title: Knockout of Zebrafish Ovarian Aromatase Gene (cyp19a1a) by TALEN and CRISPR/Cas9 Leads to All-male Offspring Due to Failed Ovarian Differentiation.
abstract: Sexual or gonadal differentiation is a complex event and its mechanism remains elusive in teleosts. Despite its complexity and plasticity, the process of ovarian differentiation is believed to involve gonadal aromatase (cyp19a1a) in nearly all species studied. However, most data concerning the role of aromatase have come from gene expression analysis or studies involving pharmacological approaches. There has been a lack of genetic evidence for the importance of aromatase in gonadal differentiation, especially the timing when the enzyme starts to exert its effect. This is due to the lack of appropriate loss-of-function approaches in fish models for studying gene functions. This situation has changed recently with the development of genome editing technologies, namely TALEN and CRISPR/Cas9. Using both TALEN and CRISPR/Cas9, we successfully established three mutant zebrafish lines lacking the ovarian aromatase. As expected, all mutant fish were males, supporting the view that aromatase plays a critical role in directing ovarian differentiation and development. Further analysis showed that the ovarian aromatase did not seem to affect the formation of so-called juvenile ovary and oocyte-like germ cells; however, it was essential for further differentiation of the juvenile ovary into the true ovary.
authors.affiliation: School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
authors.forename: Esther Shuk-Wa
authors.initials: ES
authors.lastname: Lau
authors.affiliation: Centre of Reproduction, Development and Aging (CRDA), Faculty of Health Sciences, University of Macau, Taipa, Macau, China.
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Centre of Reproduction, Development and Aging (CRDA), Faculty of Health Sciences, University of Macau, Taipa, Macau, China.
authors.forename: Mingming
authors.initials: M
authors.lastname: Qin
authors.affiliation: School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.|Centre of Reproduction, Development and Aging (CRDA), Faculty of Health Sciences, University of Macau, Taipa, Macau, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Ge
mesh_terms: D000818:Animals; D001141:Aromatase / Q000235:genetics* / Q000378:metabolism; D064113:CRISPR-Cas Systems; D002454:Cell Differentiation / Q000235:genetics*; D005260:Female; D000072669:Gene Editing / Q000379:methods; D055786:Gene Knockout Techniques / Q000379:methods; D000073658:Loss of Function Mutation; D008297:Male; D009865:Oocytes / Q000166:cytology / Q000378:metabolism; D010053:Ovary / Q000166:cytology / Q000378:metabolism*; D012737:Sex Factors; D000069896:Transcription Activator-Like Effector Nucleases / Q000378:metabolism*; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D029961:Zebrafish Proteins; D001141:Aromatase; C440729:Cyp19a1a protein, zebrafish; D000069896:Transcription Activator-Like Effector Nucleases