Padilla Olga, Pujana Miguel Angel, López-de la Iglesia Agustí, Gimferrer Idoia, Arman Mònica, Vilà Josep Maria, Places Lourdes, Vives Jordi, Estivill Xavier, Lozano Francisco
Institut Clínic d'Infeccions i Immunologia (ICII), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic, Villarroel 170, 08036 Barcelona, Spain.
Immunogenetics. 2002 Dec;54(9):621-34. doi: 10.1007/s00251-002-0507-z. Epub 2002 Nov 6.
The scavenger receptor cysteine-rich superfamily (SRCR-SF) is a highly conserved group of membrane and/or secreted proteins related to the innate and adaptive immune system. Here, we report the cloning of the gene encoding human S4D-SRCRB, a novel soluble member of the SRCR-SF, which is composed of four group B SRCR domains separated by Pro-, Ser- and Thr-rich polypeptides. The longest cDNA sequence found is 2,806 bp in length and encodes a mature protein of 528 aa, with a predicted molecular mass of M(r) 55,600. The S4D-SRCRB gene is located at Chromosome 7q11.23, telomeric to the Williams-Beuren syndrome deletion. It extends over 20 kb and consists of 11 exons, with each SRCR domain being encoded by a single exon. Northern blot analysis indicated that S4D-SRCRB has a broad tissue distribution and is expressed as two major mRNA species: one of 2.8 kb, with a restricted tissue expression pattern (mainly kidney and placenta), and another of 1.5 kb, with a broader distribution. A similar mRNA expression pattern was observed during the analysis of several tumor cell lines. The highest degree of similarity found between S4D-SRCRB and other group B SRCR-SF members was with human DMBT1 (a mosaic protein composed of fourteen SRCR domains, which is involved in innate defense and epithelia polarization) and chicken 18-B (a turpentine-induced soluble acute-phase protein composed of four SRCR domains). Our data indicate that S4D-SRCRB constitutes a novel SRCR-SF member, which could be involved in basic homeostatic functions such as innate host defense.
富含半胱氨酸的清道夫受体超家族（SRCR-SF）是一组与先天性和适应性免疫系统相关的高度保守的膜蛋白和/或分泌蛋白。在此，我们报道了人类S4D-SRCRB编码基因的克隆，S4D-SRCRB是SRCR-SF的一个新型可溶性成员，它由四个B组SRCR结构域组成，这些结构域被富含脯氨酸、丝氨酸和苏氨酸的多肽分隔开。发现的最长cDNA序列长度为2806 bp，编码一个528个氨基酸的成熟蛋白，预测分子量为M(r) 55,600。S4D-SRCRB基因位于7号染色体q11.23，在威廉姆斯-贝伦综合征缺失区域的端粒位置。它延伸超过20 kb，由11个外显子组成，每个SRCR结构域由单个外显子编码。Northern印迹分析表明，S4D-SRCRB具有广泛的组织分布，并以两种主要的mRNA形式表达：一种为2.8 kb，具有受限的组织表达模式（主要在肾脏和胎盘中），另一种为1.5 kb，分布更广泛。在分析几种肿瘤细胞系时也观察到了类似的mRNA表达模式。S4D-SRCRB与其他B组SRCR-SF成员之间发现的最高相似度是与人类DMBT1（一种由14个SRCR结构域组成的镶嵌蛋白，参与先天性防御和上皮细胞极化）以及鸡18-B（一种由4个SRCR结构域组成的松节油诱导的可溶性急性期蛋白）。我们的数据表明，S4D-SRCRB构成了一个新型的SRCR-SF成员，可能参与诸如先天性宿主防御等基本的稳态功能。
