The adenovirus early proteins.

Abstract

The adenovirus early proteins are defined as those proteins encoded by the virus that are synthesized prior to and in the absence of viral DNA replication. The functions of these early viral proteins provide new insights into the mechanisms of gene regulation and DNA replication in higher eukaryotic cells. These adenovirus proteins regulate transcription in both a positive (Berk et al. 1979; Jones and Shenk 1979; Ross et al. 1980 a) and a negative (Nevins and Winkler 1980) fashion, as well as affecting the stability of viral mRNA (Babich and Nevins 1981). Some early proteins may be involved in RNA processing (Klessig and Grodzicker 1979; Sarnow et al. 1982 a) or RNA transport out of the nucleus. Other early proteins are required for viral DNA replication (Van der Vliet et al. 1975; Challberg et al. 1980; Stillman et al. 1981; Lichyet al. 1981), specifying three distinct functions in this process. A subset of the early viral proteins are both necessary and sufficient for cellular transformation by this virus (Sambrook et al. 1975; Graham et al. 1974, 1975, 1978; Shenk et al. 1979). Other early gene products can affect the frequency of transformation by adenovirus (Ginsberg et al. 1974; Williams et al. 1974; Logan et al. 1981). Finally, the host range of human adenoviruses can be extended by mutations in some early viral genes (Klessig and Grodzicker 1979), implying that the life cycle of the virus and its tissue pathology and disease patterns may vary with early gene function or alterations in such functions.