Department of Evolution and Ecology, University of California, Davis, CA 95616.
Proc Natl Acad Sci U S A. 2024 Oct 29;121(44):e2409850121. doi: 10.1073/pnas.2409850121. Epub 2024 Oct 25.
Sexual reproduction requires the choreographed interaction of female cells and molecules with sperm and seminal fluid. In internally fertilizing animals, these interactions are managed by specialized tissues within the female reproductive tract (FRT), such as a uterus, glands, and sperm storage organs. However, female somatic reproductive tissues remain understudied, hindering insight into the molecular interactions that support fertility. Here, we report the identification, molecular characterization, and analysis of cell types throughout the somatic FRT in the premier model system. We find that the uterine epithelia is composed of 11 distinct cell types with well-delineated spatial domains, likely corresponding to functionally specialized surfaces that interact with gametes and reproductive fluids. Polyploidy is pervasive: More than half of lower reproductive tract cells are ≥4C. While seminal fluid proteins (SFPs) are typically thought of as male products that are transferred to females, we find that specialized cell types in the sperm storage organs heavily invest in expressing SFP genes. Rates of amino acid divergence between closely related species indicate heterogeneous evolutionary processes acting on male-limited versus female-expressed seminal fluid genes. Together, our results emphasize that more than 40% of annotated seminal fluid genes are better described as shared components of reproductive transcriptomes, which may function cooperatively to support spermatozoa. More broadly, our work provides the molecular foundation for improved technologies to catalyze the functional characterization of the FRT.
有性生殖需要雌性细胞和分子与精子和精液的精心协调互动。在体内受精的动物中，这些相互作用由雌性生殖道（FRT）内的专门组织管理，如子宫、腺体和精子储存器官。然而，雌性体细胞生殖组织仍未得到充分研究，这阻碍了对支持生育的分子相互作用的深入了解。在这里，我们报告了在主要模型系统中对整个体细胞 FRT 中的细胞类型的鉴定、分子特征分析和分析。我们发现，子宫上皮由 11 种不同的细胞类型组成，具有明确的空间域，可能对应于与配子和生殖液相互作用的功能特化表面。多倍体是普遍存在的：超过一半的下生殖道细胞是≥4C。虽然精液蛋白（SFP）通常被认为是传递给雌性的雄性产物，但我们发现精子储存器官中的专门细胞类型大量投入表达 SFP 基因。密切相关物种之间氨基酸分歧率表明，作用于雄性限制与雌性表达精液基因的不均匀进化过程。总之，我们的研究结果强调，超过 40%的注释精液基因更准确地描述为生殖转录组的共享成分，这些成分可能共同作用以支持精子。更广泛地说，我们的工作为改进技术提供了分子基础，以促进 FRT 的功能特征描述。
