Akatsuka K, Yoshida-Komiya H, Tulsiani D R, Orgebin-Crist M C, Hiroi M, Araki Y
Department of Obstetrics and Gynecology, Yamagata University School of Medicine, Yamagata-City, Japan.
Mol Reprod Dev. 1998 Dec;51(4):454-67. doi: 10.1002/(SICI)1098-2795(199812)51:4<454::AID-MRD13>3.0.CO;2-G.
The zona pellucida (ZP), the extracellular glycocalyx that surrounds the oocyte, is well known to mediate homologous gamete interaction. In a previous study from our laboratories, we reported the qualitative characterization of the rat ZP. The ZP in this species, like the mouse, hamster, and human, was found to contain three glycoproteins, namely rZP1, rZP2, and rZP3 (Araki et al. [1992] Biol Reprod 46:912-919). In this study, cDNAs encoding whole rat ZP major components have been isolated and characterized. A rat ovary cDNA library was screened with the mouse ZP3 and ZP2 cDNA probes, respectively. For rZP1 cDNA cloning, cDNAs generated using reverse transcriptase-polymerase chain reaction and rapid amplification of 5' and 3' cDNA ends, were isolated and sequenced. The rZP3 cDNA showed 1338 bp with a coding region containing 1272 bp, that translates into 424 amino acids. The total translation of rZP3 peptide has a molecular weight of 45,820, containing six potential N-glycosylation sites and 75 Ser/Thr residues, possible O-glycosylation sites. The amino acid sequence derived from the cDNA sequence shares high sequence homologies to mouse (90%), hamster (78%), and human (65%) ZP3 (ZPC) glycoproteins, indicating that the rat and mouse ZP3 have quite a conserved amino acid sequence, including the potential glycosylation sites. The total transcript of the rZP2 was 2154 nucleotides and the largest open reading frame was 695 amino acids. This would translate into a protein of 78.4 kDa. In the case of rZP1, the cDNA clone consisted of 1960 bp, and the coding region contained 1851 bp translating into 617 amino acids. Significant homologies were observed between rZP2 and ZPA family from various mammalian species. The rZP1 also showed a sequence homology to mouse ZP1, known as a mouse orthologue of ZPB family, suggesting that the rZP2 and rZP1 are members of ZPA and ZPB families, respectively. The message distributions for each zona components were limited within the ovary and the signal was detectable in the growing oocytes. The present results will further our understanding of the structure of rat zona components and lead to a better understanding of species-specificity observed during sperm-egg interaction.
透明带（ZP）是围绕卵母细胞的细胞外糖萼，众所周知，它介导同源配子间的相互作用。在我们实验室之前的一项研究中，我们报道了大鼠ZP的定性特征。与小鼠、仓鼠和人类一样，该物种的ZP被发现含有三种糖蛋白，即rZP1、rZP2和rZP3（荒木等人，[1992]《生物繁殖》46:912 - 919）。在本研究中，已分离并鉴定了编码大鼠ZP主要成分的cDNA。分别用小鼠ZP3和ZP2 cDNA探针筛选大鼠卵巢cDNA文库。对于rZP1 cDNA克隆，分离并测序了使用逆转录酶 - 聚合酶链反应以及5'和3' cDNA末端快速扩增生成的cDNA。rZP3 cDNA显示为1338 bp，其编码区包含1272 bp，可翻译成424个氨基酸。rZP3肽的总翻译产物分子量为45,820，包含六个潜在的N - 糖基化位点和75个丝氨酸/苏氨酸残基，即可能的O - 糖基化位点。从cDNA序列推导的氨基酸序列与小鼠（90%）、仓鼠（78%）和人类（65%）的ZP3（ZPC）糖蛋白具有高度序列同源性，表明大鼠和小鼠的ZP3具有相当保守的氨基酸序列，包括潜在的糖基化位点。rZP2的总转录本为2154个核苷酸，最大开放阅读框为695个氨基酸。这将翻译成一个78.4 kDa的蛋白质。就rZP1而言，cDNA克隆由1960 bp组成，编码区包含1851 bp，可翻译成617个氨基酸。在rZP2与来自各种哺乳动物物种的ZPA家族之间观察到显著同源性。rZP1也显示出与小鼠ZP1的序列同源性，小鼠ZP1是ZPB家族的小鼠直系同源物，这表明rZP2和rZP1分别是ZPA和ZPB家族的成员。每个透明带成分的信息分布局限于卵巢内，并且在生长中的卵母细胞中可检测到信号。目前的结果将加深我们对大鼠透明带成分结构的理解，并有助于更好地理解在精卵相互作用过程中观察到的物种特异性。
