Holzman L B, Marks R M, Dixit V M
Department of Internal Medicine, University of Michigan Medical School, Ann Arbor 48109.
Mol Cell Biol. 1990 Nov;10(11):5830-8. doi: 10.1128/mcb.10.11.5830-5838.1990.
We have previously described the cloning of a group of novel cellular immediate-early response genes whose expression in human umbilical vein endothelial cells is induced by tumor necrosis factor alpha in the presence of cycloheximide. These genes are likely to participate in mediating the response of the vascular endothelium to proinflammatory cytokines. In this study, we further characterized one of these novel gene products named B61. Sequence analysis of cDNA clones encoding B61 revealed that its protein product has no significant homology to previously described proteins. Southern analysis suggested that B61 is an evolutionarily conserved single-copy gene. B61 is primarily a hydrophilic molecule but contains both a hydrophobic N-terminal and a hydrophobic C-terminal region. The N-terminal region is typical of a signal peptide, which is consistent with the secreted nature of the protein. The mature form of the predicted protein consists of 187 amino acid residues and has a molecular weight of 22,000. Immunoprecipitation of metabolically labeled human umbilical vein endothelial cell preparations revealed that B61 is a 25-kilodalton secreted protein which is markedly induced by tumor necrosis factor.
我们之前描述过一组新型细胞即刻早期反应基因的克隆，在放线菌酮存在的情况下，肿瘤坏死因子α可诱导这些基因在人脐静脉内皮细胞中表达。这些基因可能参与介导血管内皮对促炎细胞因子的反应。在本研究中，我们进一步对其中一个名为B61的新型基因产物进行了表征。对编码B61的cDNA克隆进行序列分析表明，其蛋白质产物与先前描述的蛋白质没有明显的同源性。Southern分析表明B61是一个进化上保守的单拷贝基因。B61主要是一种亲水分子，但包含一个疏水的N端和一个疏水的C端区域。N端区域是典型的信号肽，这与该蛋白质的分泌性质一致。预测蛋白质的成熟形式由187个氨基酸残基组成，分子量为22,000。对代谢标记的人脐静脉内皮细胞制剂进行免疫沉淀显示，B61是一种25千道尔顿的分泌蛋白，可被肿瘤坏死因子显著诱导。
