Department of Cancer Immunology & AIDS, Dana-Farber Cancer Institute, Harvard Medical School, Dana 1420A, Boston, MA 02215, United States.
Microbes Infect. 2012 Jun;14(6):477-84. doi: 10.1016/j.micinf.2011.12.007. Epub 2011 Dec 22.
Major histocompatibility complex (MHC) class I and class II are crucial for the function of the human adaptive immune system. An NLR protein, CIITA (MHC class II transactivator), is a master regulator of MHC class II gene expression as well as of some of the genes involved in MHC class II antigen presentation. It has recently been discovered that another member of the NLR protein family, NLRC5, transcriptionally activates MHC class I genes, and thus acts as "CITA" (MHC class I transactivator), a counterpart to CIITA. In addition to MHC class I genes, NLRC5 can induce the expression of β2M, TAP1 and LMP2, essential components of MHC class I antigen presentation. These findings indicate that NLRC5 and CIITA are transcriptional regulators that orchestrate the concerted expression of critical components in the MHC class I and MHC class II pathways, respectively.
主要组织相容性复合体 (MHC) Ⅰ类和Ⅱ类对于人类适应性免疫系统的功能至关重要。NLR 蛋白 CIITA（MHC Ⅱ类转录激活物）是 MHC Ⅱ类基因表达以及一些 MHC Ⅱ类抗原呈递相关基因的主要调节因子。最近发现，NLR 蛋白家族的另一个成员 NLRC5 可转录激活 MHC Ⅰ类基因，因此它是 CIITA（MHC Ⅰ类转录激活物）的对应物。除 MHC Ⅰ类基因外，NLRC5 还可以诱导β2M、TAP1 和 LMP2 的表达，这些是 MHC Ⅰ类抗原呈递的必需成分。这些发现表明 NLRC5 和 CIITA 是转录调节因子，分别协调 MHC Ⅰ类和 MHC Ⅱ类途径中关键成分的协同表达。
