A single-CRD C-type lectin is important for bacterial clearance in the silkworm. (December 2016)

• Record Type: Journal Article
• Authors: Zhan, Ming-Yue; Shahzad, Toufeeq; Yang, Pei-Jin; Liu, Su; Yu, Xiao-Qiang; Rao, Xiang-Jun
• Is Part Of: Developmental and comparative immunology. Volume 65(2016)
• Page Start: 330
• Page End: 339
• Publication Date: 2016-12
• Subjects: Insect immunity -- Silkworm -- C-type lectin; Immunology -- Periodicals; Developmental immunology -- Periodicals; 616.079
• DOI: 10.1016/j.dci.2016.08.004
• Languages: English
• ISSNs: 0145-305X

Abstract

Abstract: C-type lectins (CTLs) depend on the carbohydrate-recognition domain (CRD) to recognize carbohydrates by a Ca 2+ -dependent mechanism. In animals, CTLs play critical roles in pathogen recognition, activation of the complement system and signaling pathways. Immulectins (Dual-CRD CTLs) in lepidopteran are involved in recognizing pathogens. However, little is known about the immune-related functions of insect single-CRD CTLs. Here, we reported the characterization of C-type lectin-S3 ( CTL-S3 ), a single-CRD CTL from the domesticated silkmoth Bombyx mori (Lepidoptera: Bombycidae). The ORF of CTL-S3 gene is 672 bp, which encodes a putative protein of 223 amino acids. CTL-S3 gene was expressed in a variety of tissues. Levels of CTL-S3 mRNA in fertilized eggs and whole larvae were elevated upon bacterial challenges. CTL-S3 was secreted to larval hemolymph. The recombinant protein (rCTL-S3) binds to bacterial cell wall components and bacteria. CTL-S3 inhibited the growth of Bacillus subtilis and caused agglutination of Staphylococcus aureus . More importantly, CTL-S3 facilitated the rapid clearance of Escherichia coli and Staphylococcus aureus from the body cavity of larvae. Taken together, our results suggested that CTL-S3 may function as an opsonin in larval hemolymph to enhance the clearance of pathogens. Highlights: We identified and characterized a C-type lectin (CTL-S3) in Bombyx mori. BmCTL-S3 was significantly upregulated in fertilized eggs and whole larvae after bacterial challenges. BmCTL-S3 could bind to bacteria and bacterial cell wall components. BmCTL-S3 facilitated the clearance of bacteria from hemolymph.