ABALONE EGG COAT PROTEINS

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 含有透明带(ZP)结构域的蛋白质是脊椎动物卵壳的重要组成部分。无脊椎动物腹足类鲍鱼(Haliotis spp.)也是已知的含有ZP结构域的蛋白，这增加了后生动物卵壳结构具有共同分子基础的可能性。脊椎动物和无脊椎动物类群的卵壳蛋白已被证明在正向选择下进化。在鲍鱼系统中研究最广泛的是适应性发散的卵壳和精子蛋白之间的协同进化，这可能有助于生殖隔离的快速发展。因此，识别蛋壳蛋白之间的进化模式对于理解这些基因在物种形成过程中可能发挥的作用是重要的。本研究的目的是对鲍卵卵壳(卵黄膜，VE)的组成蛋白进行表征，并为鲍鱼进化过程中选择对VE蛋白的作用提供初步证据。我们使用蛋白质组学方法将纯化的VE蛋白的多肽与鲍鱼卵巢EST序列进行串联质谱匹配，并从10个新的ZP结构域蛋白中鉴定出9个是VE的组成成分。密码子进化的最大似然模型表明，这些基因中的6个在氨基酸子集中发挥了正向选择作用。这项工作进一步证明了ZP蛋白作为卵壳成分的重要性，以及正选择在这些生殖蛋白多样化中的突出作用。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Proteins harboring a zona pellucida (ZP) domain are prominent components of vertebrate egg coats. Although less well characterized, the egg coat of the invertebrate marine gastropod abalone (Haliotis spp.) is also known to contain a ZP domain protein, raising the possibility of a common molecular basis of metazoan egg coat structures. Egg coat proteins from vertebrate as well as invertebrate taxa have been shown to evolve under positive selection. Studied most extensively in the abalone system, coevolution between adaptively diverging egg coat and sperm proteins may contribute to the rapid development of reproductive isolation. Thus identifying the pattern of evolution among egg coat proteins is important in understanding the role these genes may play in the speciation process. The purpose of the present study is to characterize the constituent proteins of the egg coat (vitelline envelope, VE) of abalone eggs, and to provide preliminary evidence regarding how selection has acted on VE proteins during abalone evolution. We use a proteomic approach to match tandem mass spectra of peptides from purified VE proteins with abalone ovary EST sequences, and identify 9 of 10 novel ZP domain proteins as components of the VE. Maximum likelihood models of codon evolution suggest positive selection has acted among a subset of amino acids for 6 of these genes. This work provides further evidence of the prominence of ZP proteins as constituents of the egg coat, as well as the prominent role of positive selection in diversification of these reproductive proteins.