title: Suppression of MHC class I RNA in highly oncogenic cells occurs at the level of transcription initiation.
abstract: The oncogenic potential of some transformed cell lines has been shown in animal tumor models to be the direct result of MHC class I mRNA suppression. Rodent cells established with the highly oncogenic human adenovirus type 12 exhibit greatly reduced levels of class I Ag compared with cells derived with the nononcogenic adenovirus type 5. By using seven independently derived adenovirus-transformed cell lines, we have investigated the mechanism responsible for down-regulation of class I RNA expression. In all adenovirus 12-transformed cells examined, class I RNA suppression was the result of a block in transcription initiation. Highly oncogenic cell lines derived from a spontaneous melanoma and a chemically induced sarcoma also showed greatly reduced transcription of class I genes. We conclude that suppression of MHC class I RNA in a variety of highly oncogenic cells results largely from a substantial decrease in transcription initiation.
authors.affiliation: Laboratory of Virology, Jerome H. Holland Laboratory, American Red Cross, Rockville, MD 20855.
authors.forename: N
authors.initials: N
authors.lastname: Lassam
authors.forename: G
authors.initials: G
authors.lastname: Jay
mesh_terms: D000260:Adenoviruses, Human / Q000502:physiology; D000818:Animals; D002461:Cell Line, Transformed; D015536:Down-Regulation; D015972:Gene Expression Regulation, Neoplastic; D005805:Genes, MHC Class I; D006801:Humans; D051379:Mice; D012334:RNA, Neoplasm / Q000096:biosynthesis*; D012513:Sarcoma, Experimental / Q000235:genetics; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured / Q000378:metabolism*; D001613:beta 2-Microglobulin / Q000235:genetics
chemical_list: D012334:RNA, Neoplasm; D001613:beta 2-Microglobulin