BIOSYNTHESIS AND MOLECULAR-CLONING OF SULFATED GLYCOPROTEIN-2 SECRETED BY RAT SERTOLI CELLS
BIOSYNTHESIS AND MOLECULAR-CLONING OF SULFATED GLYCOPROTEIN-2 SECRETED BY RAT SERTOLI CELLS
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DOI：
10.1021/bi00386a008
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发表时间：
1987-06-16
期刊：
影响因子：
2.9
通讯作者：
GRISWOLD, MD
中科院分区：
文献类型：
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作者：
COLLARD, MW;GRISWOLD, MD
硫酸化糖蛋白2（Sulfated glycoprotein 2，SGP-2）是大鼠睾丸支持细胞分泌的主要蛋白。脉冲追踪标记表明，SGP-2是作为一个coconstructionally糖基化的64-kDa的前体，被修改为带负电荷的73-kDa的形式，细胞内裂解成熟的47-和34-kDa的亚基之前合成的。从免疫纯化的mRNA构建质粒cDNA文库，并分离含有SGP-2的整个蛋白编码序列的重组克隆。该cDNA全长1857个核苷酸，由297个核苷酸的5“非编码区、1341个核苷酸的编码区和219个核苷酸的3”非编码区组成。5“非编码区含有5个ATG密码子，随后是4个短的开放阅读框。衍生的SGP-2序列具有51，379的分子量，并且含有六个潜在的N-糖基化位点。通过对分离的SGP-2亚基进行氨基末端测序，确定了前原蛋白的蛋白水解加工位点。北方印迹显示2.0-kb SGP-2信使的广泛组织分布，计算机序列分析表明SGP-2和人载脂蛋白A-I之间存在显著关系。
Sulfated glycoprotein 2 (SGP-2) is the major protein secreted by rat Sertoli cells. Pulse-chase labeling shows that SGP-2 is synthesized as a cotranslationally glycosylated 64-kDa precursor that is modified to a negatively charged 73-kDa form before intracellular cleavage to the mature 47- and 34-kDa subunits. A plasmid cDNA library was constructed from immunopurified mRNA, and a recombinant clone containing the entire protein coding sequence of SGP-2 was isolated. The 1857-nucleotide cDNA consists of a 297-nucleotide 5'' noncoding segment, a 1341-nucleotide coding segment, and a 219-nucleotide 3'' noncoding sequence. The 5'' noncoding region contains five ATG codons followed by four short open reading frames. The derived SGP-2 sequence has a molecular weight of 51,379 and contains six potential N-glycosylation sites. Proteolytic processing sites for the preproprotein were determined by amino-terminal sequencing of the isolated SGP-2 subunits. Northern blots show a wide tissue distribution for the 2.0-kb SGP-2 message, and computer sequence analysis indicates a significant relationship between SGP-2 and human apolipoprotein A-I.