Ovarian aromatase loss-of-function mutant medaka undergo ovary degeneration and partial female-to-male sex reversal after puberty.
Although estrogens have been generally considered to play a critical role in ovarian differentiation in non-mammalian vertebrates, the specific functions of estrogens during ovarian differentiation remain unclear. We isolated two mutants with premature stops in the ovarian aromatase (cyp19a1) gene from an N-ethyl-N-nitrosourea-based gene-driven mutagenesis library of the medaka, Oryzias latipes. In XX mutants, gonads first differentiated into normal ovaries containing many ovarian follicles that failed to accumulate yolk. Subsequently, ovarian tissues underwent extensive degeneration, followed by the appearance of testicular tissues on the dorsal side of ovaries. In the newly formed testicular tissue, strong expression of gsdf was detected in sox9a2-positive somatic cells surrounding germline stem cells suggesting that gsdf plays an important role in testicular differentiation during estrogen-depleted female-to-male sex reversal. We conclude that endogenous estrogens synthesized after fertilization are not essential for early ovarian differentiation but are critical for the maintenance of adult ovaries.
['Nakamoto|Masatoshi|M|', 'Shibata|Yasushi|Y|', 'Ohno|Kaoru|K|', 'Usami|Takeshi|T|', 'Kamei|Yasuhiro|Y|', 'Taniguchi|Yoshihito|Y|', 'Todo|Takeshi|T|', 'Sakamoto|Takashi|T|', 'Young|Graham|G|', 'Swanson|Penny|P|', 'Naruse|Kiyoshi|K|', 'Nagahama|Yoshitaka|Y|']
D000595:Amino Acid Sequence D000818:Animals D001141:Aromatase D001483:Base Sequence D019070:Cell Lineage D015536:Down-Regulation D004967:Estrogens D005260:Female D020869:Gene Expression Profiling D000073658:Loss of Function Mutation D008297:Male D009990:Oryzias D006080:Ovarian Follicle D010053:Ovary D019849:Sex Determination Processes D012741:Sexual Maturation D013737:Testis D015854:Up-Regulation D014819:Vitellogenins
Aromatase Estrogens Ovarian differentiation cyp19a1 Sex plasticity Teleost fish