A Comprehensive Roadmap of Murine Spermatogenesis Defined by Single-Cell RNA-Seq

Spermatogenesis requires intricate interactions between the germline and somatic cells. Within a given cross section of a seminiferous tubule, multiple germ and somatic cell types co-occur. This cellular heterogeneity has made it difficult to profile distinct cell types at different stages of development. To address this challenge, we collected single-cell RNA sequencing data from ∼35,000 cells from the adult mouse testis and identified all known germ and somatic cells, as well as two unexpected somatic cell types. Our analysis revealed a continuous developmental trajectory of germ cells from spermatogonia to spermatids and identified candidate transcriptional regulators at several transition points during differentiation. Focused analyses delineated four subtypes of spermatogonia and nine subtypes of Sertoli cells; the latter linked to histologically defined developmental stages over the seminiferous epithelial cycle. Overall, this high-resolution cellular atlas represents a community resource and foundation of knowledge to study germ cell development and in vivo gametogenesis. [Display omitted] •Analysis of ∼35,000 cells identifies known and unexpected mouse testicular cell types•Germ cell development includes discrete states followed by a continuous trajectory•Differential gene expression identifies new regulators of spermatogenesis•Four spermatogonia subtypes and nine Sertoli cell subtypes map to known stages Male germ cell development requires intricate interplay between mitotic, meiotic, and differentiating germ cells and supporting somatic cells. Green et al. apply single-cell RNA sequencing to generate a mouse spermatogenesis resource to untangle cellular heterogeneity within the adult testis, identify regulators of germ cell differentiation, and discover somatic cell types.