关键词: 中华按蚊, 血餐, 血红素加氧酶-1, 血红素, 表达谱

Abstract: 【Aim】 A blood meal is essential for the anautogenous mosquito to complete each gonotrophic cycle. The hydrolysis of blood proteins by midgut proteases results in a massive release of free heme, a known prooxidant molecule. The blood-sucking mosquitoes must strictly regulate heme homeostasis. An important component of this control is heme oxygenase (HO). The existing research results show that the heme-degradation pathway is likely to be different in different insect orders. Our study aims to clone HO-1 gene from  Anopheles sinensis, analyze its expression post blood feeding to provide the foundation for further research of the molecular mechanism of heme homeostasis in An. sinensis. 【Methods】 A transcriptome database for An. sinensis was mined through bioinformatic analysis. Gene expression levels were analyzed in the midgut and other body tissues except midgut (carcass) and at different time post blood feeding using real-time PCR. Meanwhile, the concentrations of heme at different time post blood feeding were measured. 【Results】A HO-1 gene was identified, and named as AsHO-1, with the GenBank accession number of KP994552. AsHO-1 contains a 729 bp open reading frame encoding 242 amino acid residues. Expression analysis showed that AsHO-1 was simultaneously expressed in the midgut and carcass of An. sinensis and the expression level of AsHO-1 in carcass was markedly higher than that in the midgut. AsHO-1 mRNA levels remained elevated at 6-12 h after glucose feeding with a maximum 4.2fold increase, while the expression level significantly increased at 12-24 h post blood feeding with a maximum 11.67-fold increase. The heme level increased significantly at 3 h post blood feeding, peaked at 6 h, and then decreased at 18 h. 【Conclusion】 These findings suggest that AsHO-1 can be induced by blood feeding, and may be involved in the regulation of heme homeostasis, although further researches need to be performed to confirm this speculation. Furthermore, AsHO-1 is also highly expressed at larval stage and in body tissues except midgut, suggesting that AsHO-1 might be involved in multiple physiological processes of An. sinensis.

Key words: Anopheles sinensis , blood meal, heme oxygenase-1, heme, expression profile