Adenovirus type 12 E1A gene represses accumulation of MHC class I mRNAs at the level of transcription.

The levels of the class I antigens and mRNAs of the major histocompatibility complex (MHC) are greatly diminished in cells transformed by adenovirus type 12 (Ad12). Although the Ad12-transforming gene, E1A, is responsible for reduced class I expression, the site at which E1A blocks accumulation of class I transcripts is not known. In this study, we demonstrate by nuclear run-on assays that in Ad12-transformed mouse cells, E1A acts by reducing the rate of transcription of class I genes.