Mini-review: Specificity and expression of CIITA, the master regulator of MHC class II genes.
The class II transactivator (CIITA) has been referred to as the "master control factor" for the expression of MHC class II (MHCII) genes. As our knowledge on the specificity and function of CIITA grows, it is becoming increasingly evident that this sobriquet is entirely justified. First, despite extensive investigations, the major target genes of CIITA remain those implicated in the presentation of antigenic peptides by MHCII molecules. Although other putative target genes have been reported, the contribution of CIITA to their expression remains indirect, controversial or comparatively minor relative to its decisive role as a regulator of MHCII and related genes. Second, the most important parameter dictating MHCII expression is by far the expression pattern of the gene encoding CIITA (MHC2TA). The vast majority of signals that activate or repress MHCII expression under physiological and pathological situations converge on one or more of the three alternative promoters that drive transcription of the MHC2TA gene. In short, with respect to its specificity and its exquisitely controlled pattern of expression, CIITA is by a long stretch the single most important transcription factor for the regulation of genes required for MHCII-restricted antigen-presentation.
LeibundGut-Landmann
Salomé
S
Department of Pathology, University of Geneva Medical School, Geneva, Switzerland.
Waldburger
Jean-Marc
JM
Krawczyk
Michal
M
Otten
Luc A
LA
Suter
Tobias
T
Fontana
Adriano
A
Acha-Orbea
Hans
H
Reith
Walter
W
D000818:Animals; D017951:Antigen Presentation / Q000276:immunology; D005786:Gene Expression Regulation / Q000276:immunology*; D005802:Genes, MHC Class II / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000235:genetics*; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D015534:Trans-Activators / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D014157:Transcription Factors / Q000276:immunology; D015533:Transcriptional Activation / Q000276:immunology
D000949:Histocompatibility Antigens Class II; C083728:MHC class II transactivator protein; D009687:Nuclear Proteins; D015534:Trans-Activators; D014157:Transcription Factors