A new C-type lectin (FcLec5) from the Chinese white shrimp Fenneropenaeus chinensis

• Published in: Amino acids 2010-11, Vol.39 (5), p.1227-1239
• Main Authors: Xu, Wen-Teng, Wang, Xian-Wei, Zhang, Xiao-Wen, Zhao, Xiao-Fan, Yu, Xiao-Qiang, Wang, Jin-Xing
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Animals; Bacteria; Bacteriology; Base Sequence; Biochemical Engineering; Biochemistry; Biomedical and Life Sciences; DNA, Complementary - genetics; Gram-negative bacteria; Lectins, C-Type - genetics; Lectins, C-Type - immunology; Lectins, C-Type - isolation & purification; Life Sciences; Microbiology; Molecular Sequence Data; Neurobiology; Original Article; Penaeidae - genetics; Penaeidae - microbiology; Phylogeny; Proteomics; Recombinant Proteins - genetics; Recombinant Proteins - immunology; Recombinant Proteins - isolation & purification; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - genetics; RNA, Messenger - immunology; RNA, Messenger - isolation & purification; Sequence Analysis, DNA
• ISSN: 0939-4451; 1438-2199
• DOI: 10.1007/s00726-010-0558-7

C-type lectins are one family of pattern recognition receptors (PRRs) that play important roles in innate immunity. In this work, cDNA and genomic sequences for a new C-type lectin ( FcLec 5) were obtained from the Chinese white shrimp Fenneropenaeus chinensis . FcLec5 cDNA contains an open reading frame of 1,008 bp and its genomic sequence is 1,137 bp with 4 exons and 3 introns. The predicted FcLec5 protein contains a signal peptide and two carbohydrate recognition domains (CRDs). The N-terminal CRD of FcLec5 has a predicted carbohydrate recognition motif of Gln-Pro-Asp (QPD), while the C-terminal CRD contains a motif of Glu-Pro-Gln (EPQ). Northern blot analysis showed that FcLec 5 mRNA was specifically expressed in hepatopancreas. FcLec5 protein was expressed in hepatopancreas and secreted into hemolymph. Real-time PCR showed that FcLec 5 transcript exhibited different expression profiles after immune-challenged with Vibrio anguillarum or White Spot Syndrome Virus (WSSV). Recombinant FcLec5 and its two individual CRDs could agglutinate most bacteria tested, and the agglutinating activity was Ca 2+ -dependent. Besides, the agglutinating activity to gram-negative bacteria is higher than that to gram-positive bacteria. Direct binding assay showed that recombinant FcLec5 could bind to all microorganisms tested (five gram-positive and four gram-negative bacteria, as well as yeast) in a Ca 2+ -independent manner. Recombinant FcLec5 also directly bound to bacterial peptidoglycan, lipopolysaccharide and lipoteichoic acids. These results suggest that FcLec5 may act as a PRR for bacteria via binding to bacterial cell wall polysaccharides in Chinese white shrimp.