Furutani Y, Kato A, Yasue H, Alexander L J, Beattie C W, Hirose S
Department of Biological Sciences, Tokyo Institute of Technology,, Midoriku, Yokohama, 226-8501, Japan.
J Biochem. 1998 Sep;124(3):491-502. doi: 10.1093/oxfordjournals.jbchem.a022140.
Trappins are a group of secretory proteins containing a WAP motif with an anchoring domain. Previous studies showed that their genes, especially those of pig, have undergone rapid evolution, which produced trappins with a broad spectrum of actions. To understand the evolution of such a rapidly evolving multigene family, we isolated trappin genes of the Artiodactyla, including pig, wart hog, collared peccary, hippopotamus, and cow, by means of polymerase chain reaction (PCR). Two genes newly isolated from wart hog are orthologs of trappin-1 (SPAI) and trappin-2 (elafin), the others are novel members of the trappin family and named trappins-6 to 11. The divergence of the sequences is greatest in the region that encodes the reactive site, and intron sequences appear to be more highly conserved than the protein-coding sequences, especially among the pig paralogs. Phylogenetic analysis showed that the trappin multigene family members of pig were generated through gene duplication after the divergence of the Suidae (pig and wart hog) and Tayassuidae (collared peccary). Similarities in the gene structure with seminal vesicle clotting proteins (REST) and WAP motif-containing proteins suggest that trappins are naturally occurring fusion proteins created through exon shuffling between ancestral REST and WAP motif-coding genes.
捕集蛋白是一组含有WAP基序和锚定结构域的分泌蛋白。先前的研究表明，它们的基因，尤其是猪的基因，经历了快速进化，产生了具有广泛作用谱的捕集蛋白。为了了解这样一个快速进化的多基因家族的进化情况，我们通过聚合酶链反应（PCR）分离了偶蹄目动物的捕集蛋白基因，包括猪、疣猪、领西貒、河马和牛。从疣猪中新分离出的两个基因是捕集蛋白-1（SPAI）和捕集蛋白-2（弹性蛋白酶抑制剂）的直系同源基因，其他的是捕集蛋白家族的新成员，命名为捕集蛋白-6至11。序列差异在编码反应位点的区域最大，内含子序列似乎比蛋白质编码序列更具保守性，尤其是在猪的旁系同源基因中。系统发育分析表明，猪的捕集蛋白多基因家族成员是在猪科（猪和疣猪）和西貒科（领西貒）分化后通过基因复制产生的。与精囊凝血蛋白（REST）和含WAP基序的蛋白在基因结构上的相似性表明，捕集蛋白是通过祖先REST和WAP基序编码基因之间的外显子洗牌产生的天然融合蛋白。
