Enhancement of CIITA transcriptional function by ubiquitin.
Although increasing evidence indicates that there is a direct link between ubiquitination and mono-ubiquitination and transcription in yeast, this link has not been demonstrated in higher eukaryotes. Here we show that the major histocompatibility complex (MHC) class II transactivator (CIITA), which is required for expression of genes encoding MHC class II molecules, is ubiquitinated. This ubiquitination enhanced the association of CIITA with both MHC class II transcription factors and the MHC class II promoter, resulting in an increase in transactivation function and in the expression of MHC class II mRNA. The degree of CIITA ubiquitination was controlled by histone acetylases (HATs) and deacetylases (HDACs), indicating that the crucial cellular processes mediated by these enzymes are linked to regulate transcription. Thus, ubiquitin positively regulates a mammalian coactivator by enhancing its assembly at the promoter.
Greer
Susanna F
SF
Lineberger Comprehensive Cancer Center, and Department of Microbiology and Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
Zika
Eleni
E
Conti
Brian
B
Zhu
Xin-Sheng
XS
Ting
Jenny P-Y
JP
D000818:Animals; D002843:Chromatin / Q000378:metabolism; D000949:Histocompatibility Antigens Class II / Q000096:biosynthesis / Q000235:genetics; D006655:Histone Deacetylases / Q000378:metabolism; D006801:Humans; D009687:Nuclear Proteins; D011401:Promoter Regions, Genetic; D015534:Trans-Activators / Q000378:metabolism*; D015533:Transcriptional Activation; D025801:Ubiquitin / Q000378:metabolism*
D002843:Chromatin; D000949:Histocompatibility Antigens Class II; C083728:MHC class II transactivator protein; D009687:Nuclear Proteins; D015534:Trans-Activators; D025801:Ubiquitin; D006655:Histone Deacetylases