›› 2017, Vol. 60 ›› Issue (6): 621-631.doi: 10.16380/j.kcxb.2017.06.002

• RESEARCH PAPERS • Previous Articles     Next Articles

Molecular characterization and blood feeding-relative expression analysis of eight carboxypeptidase genes in Anopheles sinensis (Diptera: Culicidae) (In English)

SHI Zong-Pan, ZHI Zhong-Jing, LUO Shi-Hui, CHEN Bin, HE Zheng-Bo*   

  1. (Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, Chongqing Normal University, Chongqing 400047, China)
  • Online:2017-06-20 Published:2017-06-20

Abstract: 【Aim】 The objective of this study is to characterize eight digestive carboxypeptidase genes in Anopheles sinensis, and to analyze their expression patterns before and post blood meal feeding. 【Methods】 The characteristics of eight digestive carboxypeptidase genes of An. sinensis were analyzed using bioinformatics methods, and their expression levels in different tissues at different developmental stages and in the midguts of female adults at different time points post blood meal feeding (PBM) were compared by semi-quantitative reverse transcription PCR and quantitative realtime PCR (qRT-PCR), respectively. 【Results】 Bioinformatics analysis indicated that of the eight carboxypeptidase genes, six genes encode carboxypeptidases A (AsCPA-I-AsCPA-VI) and two encode carboxypeptidases B (AsCPB-I and AsCPB-II). The expression of AsCPA-V was only detected in midguts and carcasses (whole mosquitoes minus midgut) of the 4th instar larvae, suggesting that it might have specific expression in larvae, while the other seven genes were simultaneously expressed in the 4th instar larvae and adults. After blood meal feeding, the expression levels of AsCPA-I, AsCPA-II, AsCPA-III, AsCPA-IV, AsCPA-VI, AsCPB-I and AsCPB-II in the midguts of female adults significantly changed, but their expression patterns were completely different, suggesting that the blood protein digestion is a complex process involving the coordinative expressions of multiple genes. The expression levels of AsCPA-I, AsCPA-III, AsCPA-IV, AsCPA-VI and AsCPB-II were all up-regulated and peaked at 24 h PBM. Especially, the expression level of AsCPA-VI rapidly increased at 3 h PBM, and peaked at 24 h PBM with~418fold induction, and that of AsCPB-II also increased by more than 40-fold at 24 h PBM, suggesting that they might be involved in blood protein digestion. However, the expression levels of AsCPA-II and AsCPB-I in midguts of female adults were significantly down-regulated after blood meal feeding. 【Conclusion】 Eight carboxypeptidase genes from An. sinensis were characterized. Among them, AsCPA-I, AsCPA-III, AsCPA-IV, AsCPA-VI and AsCPB-II are putatively involved in blood protein digestion; in particular, AsCPA-VI and AsCPB-II might play more important roles. Our results provide a basis for further study on the molecular mechanism of blood protein digestion in mosquitos as well as in An. sinensis.

Key words: Anopheles sinensis; carboxypeptidase, molecular characterization, expression pattern, blood meal, blood protein digestion