Transcriptional coactivator, CIITA, is an acetyltransferase that bypasses a promoter requirement for TAF(II)250.
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.
Raval
A
A
Experimental Immunology Branch, National Cancer Institute, Building 10, Room 4B-36, National Institutes of Health, Bethesda, MD 20892, USA.
Howcroft
T K
TK
Weissman
J D
JD
Kirshner
S
S
Zhu
X S
XS
Yokoyama
K
K
Ting
J
J
Singer
D S
DS
D000123:Acetyltransferases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D006367:HeLa Cells; D015395:Histocompatibility Antigens Class I / Q000235:genetics*; D000949:Histocompatibility Antigens Class II / Q000235:genetics*; D006801:Humans; D009687:Nuclear Proteins; D011401:Promoter Regions, Genetic / Q000502:physiology*; D017434:Protein Structure, Tertiary; D015534:Trans-Activators / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D015533:Transcriptional Activation / Q000502:physiology*
D004268:DNA-Binding Proteins; D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II; C083728:MHC class II transactivator protein; D009687:Nuclear Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D000123:Acetyltransferases; D019204:GTP-Binding Proteins