not been reported. The BAV3 15 K protein seems to be suitable for the study of physicochemical properties and functions of T antigen since it can be obtained in large amounts.

Establishment of a bovine adenovirus type 3 (BAV3)-transformed hamster cell line and characterization of BAV3-tumor associated surface antigens.

“…In addition, BHKT73 cells were proved to contain BAV3 DNA and its EcoRI D-fragment. These cells also released a tumor angiogenesis factor (38) and expressed T antigen (28). The appearance of all the phenotypes of BHKT73 cells thus is believed to be due to transformation by BAV3.…”

“…This locus has been shown to contain genes related to T antigen (28). Clearly, all the genetic information of BAV3 required for the transformation and expression of BAV3-TASAs is located between the map units 3.6 and 11.9 on the BAV3 genome.…”