title: Unraveling the proteomic profile of mice testis during the initiation of meiosis.
abstract: In mice, once primordial germ cells (PGCs) are generated, they continue to proliferate and migrate to eventually reach the future gonads. They initiate sexual differentiation after their colonization of the gonads. During this process, retinoic acid (RA) induces meiosis in the female germ cells, which proceeds to the diplotene stage of meiotic prophase I, whereas the male germ cells initiate growth arrest. After birth, meiosis is initiated in mice spermatogonia by their conversion to preleptotene spermatocytes. There are evidences showing the roles of RA in the regulation of spermatogonial differentiation and meiosis initiation. However, it is still not well known on what responds to RA and how RA signaling engages meiosis. Thus, we constructed a proteomic profile of proteins associated with meiosis onset during testis development in mouse and identified 104 differentially expressed proteins (≥1.5 folds). Bioinformatic analysis showed proteins functioning in specific cell processes. The expression patterns of five selected proteins were verified via Western blot, of which we found that Tfrc gene was RA responsive, with a RA responsive element, and could be up regulated by RA in spermatogonial stem cell (SSC) line. Taken together, the results provide an important reference profile for further functional study of meiosis initiation.
  
  
  CONCLUSIONS
  Spermatogenesis involves mitosis of spermatogonia, meiosis of spermatocytes and spermiogenesis, in which meiosis is a unique event to germ cells, and not in the somatic cells. Till now, the detailed molecular mechanisms of the transition from mitosis to meiosis are still not elucidated. With high-throughput proteomic technology, it is now possible to systemically identify proteins possibly involved. With TMT-6plex based quantification, we identified 104 proteins differentially between testes without meiosis (day 8.5) and those that were meiosis initiated (day 10.5). And a well-known protein essential for meiosis initiation, stra8, was identified to be differentially expressed in the study. And bioinformatic analysis and functional studies revealed several proteins regulated by retinoic acid, a chemical known to regulate the meiosis initiation. Thus, this quantitative proteomic approach can identify meiosis initiation regulating proteins, and further functional studies of these proteins will help elucidate the mechanisms of meiosis initiation.
authors.affiliation: State Key Laboratory of Reproductive Medicine, Collaborative Innovation Center of Genetics and Development, Department of Histology and Embryology, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Binbin
authors.initials: B
authors.lastname: Shao
authors.affiliation: State Key Laboratory of Reproductive Medicine, Collaborative Innovation Center of Genetics and Development, Department of Histology and Embryology, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Yueshuai
authors.initials: Y
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Reproductive Medicine, Collaborative Innovation Center of Genetics and Development, Department of Histology and Embryology, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Reproductive Medicine, Collaborative Innovation Center of Genetics and Development, Department of Histology and Embryology, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Quan
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Reproductive Medicine, Collaborative Innovation Center of Genetics and Development, Department of Histology and Embryology, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Gao
authors.affiliation: State Key Laboratory of Reproductive Medicine, Collaborative Innovation Center of Genetics and Development, Department of Histology and Embryology, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Reproductive Medicine, Collaborative Innovation Center of Genetics and Development, Department of Histology and Embryology, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Haoyu
authors.initials: H
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Reproductive Medicine, Collaborative Innovation Center of Genetics and Development, Department of Histology and Embryology, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Reproductive Medicine, Collaborative Innovation Center of Genetics and Development, Department of Histology and Embryology, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Zuomin
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Reproductive Medicine, Collaborative Innovation Center of Genetics and Development, Department of Histology and Embryology, Nanjing Medical University, Nanjing 210029, China. Electronic address: guo_xuejiang@njmu.edu.cn.
authors.forename: Xuejiang
authors.initials: X
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Reproductive Medicine, Collaborative Innovation Center of Genetics and Development, Department of Histology and Embryology, Nanjing Medical University, Nanjing 210029, China. Electronic address: bbhxy@njmu.edu.cn.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Reproductive Medicine, Collaborative Innovation Center of Genetics and Development, Department of Histology and Embryology, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Jiahao
authors.initials: J
authors.lastname: Sha
mesh_terms: D000818:Animals; D008297:Male; D008540:Meiosis / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D008813:Mice, Inbred ICR; D020543:Proteome / Q000378:metabolism*; D011990:Receptors, Transferrin / Q000378:metabolism*; D013091:Spermatogenesis / Q000187:drug effects / Q000502:physiology*; D013737:Testis / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D014212:Tretinoin / Q000494:pharmacology*
chemical_list: D020543:Proteome; D011990:Receptors, Transferrin; C480029:Tfrc protein, mouse; D014212:Tretinoin
keywords: Initiation of meiosis; Mice testis; Proteome; Retinoic acid