Prolonged MHC class II expression and CIITA transcription in human keratinocytes.
A transcriptional cofactor, the MHC class II transactivator (CIITA), is a master regulator of MHC class II gene expression. CIITA expression is restricted in MHC class II-positive cells and is regulated by 4 (human) or 3 (mouse) promoters. To clarify the usage of human CIITA promoters in keratinocytes, we analyzed CIITA mRNA levels in IFN-gamma-stimulated normal human keratinocytes (NHK) by real-time PCR using promoter-specific primers. When the amount of total CIITA mRNA in NHK was quantified at 6h after IFN-gamma-stimulation, the amount of CIITA mRNA detected in NHK did not differ from that seen in the B cell line Raji or the IFN-gamma-stimulated macrophage cell line THP-1. Quantitative real-time PCR using promoter-specific primers showed that type IV CIITA mRNA was strongly transcribed and that type III CIITA mRNA was weakly transcribed in stimulated NHK, while no transcripts from pI and pII were detected. Although type IV mRNA in THP-1 was transiently transcribed by IFN-gamma-stimulation, transcription of type IV in IFN-gamma-stimulated keratinocytes was prolonged. This difference subsequently caused significantly higher expression at 72 h of MHC class II on NHK, compared with THP-1. This is the first report to quantitatively analyze each type of CIITA transcript in NHK.
Takagi
Atsushi
A
Department of Dermatology, Juntendo University School of Medicine, 2-1-1 Hongo, Tokyo 113-8421, Japan.
Nishiyama
Chiharu
C
Kanada
Shunsuke
S
Niwa
Yusuke
Y
Fukuyama
Kanako
K
Ikeda
Shigaku
S
Okumura
Ko
K
Ogawa
Hideoki
H
D002460:Cell Line; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D005434:Flow Cytometry; D006684:HLA-DR Antigens / Q000096:biosynthesis*; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology; D015603:Keratinocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D009687:Nuclear Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015534:Trans-Activators / Q000235:genetics*; D014158:Transcription, Genetic / Q000187:drug effects / Q000235:genetics
D006684:HLA-DR Antigens; C083728:MHC class II transactivator protein; D009687:Nuclear Proteins; D012333:RNA, Messenger; D015534:Trans-Activators; D007371:Interferon-gamma