Chr23-miR-200s and Dmrt1 Control Sexually Dimorphic Trade-Off Between Reproduction and Growth in Zebrafish

In animals, a trade-off exists between reproduction and growth, which are the most fundamental traits. Males and females exhibit profound differences in reproduction and growth in fish species. However, the precise molecular mechanism governing this phenomenon is still not clear. Here, we uncovered that chr23-miR-200s and <i>dmrt1</i> knockout specifically caused an impairment in reproduction and an increase in body growth in female and male zebrafish, respectively. Chr23-miR-200s and Dmrt1 directly regulate the <i>stat5b</i> gene by targeting its 3'UTR and promoter. The loss of <i>stat5b</i> completely abolished the elevated growth performance in chr23-miR-200s-KO or <i>dmrt1</i>^-/- zebrafish. Moreover, the <i>dmrt1</i> transgenic zebrafish had significantly lower body length and body weight than the control males, accompanied by a significant reduction in <i>stat5b</i> expression in the liver of transgenic fish. In summary, our study proposes a regulatory model elucidating the roles of chr23-miR-200s and Dmrt1 in controlling the sexually dimorphic trade-off between reproduction and growth.