Song Jiasheng, Li Wanwan, Gao Lulu, Yan Qiang, Zhang Xinyan, Liu Mingzhi, Zhou Shutang
State Key Laboratory of Cotton Bio-breeding and Integrated Utilization, School of Life Sciences, Henan University, Kaifeng, China.
Commun Biol. 2024 Dec 2;7(1):1604. doi: 10.1038/s42003-024-07285-0.
Juvenile hormone (JH) represses insect metamorphosis and stimulates reproduction. JH titers are generally low in juveniles, drop to a nadir during metamorphosis, increase after eclosion and peak in vitellogenic phase. We found that Jhamt, a rate-limiting enzyme in JH biosynthesis, mirrors JH titer patterns in the migratory locust. Knocking down Jhamt reduced JH titers, led to precocious nymphal ecdysis, metamorphosis and impaired vitellogenesis. Jhamt is negatively regulated by miR-276 and positively by miR-182013-5p. miR-276 is abundant in late nymphal but low in adults, while miR-182013-5p shows the opposite pattern. In nymphs, miR-276 binds more to Jhamt, while in adults, miR-182013-5p dominates. Functionally, miR-276 reduced Jhamt and JH levels, shortening nymphal development and inhibiting Vg expression. Conversely, miR-182013-5p increased Jhamt and JH levels, prolonging nymphal development and enhancing Vg expression. Our findings identify miR-276 and miR-182013-5p as dual regulators in JH biosynthesis, acting as "brake" and "accelerator," respectively. This study provides new insights into JH titer fluctuations and miRNA regulation in insect metamorphosis and reproduction.
保幼激素（JH）抑制昆虫变态并刺激繁殖。保幼激素滴度在幼虫期通常较低，在变态期间降至最低点，羽化后升高并在卵黄生成期达到峰值。我们发现，JH生物合成中的限速酶Jhamt反映了飞蝗中的保幼激素滴度模式。敲低Jhamt会降低保幼激素滴度，导致若虫早熟蜕皮、变态并损害卵黄生成。Jhamt受到miR - 276的负调控和miR - 182013 - 5p的正调控。miR - 276在若虫后期含量丰富而在成虫中含量低，而miR - 182013 - 5p则呈现相反的模式。在若虫中，miR - 276与Jhamt的结合更多，而在成虫中，miR - 182013 - 5p占主导地位。在功能上，miR - 276降低了Jhamt和保幼激素水平，缩短了若虫发育并抑制了Vg表达。相反，miR - 182013 - 5p增加了Jhamt和保幼激素水平，延长了若虫发育并增强了Vg表达。我们的研究结果确定miR - 276和miR - 182013 - 5p是JH生物合成中的双重调节因子，分别充当“刹车”和“油门”。本研究为昆虫变态和繁殖过程中的保幼激素滴度波动及miRNA调控提供了新的见解。
