In order to produce sperm, progenitor germ cells in the testes must undergo mitosis, meiosis, differentiation, and alter their chromatin structure to give rise to functional gametes. Much of our knowledge about how this complex process is controlled in humans is extrapolated from studies performed on mice, despite the fact that spermatogenesis may differ between species. On p. 3659, Sjoerd Repping and colleagues combine laser-capture microdissection and next-generation RNA sequencing techniques to provide the first detailed analysis of the gene expression patterns of spermatogenic cells isolated from human tissue. They profile the transcriptomes of six functionally distinct classes of germ cells from the human testis, which represent successive steps in the process of spermatogenesis. They find that over 4000 genes are dynamically transcribed throughout this process, including a significant number of post-transcriptional regulators such as RNA-binding proteins and long non-coding RNAs. These data suggest that post-transcriptional regulatory mechanisms are important for the transition of germ cells from a precursor state into differentiated sperm. This work provides valuable insight into how the process of sperm production differs between humans and other species at a transcriptional level, and should serve as an important resource for identifying genes implicated in male infertility.
