Autor(es): Cheng, Jinzhi; Wang, Yu; Li, Fangzhan; Liu, Jian; Sun, Yu; Wu, Jiahong

Resumo: The studies on sialomes have shown that hematophagous mosquito saliva consists of a lot of pharmacologically active proteins, in which C-type lectins have been identified and regarded as an important component of saliva. The previous studies showed that C-type lectins play crucial roles not only in innate immunity but also in promoting disease transmission in mammals. However, the function and mechanism of C-type lectins from the mosquito sialome is still elusive.Methods: A putative C-type lectin gene (Aalb_CTL1) was cloned and expressed from Aedes albopictus by RT-PCR. The deduced amino acid sequence was analyzed by bioinformatic methods. The gene expression profiles in different tissues and various blood-fed stages of Ae. albopictus were examined by Real-Time qRT-PCR and the biological functions of the recombined mature Aalb_CTL1 were tested by hemagglutination and sugar inhibitory agglutination assays. Moreover, the capabilities of rAalb_CTL1 against microorganisms were measured by microbial-agglutination assay.Results: The full-length Open reading frame (ORF) of Aalb_CTL1 consisted of 462 bp, encoding 153 amino acid residues. The deduced amino acid sequence contained a putative signal peptide of 19 amino acids. It also contained a CRD domain with a WND (Trp(137)-Asn(138)-Asp-(139)) motif that needed calcium for the hemagglutinating activity and an imperfect EPS (Glu(128)-Pro(129)-Ser(130)) motif that had a predicted ligand binding specificity for mannose. The mRNA level of Aalb_CTL1 was much higher in female mosquito salivary gland than those in fat body and midgut which was down-regulated in salivary gland after blood feeding. The rAalb_CTL1 contained not only hemagglutinating activity and a high affinity with mannose but also agglutinating activity against yeast C. albicans and Gram-positive bacteria S. aureus in Ca2+ dependent manner.Conclusion: Aalb_CTL1 was a mannose-binding C-type lectin and constituted one of the important components in saliva of Ae. albopictus, which could be involved in the defense against yeast and Gram-positive bacteria infection.

Palavras-Chave: C-type lectin; Salivary gland; Ae. albopictus; Prokaryotic expression; Agglutinating activity

Imprenta: Parasites & Vectors, v. 7, n. 337, 2014

Identificador do objeto digital: 10.1186/1756-3305-7-337

Descritores: Aedes aegypti - Genome ; Aedes aegypti - RT-PCR ; Aedes aegypti - Real Time PCR

Data de publicação: 2014

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