Identification of cellular targets of the adenovirus E1B 55-kDa protein
The adenovirus (Ad) E1B 55-kDa protein is vital to viral growth and complete transformation of adenovirus-infected cells. The detailed mechanisms of E1B action are not yet clear. In order to shed light on the functions of this viral oncoprotein it is essential to determine its cellular targets. The yeast two-hybrid method was utilized to screen the Saccharomyces cerevisiae genomic library and the human Hela cDNA library with the Ad2 E1B 55-kDa protein as bait. Partial screening of the S. cerevisiae genomic library (10[superscript 6] transformants) has revealed several yeast proteins that bind to E1B. Among these are : UFD1, involved in the ubiquitin fusion degradation pathway, a major pathway for selective protein degradation in eukaryotes, RIS1, a member of the SWI/SNF2 family of DNA-dependent ATPases, and Bdf2 which contains two copies of the evolutionarily conserved bromodomain, homologous to the C-terminal half of mammalian TAF[subscript ll]250. Human proteins positive for Ad2 E1B 55-kDa binding were identified through partial screening of the Hela eDNA library (7 × 10[superscript 5] transformants). The identification of a DAXX/Ad E1B 55-kDa interaction has interesting implications for the role of E1B in cell transformation."--Résumé abrégé par UMI.