Characterization of Multisugar-Binding C-Type Lectin (SpliLec) from a Bacterial-Challenged Cotton Leafworm, Spodoptera littoralis

Abstract

BackgroundVarious proteins that display carbohydrate-binding activity in a Ca2+-dependent manner are classified into the C-type lectin family. They have one or two C-type carbohydrate-recognition domains (CRDs) composed of 110–130 amino acid residues in common. C-type lectins mediate cell adhesion, non-self recognition, and immuno-protection processes in immune responses and thus play significant roles in clearance of invaders, either as cell surface receptors for microbial carbohydrates or as soluble proteins existing in tissue fluids. The lectin of Spodoptera littoralis is still uncharacterized.MethodologyA single orf encoding a deduced polypeptide consisting of an 18-residue signal peptide and a 291-residue mature peptide, termed SpliLec, was isolated from the haemolymph of the cotton leafworm, S. littoralis, after bacterial challenge using RACE-PCR. Sequence analyses of the data revealed that SpliLec consists of two CRDs. Short-form CRD1 and long-form CRD2 are stabilized by two and three highly conserved disulfide bonds, respectively. SpliLec shares homology with some dipteran lectins suggesting possible common ancestor. The purified SpliLec exhibited a 140-kDa molecular mass with a subunit molecular mass of 35 kDa. The hemagglutination assays of the SpliLec confirmed a thermally stable, multisugar-binding C-type lectin that binds different erythrocytes. The purified SpliLec agglutinated microorganisms and exhibited comparable antimicrobial activity against gram (+) and gram (−) bacteria too.ConclusionsOur results suggested an important role of the SpliLec gene in cell adhesion and non-self recognition. It may cooperate with other AMPs in clearance of invaders of Spodoptera littoralis.

Functions of Armigeres subalbatus C-type lectins in innate immunity

“…Mammalian CTLs, such as mannose-binding lectins (MBLs), can opsonize microorganisms and activate the lectin pathway of the complement system (Fujita et al, 2004; Ip et al, 2009; Jack and Turner, 2003), and they are also active against cancer cells (Nakagawa et al, 2003). Insect CTLs, such as those from lepidopteran species, have been shown to participate in both cellular and humoral innate immune responses (Ling and Yu, 2006; Seufi et al, 2012; Tian et al, 2009; Watanabe et al, 2006; Yu and Kanost, 2000, 2003, 2004). In Drosophila and mosquitoes, only a few CTLs have been reported to be involved in innate immunity (Ao et al, 2007; Keebaugh and Schlenke, 2012; Schnitger et al, 2009; Tanji et al, 2006).…”

“…6). Broad binding spectrum is common to invertebrate CTLs, for example, insect and crustacean CTLs containing an EPN motif (mannose-type) have a broad spectrum of agglutinating, opsonizing and microbicidal activities (Seufi et al, 2012; Sun et al, 2008; Tian et al, 2009; Watanabe et al, 2006; Yu et al, 2005, 2006; Zhang et al, 2009). But mammalian CTLs such as mannose-binding lectins (MBLs) have more restricted binding specificity consistent with the predicted binding motif (Drickamer, 1992).…”

Altered Gene Expression: Induction/Suppression in Leek Elicited by Iris Yellow Spot Virus Infection (IYSV) Egyptian Isolate

“…our results confirmed the importance of differential display for discovering and identifying new genes. Several studies (2,41,42) compared RnA microarray and the differential display technique and concluded that DD-PcR is a method that allows systematic comparison of expressed mRnA in the cells. They added that DD-PCR is becoming more efficient today in isolating and characterizing genes differentially expressed among cells, tissues or individuals.…”

Identification of a Novel Secretory Gland Producing C-type Lectin in the Flesh Fly (<i>Sarcophaga peregrina</i>)<i>, </i>and its Characterization

“…CLEM 20 and 36 were shown to be members of C-type lectins (Yamamoto-Kihara & Kotani 2004, Yamamoto-Kihara et al 2011), a group demonstrated to be involved in the self-defense system against pathogenic agents (Natori et al 1999, Yu & Kanost 2003, Tanji et al 2008, Seufi et al 2012. In our preliminary experiments, the extract of CLPT containing the CLEMs was found to be involved in suppression of E. coli growth (our unpublished data).…”