Genetic Innovation of Cytoskeletal Proteins for Specialized Functions in the Male Germline

项目总结 在所有真核生物中，细胞骨架蛋白是许多生物过程中的基础。鉴于他们的 本质上，它们通常被认为是高度保守的。然而，基因创新的签名 以基因家族扩大和加速氨基酸替代的形式在关键 细胞骨架家族成员。亲缘关系密切的物种之间的快速分子分歧是意想不到的 保守的蛋白质家族，表明了序列创新的适应性优势。这项建议 将调查细胞骨架蛋白质这种戏剧性多样化的原因和后果。肌动蛋白- 相关蛋白(Arp)是一种细胞骨架家族，具有古老的进化起源，但具有反复出现的特点 哺乳动物和昆虫的基因创新。与Arp超级家族中保存完好的成员不同， 分歧Arp在表达上是睾丸特有的，这表明它们已经获得了男性的特殊角色 繁殖。然而，推动他们创新的生物过程尚不清楚。配子的本土化 果蝇体内的ARP表明，它们在生殖系特异性肌动蛋白结构中发挥作用。这项提案将解决 配子Arp促进产生对男性生殖至关重要的肌动蛋白结构假说 健身。目标1将揭示在所有果蝇物种中发现的一种配子Arp的功能，Arp53D，它 在精子发生后期定位于两个生殖系肌动蛋白结构。D.Blackogaster，它有许多井- 已建立的遗传工具和只有一个配子Arp，为研究提供了一个有利的系统 不同的Arp在肌动蛋白中的功能，并探索其结构多样化如何允许新的角色。目标2 将分析扩展到哺乳动物的配子Arp，以更深入地了解潜在的共享 推动Arp在多个门类中创新的生物过程。一些证据表明 哺乳动物的配子Arp扮演着肌动蛋白的调节角色，很像Arp53D。目标2将采取全面的 方法来阐明它们的进化史和关于肌动蛋白的定位，同时表征 已建立小鼠基因敲除模型的一种Arp男性不育表型。最后，初步调查结果。 提示在男性中存在更多快速进化的细胞骨架蛋白，而不是ARP 生殖系。Aim 3将系统地搜索果蝇和哺乳动物的基因组以寻找快速进化和基因 睾丸表达丰富的细胞骨架蛋白之间的复制。这一目标将产生额外的 基因创新案例将作为申请者未来实验室的项目，以广泛了解 细胞骨架蛋白的适应性序列可塑性及其驱动雄性生殖专门化的原因。 为了启动这个项目，申请者需要接受生育分析、小鼠睾丸组织学和其他方面的培训 进化论分析。她最终将利用她在生物化学方面的背景来研究细胞骨架的多样化 蛋白质的机械性水平。

PROJECT SUMMARY Cytoskeletal proteins are fundamental in many biological processes among all eukaryotes. Given their essentiality, they are conventionally thought to be highly conserved. However, signatures of genetic innovation in the form of gene-family expansions and accelerated amino-acid substitutions are found among key cytoskeletal family members. Rapid molecular divergence between closely related species is unexpected in conserved protein families and is indicative of an adaptive advantage for sequence innovation. This proposal will investigate the causes and consequences of this dramatic diversification of cytoskeletal proteins. Actin- related proteins (Arps) are one cytoskeletal family that has ancient evolutionary origins yet exhibits recurrent genetic innovation in both mammals and insects. Unlike the well-conserved members of the Arp superfamily, divergent Arps are testis-specific in expression, suggesting they have acquired specialized roles for male reproduction. Yet the biological process that drives their innovation is unknown. The localization of gametic Arps in Drosophila suggests they play roles at germline-specific actin structures. This proposal will address the hypothesis that gametic Arps facilitate the generation of actin structures that are critical for male reproductive fitness. Aim 1 will uncover the function of one gametic Arp found in all Drosophila species, Arp53D, which localizes to two germline actin structures during late spermatogenesis. D. melanogaster, which has many well- established genetic tools and only one gametic Arp, provides an advantageous system in which to investigate the function of a divergent Arp at actin and probe how its structural diversification allows for novel roles. Aim 2 will extend the analysis to mammalian gametic Arps to gain a deeper understanding of the potentially shared biological processes that are driving Arp innovation among multiple phyla. A few pieces of evidence suggest that mammalian gametic Arps play actin regulatory roles, much like Arp53D. Aim 2 will take a comprehensive approach to elucidate their evolutionary histories and localization with respect to actin, while characterizing the male infertility phenotype of one Arp with an established mouse knockout model. Finally, preliminary findings suggest additional cases of rapidly evolving cytoskeletal proteins, beyond Arps, are present in the male germline. Aim 3 will systematically search Drosophila and mammalian genomes for rapid evolution and gene duplications among cytoskeletal proteins that are testis-enriched in expression. This aim will yield additional cases of genetic innovation that will serve as projects in the applicant’s future lab to broadly understand the adaptive sequence plasticity of cytoskeletal proteins and what drives their specialization for male reproduction. To launch this project, the applicant requires training in fertility assays, mouse testis histology and additional evolutionary analyses. She will ultimately use her background in biochemistry to study diversifying cytoskeletal proteins at a mechanistic level.