Characterization of the mouse lymphotoxin-beta gene.
Characterization of the mouse lymphotoxin-beta gene.
复制标题
小鼠淋巴毒素-β 基因的表征。
作者：
P. Lawton;J. Nelson;R. Tizard;J. Browning
淋巴毒素-β（LT-β）是TNF配体家族的成员，当与淋巴毒素-α（LT-α，即，原始LT或TNF-β）与细胞表面上的LT-α形成异聚复合物。小鼠的基因结构，确定了cDNA克隆和分析的基因组DNA片段，包括TNF/LT基因座的H-2区的17号染色体。小鼠和人类的基因组结构被发现在MHC的III类区域的位置方面是相似的;然而，小鼠基因缺少一个在该家族的大多数成员中发现的内含子。cDNA和基因组序列均显示在常规内含子2位置的剪接供体改变，使其无功能。改变的基因保留开放的阅读框，使得额外的66个氨基酸被插入到连接跨膜结构域与该II型膜蛋白中外显子4编码的受体结合结构域的茎区中。北方分析表明该基因主要在淋巴器官中表达。小鼠肿瘤坏死因子基因座的克隆将为进一步研究这些基因与免疫功能之间的关系奠定基础。
Lymphotoxin-beta (LT-beta) is a member of the TNF family of ligands which when expressed with lymphotoxin-alpha (LT-alpha, i.e., the original LT or TNF-beta) forms a heteromeric complex with LT-alpha on the cell surface. The mouse gene structure was determined by both cDNA cloning and analysis of a genomic DNA fragment encompassing the TNF/LT locus in the H-2 region of chromosome 17. The mouse and human genomic structures were found to be similar in terms of location in the class III region of the MHC; however, the mouse gene lacks one intron found in most members of the family. Both the cDNA and the genomic sequences revealed an altered splice donor in the conventional intron 2 position, rendering it nonfunctional. The altered gene retains an open reading frame such that an additional 66 amino acids are inserted into the stalk region connecting the transmembrane domain with the receptor binding domain encoded by exon 4 in this type II membrane protein. Northern analysis showed that this gene is expressed predominantly in lymphoid organs. The outlining of the complete mouse TNF locus will further studies of the relationship between these genes and immune function.