Abstract: 【Aim】 This study aims to explore the expression profiles of insect cuticle protein (ICP) gene in different larval tissues and developmental stages of Monochamus alternates. 【Methods】 The gene coding for cuticle protein of M. alternatus was cloned by rapid amplification of cDNA ends (RACE) method. Real-time quantitative PCR was used to detect the gene expression profiles. 【Results】 The cloned cuticle protein gene from M. alternatus was named as MoalICP (GenBank accession no. AGX00998.1). The opening reading frame of MoalICP is 408 bp in length, encoding a protein of 135 amino acids with an estimated molecular mass of 14.51 kDa. Multiple sequence alignment indicated that MoalICP shares the highest amino acid sequence identity (79%) with ICP from Apriona germari (AAM66718.1), and 35%-45% identities with ICPs from 19 insects including Nasonia vitripennis (NP_001161297.1), Drosophila mojavensis (XP_002005461.1), and Papilio polytes (BAM18876.1) at the amino acid level. There is a transmembrane segment between the 10th and the 26th amino acid sites in MoalICP. MoalICP gene was expressed in head, body wall, fat body, haemocytes, Malpighian tubules, and midgut body of larvae. The relative expression level of MoalICP gene in pupae and adults was 44% and 161% of that in larvae, respectively. 【Conclusion】 MoalICP has high amino acid sequence identity with ICPs from other insects. The MoalICP gene is expressed widely in M. alternatus larvae, and has the highest expression level in adults. The present study provides reference for further research on functions of MoalICP and epidermis chemistry of M. alternatus.

Key words:  Monochamus alternatus, cuticular protein, gene cloning, real-time quantitative PCR, RACE