title: Mutation of a cuticular protein, BmorCPR2, alters larval body shape and adaptability in silkworm, Bombyx mori.
abstract: Cuticular proteins (CPs) are crucial components of the insect cuticle. Although numerous genes encoding cuticular proteins have been identified in known insect genomes to date, their functions in maintaining insect body shape and adaptability remain largely unknown. In the current study, positional cloning led to the identification of a gene encoding an RR1-type cuticular protein, BmorCPR2, highly expressed in larval chitin-rich tissues and at the mulberry leaf-eating stages, which is responsible for the silkworm stony mutant. In the Dazao-stony strain, the BmorCPR2 allele is a deletion mutation with significantly lower expression, compared to the wild-type Dazao strain. Dysfunctional BmorCPR2 in the stony mutant lost chitin binding ability, leading to reduced chitin content in larval cuticle, limitation of cuticle extension, abatement of cuticle tensile properties, and aberrant ratio between internodes and intersegmental folds. These variations induce a significant decrease in cuticle capacity to hold the growing internal organs in the larval development process, resulting in whole-body stiffness, tightness, and hardness, bulging intersegmental folds, and serious defects in larval adaptability. To our knowledge, this is the first study to report the corresponding phenotype of stony in insects caused by mutation of RR1-type cuticular protein. Our findings collectively shed light on the specific role of cuticular proteins in maintaining normal larval body shape and will aid in the development of pest control strategies for the management of Lepidoptera.
authors: State Key Laboratory of Silkworm Genome Biology, Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, 400715, China.
authors: Liang
authors: L
authors: Qiao
authors: Gao
authors: G
authors: Xiong
authors: Ri-xin
authors: RX
authors: Wang
authors: Song-zhen
authors: SZ
authors: He
authors: Jie
authors: J
authors: Chen
authors: Xiao-ling
authors: XL
authors: Tong
authors: Hai
authors: H
authors: Hu
authors: Chun-lin
authors: CL
authors: Li
authors: Ting-ting
authors: TT
authors: Gai
authors: Ya-qun
authors: YQ
authors: Xin
authors: Xiao-fan
authors: XF
authors: Liu
authors: Bin
authors: B
authors: Chen
authors: Zhong-huai
authors: ZH
authors: Xiang
authors: Cheng
authors: C
authors: Lu
authors: Fang-yin
authors: FY
authors: Dai
mesh_terms: D000220:Adaptation, Biological; D000818:Animals; D012831:Bombyx / Q000033:anatomy & histology* / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D002686:Chitin / Q000378:metabolism*; D003001:Cloning, Molecular; D056426:Genetic Loci; D049750:Genome, Insect; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism*; D007814:Larva / Q000033:anatomy & histology / Q000235:genetics; D009154:Mutation; D009928:Organ Specificity; D010641:Phenotype
chemical_list: D019476:Insect Proteins; D002686:Chitin
keywords: Bombyx mori; RR1-type cuticular protein; cuticle physical properties; larval morphological characteristics and adaptability; stony mutant