A specific type of insulin-like peptide regulates the conditional growth of a beetle weapon
A specific type of insulin-like peptide regulates the conditional growth of a beetle weapon
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DOI：
10.1371/journal.pbio.3000541
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发表时间：
2019-11-01
期刊：
影响因子：
9.8
通讯作者：
Okada, Kensuke
中科院分区：
文献类型：
--
作者：
Okada, Yasukazu;Katsuki, Masako;Okada, Kensuke
进化上保守的胰岛素/胰岛素样生长因子（IGF）信号转导（IIS）已被确定为动物性选择武器生长的营养依赖性调节的主要生理机制。然而，将营养状态与武器生长结合起来的分子机制在很大程度上仍然未知。在这里，我们表明，一个特定的亚型胰岛素样肽（ILP）响应营养状况，从而调节武器的大小在宽角面粉甲虫Gnatocerus cornutus。利用转录组信息，我们鉴定了5个G。cornutus ILP（GcorILP 1 -5）和2株G.角形葡萄球菌胰岛素样受体（GcorInR 1，-2）基因在G. cornutus基因组RNA干扰（RNAi）介导的基因沉默揭示了ILP的一种亚型GcorILP 2特异性地调节武器大小。重要的是，GcorILP 2以条件依赖性方式在脂肪体中高度特异性表达。我们进一步发现GcorInR 1和GcorInR 2在功能上是冗余的，但后者部分专门用于调节武器生长。这些结果有力地表明，GcorILP 2是一个重要的组成部分的发育机制，耦合营养状态的武器生长在G。角状的我们认为，IIS基因的重复和随后的多样化在第二性征复杂的生长调节的进化中发挥了关键作用。
Evolutionarily conserved insulin/insulin-like growth factor (IGF) signaling (IIS) has been identified as a major physiological mechanism underlying the nutrient-dependent regulation of sexually selected weapon growth in animals. However, the molecular mechanisms that couple nutritional state with weapon growth remain largely unknown. Here, we show that one specific subtype of insulin-like peptide (ILP) responds to nutrient status and thereby regulates weapon size in the broad-horned flour beetle Gnatocerus cornutus. By using transcriptome information, we identified five G. cornutus ILP (GcorILP1-5) and two G. cornutus insulin-like receptor (GcorInR1, -2) genes in the G. cornutus genome. RNA interference (RNAi)-mediated gene silencing revealed that a certain subtype of ILP, GcorILP2, specifically regulated weapon size. Importantly, GcorILP2 was highly and specifically expressed in the fat body in a condition-dependent manner. We further found that GcorInR1 and GcorInR2 are functionally redundant but that the latter is partially specialized for regulating weapon growth. These results strongly suggest that GcorILP2 is an important component of the developmental mechanism that couples nutritional state to weapon growth in G. cornutus. We propose that the duplication and subsequent diversification of IIS genes played a pivotal role in the evolution of the complex growth regulation of secondary sexual traits.