title: Early depletion of primordial germ cells in zebrafish promotes testis formation.
abstract: As complete absence of germ cells leads to sterile males in zebrafish, we explored the relationship between primordial germ cell (PGC) number and sexual development. Our results revealed dimorphic proliferation of PGCs in the early zebrafish larvae, marking the beginning of sexual differentiation. We applied morpholino-based gene knockdown and cell transplantation strategies to demonstrate that a threshold number of PGCs is required for the stability of ovarian fate. Using histology and transcriptomic analyses, we determined that zebrafish gonads are in a meiotic ovarian stage at 14 days postfertilization and identified signaling pathways supporting meiotic oocyte differentiation and eventual female fate. The development of PGC-depleted gonads appears to be restrained and delayed, suggesting that PGC number may directly regulate the variability and length of gonadal transformation and testicular differentiation in zebrafish. We propose that gonadal transformation may function as a developmental buffering mechanism to ensure the reproductive outcome.
authors.affiliation: Reproductive Genomics Group, Strategic Research Program, Temasek Life Sciences Laboratory, Singapore 117604, Singapore. Electronic address: kehweei.tzung@gmail.com.
authors.forename: Keh-Weei
authors.initials: KW
authors.lastname: Tzung
authors.affiliation: Nanae Fresh Water Laboratory, Field Science Center for Northern Biosphere, Hokkaido University, Nanae, Kameda, Hokkaido 041-1105, Japan.
authors.forename: Rie
authors.initials: R
authors.lastname: Goto
authors.affiliation: Reproductive Genomics Group, Strategic Research Program, Temasek Life Sciences Laboratory, Singapore 117604, Singapore.
authors.forename: Jolly M
authors.initials: JM
authors.lastname: Saju
authors.affiliation: Reproductive Genomics Group, Strategic Research Program, Temasek Life Sciences Laboratory, Singapore 117604, Singapore.
authors.forename: Rajini
authors.initials: R
authors.lastname: Sreenivasan
authors.affiliation: Nanae Fresh Water Laboratory, Field Science Center for Northern Biosphere, Hokkaido University, Nanae, Kameda, Hokkaido 041-1105, Japan.
authors.forename: Taiju
authors.initials: T
authors.lastname: Saito
authors.affiliation: Faculty of Fisheries Sciences, Hokkaido University, Hakodate, Hokkaido 041-8611, Japan.
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Arai
authors.affiliation: Nanae Fresh Water Laboratory, Field Science Center for Northern Biosphere, Hokkaido University, Nanae, Kameda, Hokkaido 041-1105, Japan.
authors.forename: Etsuro
authors.initials: E
authors.lastname: Yamaha
authors.affiliation: Reproductive Genomics Group, Strategic Research Program, Temasek Life Sciences Laboratory, Singapore 117604, Singapore.
authors.forename: Mohammad Sorowar
authors.initials: MS
authors.lastname: Hossain
authors.affiliation: Bioimaging and Biocomputing Facility, Temasek Life Sciences Laboratory, Singapore 117604, Singapore.
authors.forename: Meredith E K
authors.initials: MEK
authors.lastname: Calvert
authors.affiliation: Reproductive Genomics Group, Strategic Research Program, Temasek Life Sciences Laboratory, Singapore 117604, Singapore; Department of Animal Sciences and Animal Husbandry, Georgikon Faculty, University of Pannonia, 8360 Keszthely, Hungary; Centre for Comparative Genomics, Murdoch University, Murdoch, WA 6150, Australia. Electronic address: laszlo@tll.org.sg.
authors.forename: László
authors.initials: L
authors.lastname: Orbán
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D049109:Cell Proliferation; D016000:Cluster Analysis; D004625:Embryo, Nonmammalian; D005260:Female; D020869:Gene Expression Profiling; D005854:Germ Cells / Q000166:cytology* / Q000378:metabolism*; D006066:Gonads / Q000166:cytology / Q000196:embryology* / Q000378:metabolism*; D007814:Larva; D008297:Male; D008540:Meiosis; D008954:Models, Biological; D015203:Reproducibility of Results; D012727:Sex Characteristics; D012733:Sex Differentiation; D015398:Signal Transduction; D013997:Time Factors; D059467:Transcriptome; D016212:Transforming Growth Factor beta / Q000378:metabolism; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics / Q000378:metabolism*
chemical_list: D016212:Transforming Growth Factor beta