Ringuette M J, Chamberlin M E, Baur A W, Sobieski D A, Dean J
Laboratory of Cellular and Developmental Biology, National Institutes of Health, Bethesda, Maryland 20892.
Dev Biol. 1988 Jun;127(2):287-95. doi: 10.1016/0012-1606(88)90315-6.
At fertilization, mammalian sperm bind is a species-specific manner to the extracellular zona pellucida that surrounds ovulated eggs. ZP3, an 83,000-85,000 Da glycoprotein of the murine zona pellucida, has been shown to inhibit sperm binding via its O-linked oligosaccharide side chains. We have recently isolated cDNA clones coding for ZP3 and have demonstrated that ZP3 transcripts are accumulated in oocytes where their expression is developmentally regulated during oogenesis. We now report that ZP3 mRNA is 1317 nt long with an estimated poly(A) tail of 200-300 nt. The short 29-nt 5' untranslated region is followed by a single open reading frame coding for a polypeptide chain of 46,307 Da which includes six possible sites for N-linked oligosaccharides. The N-terminus of ZP3 contains a potential 22-amino acid signal peptide which upon cleavage would result in a secreted core protein of 43,943 Da. The termination codon is a part of the AATAAA polyadenylation signal and is contained in an unusually short 16-nt 3' untranslated region. Sequences homologous to ZP3 are conserved among mammals and are expressed in ovarian tissue as mature transcripts with indistinguishable molecular weights.
在受精过程中，哺乳动物精子以物种特异性方式与围绕排卵卵子的细胞外透明带结合。小鼠透明带的一种83,000 - 85,000道尔顿的糖蛋白ZP3已被证明通过其O - 连接寡糖侧链抑制精子结合。我们最近分离出了编码ZP3的cDNA克隆，并证明ZP3转录本在卵母细胞中积累，其表达在卵子发生过程中受到发育调控。我们现在报告ZP3 mRNA长1317 nt，估计poly(A)尾长200 - 300 nt。短的29 nt 5'非翻译区后面是一个单一的开放阅读框，编码一条46,307道尔顿的多肽链，其中包括六个可能的N - 连接寡糖位点。ZP3的N端包含一个潜在的22个氨基酸的信号肽，切割后会产生一个43,943道尔顿的分泌核心蛋白。终止密码子是AATAAA聚腺苷酸化信号的一部分，包含在一个异常短的16 nt 3'非翻译区中。与ZP3同源的序列在哺乳动物中保守，并在卵巢组织中作为分子量难以区分的成熟转录本表达。
