Myoglianin triggers the premetamorphosis stage in hemimetabolan insects
Myoglianin triggers the premetamorphosis stage in hemimetabolan insects
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DOI：
10.1096/fj.201801511r
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发表时间：
2019-03-01
期刊：
影响因子：
4.8
通讯作者：
Belles, Xavier
中科院分区：
文献类型：
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作者：
Kamsoi, Orathai;Belles, Xavier
昆虫的变态是由幼虫激素（JH）的减少引起的。因此，导致这种减少的原因是一个相关的问题。通过对德国小蠊的研究，我们发现肌球蛋白（Myo）是TGF-信号通路中的一种配体，在第二（第五）若虫期（N5），肌球蛋白（Myo）在偶体（CA，产生jh的腺体）和前胸腺（PG）中高度表达。在CA中，N5期间的高Myo水平抑制了幼鱼激素酸甲基转移酶（JH生物合成基因）的表达。在PG中，JH水平的降低触发腺体退化，受Kruppel同源物1、fz - f1、E93和凋亡抑制剂-1的调节。同样在PG中，N5中myo的表达高峰间接刺激了蜕皮激素生物合成基因如neverland的表达，增强了N6中变质蜕皮激素脉冲的产生。N5中Myo的表达高峰也抑制了细胞的增殖，促进了蜕皮激素的产生。这些数据表明Myo在德国小蠊和其他半代谢昆虫中触发了预变质若虫。肌球蛋白触发半代谢昆虫的前变态阶段。
Insect metamorphosis is triggered by a decrease in juvenile hormone (JH) in the final juvenile instar. What induces this decrease is therefore a relevant question. Working with the cockroach Blattella germanica, we found that myoglianin (Myo), a ligand in the TGF- signaling pathway, is highly expressed in the corpora allata (CA, the JH-producing glands) and the prothoracic gland [(PG), which produce ecdysone] during the penultimate (fifth) nymphal instar (N5). In the CA, high Myo levels during N5 repress the expression of juvenile hormone acid methyl transferase, a JH biosynthesis gene. In the PG, decreasing JH levels trigger gland degeneration, regulated by the factors Kruppel homolog 1, FTZ-F1, E93, and inhibitor of apoptosis-1. Also in the PG, a peak of myo expression in N5 indirectly stimulates the expression of ecdysone biosynthesis genes, such as neverland, enhancing the production of the metamorphic ecdysone pulse in N6. The Myo expression peak in N5 also represses cell proliferation, which can enhance ecdysone production. The data indicate that Myo triggers the premetamorphic nymphal instar in B. germanica and possibly in other hemimetabolan insects.Kamsoi, O., Belles, X. Myoglianin triggers the premetamorphosis stage in hemimetabolan insects.