Expression of Early Viral Gene Products in Adenovirus Type 12-infected and -transformed cells

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Abstract
Early viral gene products expressed in adenovirus type 12 (Ad12)-infected [human oral carcinoma KB, embryo kidneys HEK] cells and in 2 Ad12-transformed hamster cell lines and Ad12-induced rat tumor cell lines were analyzed by cell-free translation of virus-specific RNA which was selected by hybridization to cloned restriction endonuclease fragments of virus DNA. Proteins synthesized in vitro were analyzed by 1- and 2-dimensional gel electrophoresis. RNA encoded by early region E1A directs the synthesis of at least 8 polypeptides with apparent MW 38K, 36K, 30K, 28K, 26K, 25K, 24K and 22K. All these proteins are related to each other. E1B-specific RNA directs the synthesis of 3 proteins: 59K, 19K and 17K. Early region E2a codes for a 61K polypeptide which probably represents the single-strand DNA-binding protein of Ad12. RNA complementary to region E3 directs the synthesis of a 16K protein and RNA transcribed from region E4 the synthesis of polypeptides with MW 20K, 18K and 11.5K. A 67K polypeptide was mapped into the region within 11-28 map units (E2b). The analysis of proteins directed by virus-specific RNA prepared from 2 Ad12-transformed hamster cell lines (T637, HA12/7) and 1 Ad12-induced rat tumor line (RBT 12/3) showed that early regions E1 and E4 are expressed in all 3 Ad12-transformed cell lines. RNA transcribed from early regions E2 and E3 were detected in lines T637 and RBT12/3. The virus RNA prepared from the Ad12-transformed cell lines directed synthesis of polypeptides with MW very similar to those of early virus proteins from infected cells. In all 3 Ad12-transformed cell lines mentioned above, RNA were found which directed the synthesis of additional polypeptides of early regions E1 (34K) and E4 (25K, 24K) not detected in infected cells. The DNA sequence at 11-28 map units (coding for the 67K protein) is not expressed in the Ad-12-transformed cells.

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