Yang Cong-Hui, Yang Peng-Cheng, Zhang Su-Fang, Shi Zhi-Yong, Kang Le, Zhang Ai-Bing
College of Life Sciences, Capital Normal University, Beijing, 100048, China.
Beijing Institutes of Life Science, Chinese Academy of Sciences, Beijing, 100101, China.
Insect Biochem Mol Biol. 2017 Apr;83:94-106. doi: 10.1016/j.ibmb.2017.03.003. Epub 2017 Mar 9.
Cuticular proteins (CPs) are vital components of the insects' cuticle that support movement and protect insect from adverse environmental conditions. The CPs exist in a large number and diversiform structures, thus, the accurate annotation is the first step to interpreting their roles in insect growth. The rapid development of sequencing technology has simplified the access to the information on protein sequences, especially for non-model species. Dendrolimus punctatus is a Lepidopteran defoliator, and its periodic outbreaks cause severe damage to the coniferous forests. The transcriptome of D. punctatus integrating the whole developmental periods are available for the potential investigation of CPs. In this study, we identified 216 CPs from D. punctatus, including 147 from CPR family, 4 from TWDL family, 3 from CPF/CPFL families, 22 from CPAP families, 8 low complexity proteins, 1 CPCPC and 31 from other CP families. The putative CPs were compared with homologs in other species such as Bombyx mori, Manduca sexta and Drosophila melanogaster. We further identified five co-orthologous groups have highly similar sequences of CRPs in nine lepidopteran species, which exclusively presented in RR-2 subfamily rather than RR-1. We inferred that in Lepidoptera the difference in RR-2 numbers was maintained by homologs in co-orthologous groups, coincided with observation in Drosophila and Anopheles that gene cluster was the model and source for the expansion of RR-2 genes. In combination with the variation of members in each CP family among different species, these results indicated the evolution of CPs was highly correlated to the adaptation of insect to environment. Furthermore, we compared the amino acid composition of the different types CPRs, and examined the expression patterns of CP genes in various developmental stages. The comprehensive overview of CPs from our study provides an insight into their evolution and the association between them and insect development.
表皮蛋白（CPs）是昆虫表皮的重要组成部分，支撑昆虫运动并保护其免受不利环境条件的影响。CPs数量众多且结构多样，因此，准确注释是解读其在昆虫生长中作用的第一步。测序技术的快速发展简化了获取蛋白质序列信息的过程，尤其是对于非模式物种。马尾松毛虫是一种鳞翅目食叶害虫，其周期性爆发对针叶林造成严重破坏。整合了整个发育阶段的马尾松毛虫转录组可用于对CPs进行潜在研究。在本研究中，我们从马尾松毛虫中鉴定出216种CPs，包括147种来自CPR家族、4种来自TWDL家族、3种来自CPF/CPFL家族、22种来自CPAP家族、8种低复杂性蛋白、1种CPCPC以及31种来自其他CP家族。将推定的CPs与家蚕、烟草天蛾和黑腹果蝇等其他物种的同源物进行了比较。我们进一步鉴定出五个直系同源组在九种鳞翅目物种中具有高度相似的CRPs序列，这些序列仅出现在RR-2亚家族而非RR-1中。我们推断，在鳞翅目中，RR-2数量的差异由直系同源组中的同源物维持，这与在果蝇和按蚊中的观察结果一致，即基因簇是RR-2基因扩增的模式和来源。结合不同物种中每个CP家族成员的变异，这些结果表明CPs的进化与昆虫对环境的适应性高度相关。此外，我们比较了不同类型CPRs的氨基酸组成，并研究了CP基因在各个发育阶段的表达模式。我们研究中对CPs的全面概述为深入了解其进化以及它们与昆虫发育之间的关联提供了见解。
