Conservation of the egg envelope digestion mechanism of hatching enzyme in euteleostean fishes
Conservation of the egg envelope digestion mechanism of hatching enzyme in euteleostean fishes
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DOI：
10.1111/j.1742-4658.2010.07907.x
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发表时间：
2010-12-01
期刊：
影响因子：
5.4
通讯作者：
Nishida, Mutsumi
中科院分区：
文献类型：
--
作者：
Kawaguchi, Mari;Yasumasu, Shigeki;Nishida, Mutsumi
从异卵底孵化液中分离纯化了两种孵化酶，即高绒膜溶解酶（HCE; EC 3.4.24.67）和低绒膜溶解酶（LCE; EC 3.4.24.66），分别命名为底HCE（FHCE）和底LCE（FLCE）。FHCE使卵被膜内层膨胀，FLCE完全消化膨胀的卵被膜。此外，我们克隆了三个底的cDNA的cDNA序列的青鳉前体的卵包膜亚基蛋白（即绒膜蛋白H，H小和L）从女性的肝脏。通过比较FHCE和FLCE的N-末端氨基酸序列与从卵被膜亚基蛋白cDNA推导的序列，确定了FHCE和FLCE在卵被膜亚基蛋白上的切割位点。FHCE和FLCE切割亚基蛋白的不同位点。FHCE有效地将Pro-X-Y重复区切割成三肽至十二肽以使包膜膨胀，而FLCE切割卵包膜亚基蛋白的核心结构--透明质酸结构域的内部以完全消化FHCE膨胀的包膜。比较结果表明，底和青鳉卵被膜亚基蛋白上的孵化酶切割位点的位置是严格保守的。最后，我们将这种比较扩展到其他三种真骨鱼类（即三棘鱼，斑点大比目鱼和虹鳟鱼），发现它们之间的卵包膜消化机制是很好的保守。在进化过程中，HCE和LCE直系同源物对卵被膜的消化作用在真硬骨鱼谱系中得到了确立，其机制可能是保守的。
We purified two hatching enzymes, namely high choriolytic enzyme (HCE; EC 3.4.24.67) and low choriolytic enzyme (LCE; EC 3.4.24.66), from the hatching liquid of Fundulus heteroclitus, which were named Fundulus HCE (FHCE) and Fundulus LCE (FLCE). FHCE swelled the inner layer of egg envelope, and FLCE completely digested the FHCE-swollen envelope. In addition, we cloned three Fundulus cDNAs orthologous to cDNAs for the medaka precursors of egg envelope subunit proteins (i.e. choriogenins H, H minor and L) from the female liver. Cleavage sites of FHCE and FLCE on egg envelope subunit proteins were determined by comparing the N-terminal amino acid sequences of digests with the sequences deduced from the cDNAs for egg envelope subunit proteins. FHCE and FLCE cleaved different sites of the subunit proteins. FHCE efficiently cleaved the Pro-X-Y repeat regions into tripeptides to dodecapeptides to swell the envelope, whereas FLCE cleaved the inside of the zona pellucida domain, the core structure of egg envelope subunit protein, to completely digest the FHCE-swollen envelope. A comparison showed that the positions of hatching enzyme cleavage sites on egg envelope subunit proteins were strictly conserved between Fundulus and medaka. Finally, we extended such a comparison to three other euteleosts (i.e. three-spined stickleback, spotted halibut and rainbow trout) and found that the egg envelope digestion mechanism was well conserved among them. During evolution, the egg envelope digestion by HCE and LCE orthologs was established in the lineage of euteleosts, and the mechanism is suggested to be conserved.