title: K-562 cells lack MHC class II expression due to an alternatively spliced CIITA transcript with a truncated coding region.
abstract: The focus of this study was to determine the functional capacity of class II transactivator (CIITA), a regulatory factor of major histocompatibility complex (MHC) class II genes, in K-562 cells. We show that CIITA mRNA is present in K-562 cells and the interferon-gamma (IFN-gamma)-inducible CIITA promoter-IV exhibits low levels of basal activity, which is greatly enhanced upon treatment with IFN-gamma. Further study revealed that the CIITA cDNA contains an insertion of genomic sequence, which introduces a stop codon. The truncated coding region of the CIITA transcript in K-562 cells provides a possible explanation for the absence of MHC class II molecules.
authors.affiliation: Department of Medical Genetics, Graduate School of Medicine, The University of Tennessee Medical Center, 1924 Alcoa Highway, Knoxville, TN 37920, USA.
authors.forename: Noel E
authors.initials: NE
authors.lastname: Day
authors.forename: Hideyo
authors.initials: H
authors.lastname: Ugai
authors.forename: Kazunari K
authors.initials: KK
authors.lastname: Yokoyama
authors.forename: Albert T
authors.initials: AT
authors.lastname: Ichiki
mesh_terms: D017398:Alternative Splicing; D000595:Amino Acid Sequence; D018388:Codon, Terminator; D004251:DNA Transposable Elements; D005802:Genes, MHC Class II; D000949:Histocompatibility Antigens Class II / Q000378:metabolism; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology; D020014:K562 Cells / Q000378:metabolism*; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics*
chemical_list: D018388:Codon, Terminator; D004251:DNA Transposable Elements; D000949:Histocompatibility Antigens Class II; C083728:MHC class II transactivator protein; D009687:Nuclear Proteins; D012333:RNA, Messenger; D015534:Trans-Activators; D007371:Interferon-gamma