【摘要】 研究了一个新的人分泌蛋白基因_分泌粒蛋白III(secretograninIII,SgIII)。SgIII蛋白序列共有 4 6 8个氨基酸残基 ,N端有一段疏水信号肽 ,序列中含有DSTK重复序列和 7对二元碱性氨基酸 (dibasicsites) ,这些结构特点同其他分泌粒蛋白家族成员相类似。人源SgIII蛋白在小鼠、大鼠和爪蟾中各有一个同源蛋白。基因组分析表明 ,SgIII基因位于人 15号染色体上 ,含有 12个外显子 ,分布在 39kb长的基因组DNA上。Western印迹和免疫细胞化学实验证实 ,SgIII蛋白同其他分泌粒蛋白家族成员一样 ,通过分泌途径被分泌到胞外。SgIII在多种组织中都有表达 ,Northern印迹显示SgIII的mRNA主要有 2 .2kb和 1.9kb两种形式 ,但在脑中还有 4 .5kb和 3.3kb大小的两种特异转录本。更多还原

【Abstract】 We have cloned a new member of the granin family, termed human secretogranin III (SgIII), that encodes 468 amino acid residues. The human SgIII protein possesses an N terminal signal peptide, seven dibasic sites, and the repeated DSTK sequences. These structure characteristics are similar to other members of secretogranin family. The human SgIII has homologous proteins in mouse, rat , and Xenopus laevis . Genomic organization shows the gene includes 12 coding exons spanning 39 kb of genomic DNA on the human chromosome 15. Human SgIII is expressed widely as showed in Northern blot and its cDNA hybridizes to 2.2 kb and 1.9 kb bands in many tissues, with two additional 4.5 kb and 3.3 kb bands in brain. Subcelluar localization and immunoblotting indicated SgIII was secreted out of cell through trans Golgi network (TGN). SgIII may take effect in the biogenesis of secretory granules as a helper protein and be involved in the production or release of peptide hormones in the regulated secretory pathway.更多还原