Structure, Evolutionary Significance, and Developmental Expression of the Sea Urchin Bindin Gene

海洋间受精作用的种特异性 海胆Strongylocentrotus purpuratus和S.弗朗西斯卡努斯群岛 由精子顶体的特异性相互作用控制 蛋白质，结合蛋白，与其受体。 这种相互作用 目前负责维持物种隔离 这两个物种之间的屏障，其地理范围和 繁殖季节重叠。 完整蛋白质的比较 从S. purpuratus和S.方济各会 被用来定义蛋白质序列 这两个物种之间的差异，因此可能是负责 物种特异性结合。 合成肽覆盖这些 区域将用于体外结合测定， 竞争对手在受精，以确定哪些改变 序列负责结合活性的变化。 这两个物种基因组克隆的分析和比较 到第三个物种，Lytechinus variegatus，将显示 重要层序的变化机制和方向。 结合蛋白cDNA克隆也被用作睾丸的标记 幼海胆的发育。 协调控制 bindin和另一个睾丸特异基因，睾丸特异精子 组蛋白H2B，将通过比较它们启动子来研究 序列，并通过确定它们共享的程度 启动子DNA结合蛋白。 %%% 在自然界中，物种由于不育而得以维持， 物种 戴维森博士已经证明，精子蛋白是 负责两种海胆之间的屏障 共享一个栖息地。他们不能杂交，因为他们不能 使其他物种的卵子受精， 无能是由于一种特定的精子蛋白。 博士 戴维森提出了一个分子研究这种蛋白质从 这两个物种，以确定究竟是什么负责 的不兼容性。这两个物种是近亲， 蛋白质在进化过程中明显分化。研究 这里的分子缺陷将提供信息 了解精卵粘附的正常过程， 所有物种的受精过程。

The species specificity of fertilization between the sea urchins Strongylocentrotus purpuratus and S. franciscanus is controlled by the specific interaction of a sperm acrosomal protein, bindin, with its receptor. This interaction is currently responsible for maintaining the species-isolating barrier between these two species, whose geographic ranges and reproductive seasons overlap. Comparisons of complete protein sequences from cDNA clones for S. purpuratus and S. franciscanus are being used to define protein sequences that have changed between the two species and may therefore be responsible for the species-specific binding. Synthetic peptides covering these regions will be used in in vitro binding assays and as competitors in fertilization in order to determine which altered sequences are responsible for the change in binding activity. Analysis of genomic clones from these two species and comparison to a third species, Lytechinus variegatus, will show the mechanism and direction of change for the important sequences. The bindin cDNA clones are also being used as a marker for testis development in juvenile sea urchins. The coordinate control of bindin and another testis specific gene, testis-specific sperm histone H2B, will be studied by comparing their promoter sequences and by determining the extent to which they share promoter DNA binding proteins. %%% In nature species are maintained due to infertility across species. Dr. Davidson has shown that the sperm protein is responsible for this barrier between two species of sea urchins who share a habitat. They can not interbreed due to the inability of the sperm to fertilize the egg of the other species and this inability is due to a species specific sperm protein. Dr. Davidson proposes a molecular investigation of this protein from the two species to determine precisely what is responsible for the incompatibility. The two species are close relatives and this protein has apparently diverged during evolution. The study of the molecular defect here will provide information that will lead to knowledge of the normal process of sperm-egg adhesion, a key event in fertilization in all species.