Molecular cloning and analysis of a C‐type lectin from silkworm Bombyx mori

Abstract

C-type lectins (CTLs) play a variety of roles in plants and animals. They are involved in animal development, pathogen recognition, and the activation of immune responses. CTLs carry one or more non-catalytic carbohydrate-recognition domains (CRDs) to bind specific carbohydrates reversibly. Here, we report the molecular cloning and functional analysis of a single-CRD CTL, named C-type lectin-S2 (BmCTL-S2) from the domesticated silkmoth Bombyx mori (Lepidoptera: Bombycidae). The ORF of CTL-S2 is 666 bp, which encodes a putative protein of 221 amino acids. BmCTL-S2 is expressed in a variety of immune-related tissues, including hemocytes and fat body among others. BmCTL-S2 mRNA level in the midgut and the fat body was significantly increased by bacterial challenges. The recombinant protein (rBmCTL-S2) bound different bacterial cell wall components and bacterial cells. rBmCTL-S2 also inhibited the growth of Bacillus subtilis and Staphylococcus aureus. Taken together, we infer that BmCTL-S2 is a pattern-recognition receptor with antibacterial activities.

A C‐type lectin with a single carbohydrate‐recognition domain involved in the innate immune response of Tribolium castaneum

“…BmCTLS2 is mainly expressed in a variety of immune‐related tissues, including fat body and epidermis (Shahzad et al , ). Here, for the first time, we found that TcCTL6 was expressed predominantly in the CNS, followed by the epidermis.…”

“…Moreover, amino acid sequence alignment analysis found that the orthologues possessed high sequence similarity and many common structural features, suggesting that they have similar functions. Further studies revealed that these two representative sister branches, BmCTLS2 and BmCTLS3 , have the same function of binding bacteria, and they inhibit microbial growth in different species (Zhan et al , ; Shahzad et al , ). It has been suggested that the branch where TcCTL6 is located may have a similar agglutination function as the other two sister groups, but it may have distinctive agglutination activity against various target bacteria.…”

“…In Diptera, a galactose‐specific CTL (called DL1) was purified from Drosophila melanogaster pupae and confirmed to bind to Escherichia coli and Erwinia chrysanthemi and agglutinate E. coli instead of E. chrysanthemi (Tanji et al , ). In Lepidoptera, a recent study found that BmCTLS2 from the domesticated silkworm Bombyx mori can bind different bacterial cell wall components and bacterial cells, and BmCTLS2 could also inhibit the growth of Bacillus subtilis and Staphylococcus aureus (Shahzad et al , ). B. mori CTL‐S3 not only inhibits the growth of bacteria but also facilitates the rapid clearance of E. coli and S. aureus from the body cavity of larvae (Zhan et al , ).…”

Cloning and analysis of peptidoglycan recognition protein‐LC and immune deficiency from the diamondback moth, Plutella xylostella

“…Some full‐length and deletion constructs can induce Drosophila AMP genes in S2 cells. The induction levels were generally less than three‐fold, which were significantly lower than the in vivo inductions (Shahzad et al., ; Yang, Zhan, Ye, Yu, & Rao, ). One possible reason is due to the species‐related difference of the protein sequences.…”

“…Feeding of larvae with bacteria can induce changes in mRNA levels of immune‐related genes (Shahzad, Zhan, Yang, Yu, & Rao, ; Zhan et al., ). To analyze if feeding P. xylostella larvae would cause changes in mRNA levels, qPCR was performed for whole worms after 4 or 8 h of feeding.…”