title: Cloning and characterization of a mannose binding C-type lectin gene from salivary gland of Aedes albopictus.
abstract: BACKGROUND
  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 (Trp137-Asn138-Asp-139) motif that needed calcium for the hemagglutinating activity and an imperfect EPS (Glu128-Pro129-Ser130) 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.
  
  
  CONCLUSIONS
  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.
authors: Jinzhi
authors: J
authors: Cheng
authors: Yu
authors: Y
authors: Wang
authors: Fangzhan
authors: F
authors: Li
authors: Jian
authors: J
authors: Liu
authors: Yu
authors: Y
authors: Sun
authors: Department of Parasitology, Guiyang Medical College, Guiyang, Guizhou 550004, China. jiahongwu2008@hotmail.com.
authors: Jiahong
authors: J
authors: Wu
mesh_terms: D000330:Aedes / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology*; D037241:Mannose-Binding Lectins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny
chemical_list: D037241:Mannose-Binding Lectins