Proteomic Analysis of Pachytene Spermatocytes of Sterile Hybrid Male Mice

Abstract

Incompatibilities in interspecific hybrids, such as reduced hybrid fertility and lethality, are common features resulting from reproductive isolation that lead to speciation. Subspecies crosses of house mice produce offspring in which one sex is infertile or absent, yet the molecular mechanisms of hybrid sterility are poorly understood. In this study, we observed extensive asynapsis of chromosomes and disturbance of the sex body in pachytene spermatocytes of sterile F1 males (PWK/Ph female × C57BL/6J male). We report the high-confidence identification of 4005 proteins in the pachytene spermatocytes of fertile F1 males (PWK/Ph male × C57BL/6J female) and sterile F1 males (PWK/Ph female × C57BL/6J male), of which 215 were upregulated and 381 were downregulated. Bioinformatics analysis of the proteome led to the identification of 43 and 59 proteins known to be essential for male meiosis and spermatogenesis in mice, respectively. Characterization of the proteome of pachytene spermatocytes associated with hybrid male sterility provides an inventory of proteins that is useful for understanding meiosis and the mechanisms of hybrid male infertility.

Prediction and Validation of Mouse Meiosis-Essential Genes Based on Spermatogenesis Proteome Dynamics

“…Proteomic investigations of the entire mouse testis and one type of meiotic cells, pachytene by guest on December 6, 2020 spermatocytes, have been accomplished in several labs (7,18,48). However, without isolation of different types of meiotic cells, these studies could not generate a precise picture of the different stages of mouse meiosis.…”

“…It is accepted that mammalian meiosis is a complex process that includes several molecular events, including homologous recombination, synapsis and so on, whereas the genes involved in these events are not well characterized in mammals (1)(2). In contrast, the genes participating in yeast meiosis are well studied, and thus, homology comparisons between yeast and mammals is a common strategy to investigate meiotic genes such as Spo11, Dmc1, Psmc3ip, and Rnf212 (3)(4)(5)(6)(7). Since the regulatory mechanism of mammalian meiosis is more complicated than that of yeast, the genes specifically related to mammalian meiosis cannot be found through such a comparison strategy.…”

“…molecules with certain functions. The investigation towards spermatogenesis using proteomics is still unsatisfactory, even though a report exists regarding the quantitative proteomics in relation to pachytene spermatocytes (7,18). Hence, a comprehensive proteomics study of the different cell types of male meiosis is proposed.…”

Prediction of meiosis-essential genes based on dynamic proteomes responsive to spermatogenesis

“…How to obtain such information is a long-lasting question. The proteomic investigation towards the entire mouse testis and one type of meiotic cells-Pachytene spermatocytes have been accomplished in several labs 7,17,35 . However, without isolation of different types of meiotic cells, these studies could not generate a precise picture into the different stages of mouse meiosis.…”

“…It is well accepted that mammalian meiosis is a complex process including homologous recombination, synapsis and so on, while the molecular mechanisms involved in such process are still to be explored yet 1,2 . Since the genes participating in yeast meiosis are well studied, homology comparison to yeast is a common strategy to scrutinize the meiotic mechanism of mammalian (e.g., such as Spo11, Dmc1, Psmc3ip, and Rnf212) [3][4][5][6][7] . On the other hand, the regulatory mechanism of mammalian meiosis is more complicated than that of yeast, and the genes specifically participated in mammalian meiosis could not be found by this strategy.…”