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

作者：Xu, Wen-Teng; Wang, Xian-Wei; Zhang, Xiao-Wen; Zhao, Xiao-Fan; Yu, Xiao-Qiang; Wang, Jin-Xing^*

来源：Amino Acids, 2010, 39(5): 1227-1239.

DOI：10.1007/s00726-010-0558-7

• MOLECULAR-CLONING
• MANDUCA-SEXTA
• TOBACCO HORNWORM
• LITOPENAEUS-VANNAMEI
• BINDING-PROTEIN
• IMMUNE-SYSTEM
• BOMBYX-MORI
• LIPOPOLYSACCHARIDE
• RECOGNITION
• IMMULECTIN-2

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 (FcLec5) 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 FcLec5 mRNA was specifically expressed in hepatopancreas. FcLec5 protein was expressed in hepatopancreas and secreted into hemolymph. Real-time PCR showed that FcLec5 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 Ca2+-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 Ca2+-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.

• 出版日期2010-11
• 单位山东大学