1. Transcriptional coactivator, CIITA, is an acetyltransferase that bypasses a promoter requirement for TAF(II)250
- Author
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T. Kevin Howcroft, Jenny P.-Y. Ting, Xin Sheng Zhu, Aparna Raval, Dinah S. Singer, Susan Kirshner, Jocelyn D. Weissman, and Kazunari Yokoyama
- Subjects
Transcriptional Activation ,CD74 ,chemical and pharmacologic phenomena ,Biology ,MHC Class II Gene ,Transactivation ,Transcription (biology) ,Acetyltransferases ,GTP-Binding Proteins ,Coactivator ,MHC class I ,CIITA ,Animals ,Humans ,Promoter Regions, Genetic ,Molecular Biology ,Histocompatibility Antigens Class I ,Histocompatibility Antigens Class II ,Nuclear Proteins ,Cell Biology ,Cell biology ,Protein Structure, Tertiary ,DNA-Binding Proteins ,Gene Expression Regulation ,Acetyltransferase ,Cancer research ,biology.protein ,Trans-Activators ,HeLa Cells ,Transcription Factors - Abstract
The CIITA coactivator is essential for transcriptional activation of MHC class II genes and mediates enhanced MHC class I transcription. We now report that CIITA contains an intrinsic acetyltransferase (AT) activity that maps to a region within the N-terminal segment of CIITA, between amino acids 94 and 132. The AT activity is regulated by the C-terminal GTP-binding domain and is stimulated by GTP. CIITA-mediated transactivation depends on the AT activity. Further, we report that, although constitutive MHC class I transcription depends on TAF(II)250, CIITA activates the promoter in the absence of functional TAF(II)250.
- Published
- 2001