Germ cells are required to maintain a stable sexual phenotype in adult zebrafish.
Sex in zebrafish is not determined by a major chromosomal locus, but instead relies on a mechanism that is influenced by a germ cell-derived signal, as animals that lack germ cells, or specifically oocytes, develop as phenotypic males. These data suggest that during primary sex determination, an oocyte-derived signal acts on the bipotential somatic gonad to promote the female-specific program. However, it is not known if germ cells are required only during the primary sex-determining window, or if they are required throughout adult life to maintain the female sexual phenotype. Here, we show that while wild-type zebrafish do not switch sex as adults, germ cell-depleted adult females readily convert to a male phenotype. Notably, when oocytes are depleted, but germline stem cells remain, adult females sex-revert to sperm-producing males, indicating that a germ cell-derived signal acts on the somatic gonad to promote female development directly or indirectly by repressing male-specific gene expression. These results also confirm that signals from the somatic gonad in turn ensure that the sex appropriate gamete is produced.
Department of Molecular and Cellular Biology, University of California Davis, One Shields Avenue, Davis, CA 95616, USA.
Daniel B
DB
Dranow
Richard P
RP
Tucker
Bruce W
BW
Draper
D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology*; D005854:Germ Cells / Q000166:cytology / Q000378:metabolism*; D006652:Histological Techniques; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008297:Male; D008795:Metronidazole; D008954:Models, Biological; D008969:Molecular Sequence Data; D010641:Phenotype; D010957:Plasmids / Q000235:genetics; D019849:Sex Determination Processes / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism*; D015027:Zebrafish / Q000196:embryology*
D008795:Metronidazole