Two chitinase 5 genes from Locusta migratoria: Molecular characteristics and functional differentiation
Two chitinase 5 genes from Locusta migratoria: Molecular characteristics and functional differentiation
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飞蝗的两个几丁质酶 5 基因：分子特征和功能分化
DOI：
10.1016/j.ibmb.2015.01.004
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发表时间：
2015-03-01
影响因子：
3.8
通讯作者：
Zhang, Jianzhen
中科院分区：
文献类型：
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作者：
Li, Daqi;Zhang, Jianqin;Zhang, Jianzhen
几丁质酶5（Cht 5）复制成2至5个不同的基因已被报道，只有在蚊子物种。在这里，我们报告的Cht 5基因（LmCht 5 -1和LmCht 5 -2）在飞蝗（Locusta migratoria）的重复。LmCht 5 -1（505 aa）和LmCht 5 -2（492 aa）均含有信号肽和催化结构域，但只有LmCht 5 -1含有几丁质结合结构域。结构和系统发育分析表明，LmCht 5 -1与其它昆虫Cht 5基因是同源的，而LmCht 5 -2可能是新复制的。两个LmCht 5基因在所有测试的组织中表达，其中LmCht 5 -1在后肠中高度表达，LmCht 5 -2在珠被、前肠、后肠和脂肪体中高度表达。从四龄若虫到成虫，LmCht 5 -1和LmCht 5 -2的发育表达模式相似，在每次若虫蜕皮前都有转录高峰，表明它们的表达水平受到相似的调控。用20-羟基蜕皮激素（20 E;最活跃的蜕皮激素）处理和通过RNAi减少EcR（蜕皮激素受体基因）的表达分别增加和减少两种LmCht 5基因的表达，表明两种基因都对20 E有反应。虽然LmCht 5 -2的转录水平通常比LmCht 5 -1高10倍，但RNAi介导的LmCht 5 - 1转录抑制导致严重的蜕皮缺陷和死亡，但LmCht 5 -2的RNAi没有观察到这种效应，表明新复制的LmCht 5 -2对蝗虫的发育和存活不是必需的。(C)2015爱思唯尔有限公司版权所有。
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. (C) 2015 Elsevier Ltd. All rights reserved.