Expression of MHC class II molecules in different cellular and functional compartments is controlled by differential usage of multiple promoters of the transactivator CIITA. |
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Authors: | A Muhlethaler-Mottet L A Otten V Steimle B Mach |
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Affiliation: | Department of Genetics and Microbiology, University of Geneva Medical School, Switzerland. |
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Abstract: | The highly complex pattern of expression of major histocompatibility complex class II (MHC-II) molecules determines both the immune repertoire during development and subsequently the triggering and the control of immune responses. These distinct functions result from cell type-restricted expression, developmental control and either constitutive or inducible expression of MHC-II genes. Yet, in these various situations, MHC-II gene expression is always under the control of a unique transactivator, CIITA. Here we show that the CIITA gene is controlled by several distinct promoters, two of which direct specific constitutive expression in dendritic cells and B lymphocytes respectively, while another mediates gamma-interferon-induced expression. Thus the cellular, temporal and functional diversity of MHC-II expression is ultimately controlled by differential activation of different promoters of a single transactivator gene. This provides novel experimental tools to dissect compartment-specific gain or loss of MHC-II function in vivo. |
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