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Separation of Follicular Cells and Oocytes in Ovarian Follicles of Zebrafish
Published on: April 18, 2021
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Igf3 is essential for ovary differentiation in zebrafish†
Yuxin Xie1, Duo Huang1, Lianhe Chu1
1School of Biomedical Sciences, The Chinese University of Hong Kong-Shandong University Joint Laboratory on Reproductive Genetics, The Chinese University of Hong Kong, Shatin, Hong Kong.
Biology of Reproduction
|December 4, 2020
Summary
Insulin-like growth factor 3 (Igf3) is essential for zebrafish ovary development. Loss of Igf3 causes female-to-male sex reversal by disrupting germ cell proliferation and estrogen signaling.
Area of Science:
- Developmental Biology
- Genetics
- Endocrinology
Background:
- Zebrafish gonadal sexual differentiation is complex and not fully understood.
- Insulin-like growth factor 3 (Igf3) has been previously identified in teleosts and linked to oocyte maturation.
Purpose of the Study:
- To investigate the role of Igf3 in zebrafish gonadal sexual differentiation.
- To elucidate the molecular mechanisms underlying Igf3's function in sex determination.
Main Methods:
- Differential expression analysis of igf3 in zebrafish ovaries and testes.
- Generation of an igf3 knockout zebrafish line using TALENs.
- Analysis of gonadal development, germ cell proliferation, and signaling pathways (PI3K/Akt, estrogen).
Main Results:
- igf3 expression is higher in ovaries than testes during differentiation.
- All igf3 homozygous mutants exhibited female-to-male sex reversal.
- Oocyte development arrested at the primary growth stage, and ovaries transformed into testes by 60 days post fertilization.
- Sex reversal was associated with decreased germ cell proliferation via suppression of the PI3K/Akt pathway.
- igf3 expression is upregulated by estrogen, suggesting Igf3 acts downstream of estrogen signaling.
Conclusions:
- Igf3 is indispensable for proper ovary differentiation in zebrafish.
- Disruption of Igf3 leads to sex reversal, impacting germ cell development and proliferation.
- Igf3 functions as a downstream mediator of estrogen signaling in ovarian development.
