Song Jiasheng, Wu Zhongxia, Wang Zhiming, Deng Shun, Zhou Shutang
State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
School of Life Sciences, University of Science and Technology of China, Hefei, 230027, China.
Insect Biochem Mol Biol. 2014 Sep;52:94-101. doi: 10.1016/j.ibmb.2014.07.001. Epub 2014 Jul 10.
Juvenile hormone (JH) prevents insect larval metamorphosis and stimulates processes for adult reproduction. Krüppel-homolog 1 (Kr-h1), a zinc finger transcription factor, is shown to mediate the anti-metamorphic effect of JH in both holometabolous and hemimetabolous insects. However, the role of Kr-h1 in JH-mediated reproduction has not been determined. Using the migratory locust, Locusta migratoria, we showed here that Kr-h1 was expressed in response to JH in female adults, and Kr-h1 transcription was directly regulated by the JH-receptor complex comprised of Methoprene-tolerant (Met) and steroid receptor co-activator. We demonstrated that Kr-h1 RNAi phenocopied Met RNAi and JH-deprived condition during post-eclosion development and vitellogenesis of female locusts. Knockdown of Kr-h1 resulted in substantial reduction of Vg expression in the fat body and lipid accumulation in the primary oocytes, accompanied by blocked follicular epithelium development, oocyte maturation and ovarian growth. Our data therefore reveal a crucial role of Kr-h1 in insect vitellogenesis and egg production. This study suggests that JH-Met-Kr-h1 signaling pathway is also functional in insect reproduction.
保幼激素（JH）可阻止昆虫幼虫变态，并刺激成虫的繁殖过程。Krüppel同源物1（Kr-h1）是一种锌指转录因子，已被证明在全变态昆虫和不完全变态昆虫中均介导JH的抗变态作用。然而，Kr-h1在JH介导的生殖中的作用尚未确定。我们利用飞蝗（Locusta migratoria）证明，成年雌性飞蝗中Kr-h1的表达受JH诱导，且Kr-h1的转录直接受由耐甲氧普烯（Met）和类固醇受体共激活因子组成的JH受体复合物调控。我们证明，在雌性飞蝗羽化后发育和卵黄发生过程中，Kr-h1 RNA干扰模拟了Met RNA干扰和JH剥夺的情况。敲低Kr-h1导致脂肪体中Vg表达大幅减少，初级卵母细胞中脂质积累，同时伴有卵泡上皮发育、卵母细胞成熟和卵巢生长受阻。因此，我们的数据揭示了Kr-h1在昆虫卵黄发生和产卵中的关键作用。本研究表明，JH-Met-Kr-h1信号通路在昆虫生殖中也发挥作用。
