K-562 cells lack MHC class II expression due to an alternatively spliced CIITA transcript with a truncated coding region.
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.
Day
Noel E
NE
Department of Medical Genetics, Graduate School of Medicine, The University of Tennessee Medical Center, 1924 Alcoa Highway, Knoxville, TN 37920, USA.
Ugai
Hideyo
H
Yokoyama
Kazunari K
KK
Ichiki
Albert T
AT
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*
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