Junior Research Group Antibody Technologies, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany.
Mol Reprod Dev. 2012 Aug;79(8):517-24. doi: 10.1002/mrd.22056. Epub 2012 Jun 29.
Sperm proteins of marine sessile invertebrates have been extensively studied to understand the molecular basis of reproductive isolation. Apart from molecules such as bindin of sea urchins or lysin of abalone species, the acrosomal protein M7 lysin of Mytilus edulis has been analyzed. M7 lysin was found to be under positive selection, but mechanisms driving the evolution of this protein are not fully understood. To explore functional aspects, this study investigated the protein expression pattern of M7 and M6 lysin in gametes and somatic tissue of male and female M. edulis. The study employs a previously published monoclonal antibody (G26-AG8) to investigate M6 and M7 lysin protein expression, and explores expression of both genes. It is shown that these proteins and their encoding genes are expressed in gametes and somatic tissue of both sexes. This is in contrast to sea urchin bindin and abalone lysin, in which gene expression is strictly limited to males. Although future studies need to clarify the functional importance of both acrosomal proteins in male and female somatic tissue, new insights into the evolution of sperm proteins in marine sessile invertebrates are possible. This is because proteins with male-specific expression (bindin, lysin) might evolve differently than proteins with expression in both sexes (M6/M7 lysin), and the putative function of both proteins in females opens the possibility that the evolution of M6/M7 lysin is under sexual antagonistic selection, for example, mutations beneficial to the acrosomal function that are less beneficial the function in somatic tissue of females.
海洋固着无脊椎动物的精子蛋白已被广泛研究，以了解生殖隔离的分子基础。除了海胆的结合蛋白或鲍鱼物种的溶菌酶等分子外，还分析了贻贝的顶体蛋白 M7 溶菌酶。发现 M7 溶菌酶受到正选择，但驱动该蛋白进化的机制尚不完全清楚。为了探索功能方面，本研究调查了 M. edulis 雌雄配子和体细胞中 M7 和 M6 溶菌酶的蛋白表达模式。该研究使用先前发表的单克隆抗体 (G26-AG8) 来研究 M6 和 M7 溶菌酶蛋白表达，并探索这两个基因的表达。结果表明，这些蛋白及其编码基因在雌雄配子和体细胞中均有表达。这与海胆结合蛋白和鲍鱼溶菌酶形成对比，后两者的基因表达严格限于雄性。尽管未来的研究需要阐明两性体细胞中这两种顶体蛋白的功能重要性，但对于海洋固着无脊椎动物精子蛋白的进化可能会有新的认识。这是因为具有雄性特异性表达的蛋白（结合蛋白、溶菌酶）可能与在两性中表达的蛋白（M6/M7 溶菌酶）进化方式不同，并且这两种蛋白在雌性中的假定功能使得 M6/M7 溶菌酶的进化可能受到性拮抗选择的影响，例如，有利于顶体功能的突变在雌性体细胞功能中不太有利。
