title: Two chitinase 5 genes from Locusta migratoria: molecular characteristics and functional differentiation.
abstract: The duplication of chitinase 5 (Cht5) into two to five different genes has been reported only in mosquito species to date. Here, we report the duplication of Cht5 genes (LmCht5-1 and LmCht5-2) in the migratory locust (Locusta migratoria). Both LmCht5-1 (505 aa) and LmCht5-2 (492 aa) possess a signal peptide and a catalytic domain with four conserved motifs, but only LmCht5-1 contains a chitin-binding domain. Structural and phylogenetic analyses suggest that LmCht5-1 is orthologous to other insect Cht5 genes, whereas LmCht5-2 might be newly duplicated. Both LmCht5 genes were expressed in all tested tissues with LmCht5-1 highly expressed in hindgut and LmCht5-2 highly expressed in integument, foregut, hindgut and fat bodies. From the fourth-instar nymphs to the adults, LmCht5-1 and LmCht5-2 showed similar developmental expression patterns with transcript peaks prior to each nymphal molting, suggesting that their expression levels are similarly regulated. Treatment with 20-hydroxyecdysone (20E; the most active molting hormone) and reducing expression of EcR (ecdysone receptor gene) by RNAi increased and decreased expression of both LmCht5 genes, respectively, indicating that both genes are responsive to 20E. Although transcript level of LmCht5-2 is generally 10-fold higher than that of LmCht5-1, RNAi-mediated suppression of LmCht5-1 transcript led to severe molting defects and lethality, but such effects were not seen with RNAi of LmCht5-2, suggesting that the newly duplicated LmCht5-2 is not essential for development and survivorship of the locust.
authors.affiliation: Research Institute of Applied Biology, Shanxi University, Taiyuan, Shanxi 030006, China.
authors.forename: Daqi
authors.initials: D
authors.lastname: Li
authors.affiliation: Research Institute of Applied Biology, Shanxi University, Taiyuan, Shanxi 030006, China.
authors.forename: Jianqin
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Research Institute of Applied Biology, Shanxi University, Taiyuan, Shanxi 030006, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Research Institute of Applied Biology, Shanxi University, Taiyuan, Shanxi 030006, China.
authors.forename: Xiaojian
authors.initials: X
authors.lastname: Liu
authors.affiliation: Research Institute of Applied Biology, Shanxi University, Taiyuan, Shanxi 030006, China.
authors.forename: Enbo
authors.initials: E
authors.lastname: Ma
authors.affiliation: Research Institute of Applied Biology, Shanxi University, Taiyuan, Shanxi 030006, China; Biotechnology Research Center, Shanxi Academy of Agricultural Sciences, Taiyuan, Shanxi 030031, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
authors.forename: Sheng
authors.initials: S
authors.lastname: Li
authors.affiliation: Department of Entomology, 123 Waters Hall, Kansas State University, Manhattan, KS 66506, USA.
authors.forename: Kun Yan
authors.initials: KY
authors.lastname: Zhu
authors.affiliation: Research Institute of Applied Biology, Shanxi University, Taiyuan, Shanxi 030006, China. Electronic address: zjz@sxu.edu.cn.
authors.forename: Jianzhen
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002688:Chitinases / Q000737:chemistry / Q000235:genetics*; D004440:Ecdysone; D004441:Ecdysterone / Q000494:pharmacology; D018507:Gene Expression Regulation, Developmental; D048188:Locusta migratoria / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D008969:Molecular Sequence Data; D018978:Molting; D005810:Multigene Family; D009758:Nymph / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D010802:Phylogeny; D034622:RNA Interference; D011987:Receptors, Steroid / Q000235:genetics
chemical_list: D011987:Receptors, Steroid; C055469:ecdysone receptor; D004440:Ecdysone; D004441:Ecdysterone; D002688:Chitinases
keywords: 20E regulation; Chitinase 5; Gene duplication; Locust migratoria; RNA interference