Recently, a non-DNA binding protein, class II transactivator (CIITA), has been shown to be required for constitutive and IFN-gamma-inducible class II MHC transcription. The cytokine TGF-beta inhibits IFN-gamma-induced class II MHC expression at the transcriptional level. In this study, we provide evidence that TGF-beta blocks IFN-gamma-induced CIITA mRNA accumulation. TGF-beta down-regulates class II MHC and CIITA mRNA accumulation in human astroglioma and fibrosarcoma cell lines, but TGF-beta does not destabilize the CIITA message, suggesting an effect at the transcriptional level. In cells that stably overexpressed CIITA, leading to a constitutive class II MHC-positive phenotype, the inhibitory effect of TGF-beta on class II MHC was abrogated, but the cells remained responsive for expression of TGF-beta-inducible genes. Cell lines that possessed defects in TGF-beta signaling also became refractory to inhibition of IFN-gamma-induced CIITA and class II MHC expression. Our data indicate that TGF-beta suppresses IFN-gamma-induced class II MHC expression by inhibiting accumulation of CIITA mRNA.
TGF-beta suppresses IFN-gamma induction of class II MHC gene expression by inhibiting class II transactivator messenger RNA expression.
Yi-Ju Lee,Yulong Han,Hong Tao Lu,V. Nguyen,H. Qin,P. Howe,B. A. Hocevar,J. Boss,R. Ransohoff,E. Benveniste
Published 1997 in Journal of Immunology
ABSTRACT
PUBLICATION RECORD
- Publication year
1997
- Venue
Journal of Immunology
- Publication date
1997-03-01
- Fields of study
Biology, Medicine, Chemistry
- Identifiers
- External record
- Source metadata
Semantic Scholar, PubMed
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