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.
MeSH terms
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Acetyltransferases / genetics
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Acetyltransferases / metabolism*
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Animals
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism
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GTP-Binding Proteins / chemistry
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GTP-Binding Proteins / genetics
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GTP-Binding Proteins / metabolism
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Gene Expression Regulation
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HeLa Cells
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Histocompatibility Antigens Class I / genetics*
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Histocompatibility Antigens Class II / genetics*
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Humans
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Nuclear Proteins*
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Promoter Regions, Genetic / physiology*
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Protein Structure, Tertiary
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Trans-Activators / chemistry
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Trans-Activators / genetics*
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Trans-Activators / metabolism*
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Transcription Factors / genetics
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Transcription Factors / metabolism
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Transcriptional Activation / physiology*
Substances
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DNA-Binding Proteins
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Histocompatibility Antigens Class I
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Histocompatibility Antigens Class II
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MHC class II transactivator protein
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Nuclear Proteins
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Trans-Activators
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Transcription Factors
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Acetyltransferases
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GTP-Binding Proteins