Institute of Insect Sciences, Zhejiang University, Hangzhou, China.
State Key laboratory of Rice Biology, Zhejiang University, Hangzhou, China.
PLoS Genet. 2021 Jun 28;17(6):e1009653. doi: 10.1371/journal.pgen.1009653. eCollection 2021 Jun.
A single insulin receptor (InR) gene has been identified and extensively studied in model species ranging from nematodes to mice. However, most insects possess additional copies of InR, yet the functional significance, if any, of alternate InRs is unknown. Here, we used the wing-dimorphic brown planthopper (BPH) as a model system to query the role of a second InR copy in insects. NlInR2 resembled the BPH InR homologue (NlInR1) in terms of nymph development and reproduction, but revealed distinct regulatory roles in fuel metabolism, lifespan, and starvation tolerance. Unlike a lethal phenotype derived from NlInR1 null, homozygous NlInR2 null mutants were viable and accelerated DNA replication and cell proliferation in wing cells, thus redirecting short-winged-destined BPHs to develop into long-winged morphs. Additionally, the proper expression of NlInR2 was needed to maintain symmetric vein patterning in wings. Our findings provide the first direct evidence for the regulatory complexity of the two InR paralogues in insects, implying the functionally independent evolution of multiple InRs in invertebrates.
一个单一的胰岛素受体（InR）基因已经在从线虫到老鼠的模型物种中被鉴定和广泛研究。然而，大多数昆虫都有额外的 InR 拷贝，但替代 InR 的功能意义（如果有的话）尚不清楚。在这里，我们使用翅膀二型性褐飞虱（BPH）作为模型系统来研究第二个 InR 拷贝在昆虫中的作用。NlInR2 在若虫发育和繁殖方面与 BPH InR 同源物（NlInR1）相似，但在燃料代谢、寿命和饥饿耐受方面表现出不同的调节作用。与 NlInR1 缺失导致的致命表型不同，纯合的 NlInR2 缺失突变体是存活的，并加速了翅膀细胞的 DNA 复制和细胞增殖，从而使原本注定发育成短翅的 BPH 转向长翅形态。此外，NlInR2 的适当表达对于维持翅膀中对称的脉纹模式是必要的。我们的发现为昆虫中两个 InR 旁系同源物的调控复杂性提供了第一个直接证据，暗示了在无脊椎动物中多个 InR 的功能独立进化。
