Activation of class II MHC genes requires both the X box region and the class II transactivator (CIITA).
CIITA, a gene that can complement a transcriptional mutation of the major histocompatibility complex (MHC) class II genes, was tested for its ability to function as a coactivator, CIITA cDNA clones isolated showed alternative RNA splicing, but only one splice site combination was able to restore class II MHC gene expression. DNA-mediated transfection experiments showed that CIITA directs its activity through the X box element; the presence of CIITA leads to the formation of a higher order complex at the X box region; and CIITA contains a potent activation domain. These findings support the hypothesis that CIITA directly interacts with the MHC class II-specific transcription factors and is required for expression.
Riley
J L
JL
Department of Microbiology and Immunology Emory University School of Medicine Atlanta, Georgia 30322, USA.
Westerheide
S D
SD
Price
J A
JA
Brown
J A
JA
Boss
J M
JM
D017398:Alternative Splicing; D001402:B-Lymphocytes / Q000502:physiology; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D005802:Genes, MHC Class II; D006681:HLA-D Antigens / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D015345:Oligonucleotide Probes / Q000737:chemistry; D012333:RNA, Messenger / Q000235:genetics; D012045:Regulatory Sequences, Nucleic Acid; D015534:Trans-Activators / Q000502:physiology*; D015533:Transcriptional Activation
D018076:DNA, Complementary; D006681:HLA-D Antigens; C083728:MHC class II transactivator protein; D009687:Nuclear Proteins; D015345:Oligonucleotide Probes; D012333:RNA, Messenger; D015534:Trans-Activators