TRAC - T cell receptor alpha constant Gene

中文名称：细胞受体α常数

种属: Homo sapiens

同用名: TRA; IMD7; TCRA; TRCA

关于 TRAC

功能概要

细胞受体识别已被加工成小肽并与抗原呈递细胞 (APC) 表面的主要组织相容性复合体 (MHC) 分子结合的外来抗原。每个 T 细胞受体都是一个二聚体，由一条α链和一条β链或一条δ链和一条γ链组成。在单个细胞中，T 细胞受体基因座以 delta、gamma、beta 和 alpha 的顺序重新排列和表达。如果 delta 和 gamma 重排都产生功能链，则细胞表达 delta 和 gamma。如果不是，细胞会继续重新排列 beta 和 alpha 位点。该区域代表 T 细胞受体 alpha 和 delta 基因座的种系组织。 alpha 和 delta 基因座都包括 V (可变) 、J (连接) 和 C (恒定) 片段，delta 基因座还包括多样性 (D) 片段。 delta 基因座位于 alpha 基因座内，介于 alpha V 和 J 区段之间。在 T 细胞发育过程中，δ 链是通过 DNA 水平的重组事件合成的，将 D 片段与 J 片段连接起来；然后将 V 片段连接到 DJ 基因。 α 链是通过重组连接单个 V 区段和 J 区段而合成的。对于这两条链，C 区段随后通过 RNA 水平的剪接连接起来。许多不同的 V 区段与几个 J 区段的重组提供了广泛的抗原识别。额外的多样性是通过连接多样性获得的，连接多样性是由末端脱氧核苷酸转移酶随机添加核苷酸引起的。五个可变区段可用于 alpha 或 delta 链，并由 TRAV/DV 符号描述。已知 alpha 基因座的几个 V 和 J 片段不能编码蛋白质，因此被认为是假基因。[RefSeq 提供，2016 年 8 月]

T cell receptors recognize foreign antigens which have been processed as small peptides and bound to major histocompatibility complex (MHC) molecules at the surface of antigen presenting cells (APC). Each T cell receptor is a dimer consisting of one alpha and one beta chain or one delta and one gamma chain. In a single cell, the T cell receptor loci are rearranged and expressed in the order delta, gamma, beta, and alpha. If both delta and gamma rearrangements produce functional chains, the cell expresses delta and gamma. If not, the cell proceeds to rearrange the beta and alpha loci. This region represents the germline organization of the T cell receptor alpha and delta loci. Both the alpha and delta loci include V (variable), J (joining), and C (constant) segments and the delta locus also includes diversity (D) segments. The delta locus is situated within the alpha locus, between the alpha V and J segments. During T cell development, the delta chain is synthesized by a recombination event at the DNA level joining a D segment with a J segment; a V segment is then joined to the D-J gene. The alpha chain is synthesized by recombination joining a single V segment with a J segment. For both chains, the C segment is later joined by splicing at the RNA level. Recombination of many different V segments with several J segments provides a wide range of antigen recognition. Additional diversity is attained by junctional diversity, resulting from the random additional of nucleotides by terminal deoxynucleotidyltransferase. Five variable segments can be used in either alpha or delta chains and are described by TRAV/DV symbols. Several V and J segments of the alpha locus are known to be incapable of encoding a protein and are considered pseudogenes. [provided by RefSeq, Aug 2016]