The MHC-encoded TAP1/LMP2 bidirectional promoter is down-regulated in highly oncogenic adenovirus type 12 transformed...

Cells transformed by human adenovirus 12 (Ad12) exhibit extremely low surface levels of MHC class I molecules and contain reduced levels of class I heavy chain mRNAs. We report that levels of MHC-encoded TAP1 and LMP2 mRNAs are also down-regulated in Ad12-transformed rat cells, and that transcription of rat TAP1 and LMP2 transcripts is directed from a 564 bp intergenic region which is significantly less active in Ad12-transformed cells compared to those transformed with Ad5. Our results suggest that, in common with MHC class I gene expression, TAP1 and LMP2 gene expression is reduced mainly at the level of transcription in Ad12-transformed cells.