The medaka mutant of cyp19a1 (ovarian aromatase) screened by ENU-based gene-driven mutagenesis library of medaka. In this mutant, one amino acid in the cyp19a1 open reading frame altered the stop codon. In the K164X strain, lysine in exon 3 (AAA) was mutated to the stop codon TAA. In the Q183X strain, glutamine in exon 4 (CAG) was altered to the stop codon TAG. The K164X and Q183X strains displayed the same phenotype. In these mutant, the activity of cyp19a1 was lost and thus estrogens in the gonad were extremely reduced. In XX mutants, gonads first differentiated into normal ovaries containing many ovarian follicles that failed to accumulate yolk. Abnormal proliferation of the granulosa cell layers of the ovarian follicles was observed in ovaries. Subsequently, ovarian tissues underwent extensive degeneration, followed by the appearance of testicular tissues on the dorsal side of ovaries.
Nakamoto M, Shibata Y, Ohno K, Usami T, Kamei Y, Taniguchi Y, Todo T, Sakamoto T, Young G, Swanson P, Naruse K, Nagahama Y. Ovarian aromatase loss-of-function mutant medaka undergo ovary degeneration and partial female-to-male sex reversal after puberty. Mol Cell Endocrinol 2018/01/15.460.104-122.
Mutants created by TILLING
National Institute for Basic Biology
Frozen sperm in NIBB
National Institute for Basic Biology, Ehime University