Application of a lectin from the mushroom Polysporus squamosus for the histochemical detection of the NeuAcα2,6Galβ1,4Glc/GlcNAc sequence of N-linked oligosaccharides: a comparison with the Sambucus nigra lectin

Abstract

The lectin from the mushroom Polysporus squamosus (PSL) has an extended carbohydrate combining site, which exhibits a high specificity and affinity toward the NeuAc5α2,6Galβ1,4Glc/GlcNAc trisaccharide sequence of asparagine-linked oligosaccharides. Therefore, PSL should be a superior reagent to the lectin from Sambucus nigra (SNA), which does not discriminate between α2,6-linked NeuAc5 present either in asparagineor serine/threonine-linked oligosaccharides. We have prepared a digoxigenin-conjugated PSL and applied it for histochemistry and blotting. We observed a more restricted staining pattern by PSL as compared to SNA in paraffin sections from different rat organs. Pretreatment of sections with N-glycanase F abolished PSL staining indicating that it interacts only with asparagine-linked oligosaccharides. Furthermore, PSL staining was neuraminidase sensitive. In contrast, SNA staining was only partially sensitive to N-glycanase F pretreatment demonstrating that it was in part due to α2,6-linked NeuAc5 present in serine/threonine-linked oligosaccharides. The most striking observation in this regard was that PSL, in contrast to SNA, did not stain the mucus of sheep submandibular gland, which is extremely rich in serine/threonine-linked Neu5Acα2,6N-acetylgalactosamine. Furthermore, in some tissues neuraminidase pretreatment resulted in increased intensity of SNA staining probably due to binding to exposed terminal N-acetylgalactosamine residues. Collectively, these results indicate that PSL is a useful tool for the histochemical detection of α2,6-linked NeuAc5 in asparagine-linked oligosaccharides.Keywords Polysporus squamosus lectin · Sambucus nigra agglutinin · N-glycans · Histochemistry Roth et al. 1984Roth et al. , 1985Schulte et al. 1984;Taatjes and Roth 1991). Since sialic acids occur in specific glycosidic linkages to the penultimate sugar at the non-reducing terminus of oligosaccharide side chains, an important advance for the field was accomplished with the isolation and characterization of lectins with high specificity for sialic acids present in a particular glycosidic linkage. The first reported linkage-specific lectin was the one isolated from Elderberry bark, the Sambucus nigra L. lectin (SNA), recognizing N-acetylneuraminic Application of a lectin from the mushroom Polysporus squamosus for the histochemical detection of the NeuAcα2,6Galβ1,4Glc/GlcNAc sequence of N-linked oligosaccharides: a comparison with the Sambucus nigra lectin

Lectins: Getting Familiar with Translators of the Sugar Code

“…This lectin is specific for the α2,6-sialyl branch end of N-glycans [ 69 , 70 , 71 ]. Sialylation can entirely change the bioprofile of a glycan branch, by reducing intermolecular interactions through charge repulsion passively or by switching off/on ligand avidity for lectins (such as galectins or siglecs) actively.…”

Sialosignaling: Sialyltransferases as engines of self-fueling loops in cancer progression

“…2), mediated by β-galactoside α2,6-sialyltransferase (ST6GAL1) generates α2,6-sialylated lactosamine (Sia6LacNAc). Lectins from Sambucus nigra (SNA), Trichosanthes japonica [112] or Polysporus squamosus [113] have been widely used to detect Sia6LacNAc in normal and cancer tissues. The fucosylated variant of Sia6LacNAc recognized by antibody ST2H [114] and the CDw75 antigen [115] are also the product of ST6GAL1.…”

Cloning, expression in Escherichia coli and characterization of the recombinant Neu5Acα2,6Galβ1,4GlcNAc-specific high-affinity lectin and its mutants from the mushroom Polyporus squamosus

“…In a further study, PSL was compared with SNA in the histochemical detection of the Neu5Acα2,6Galβ1,4GlcNAc sequence of N-linked oligosaccharides [4]. A more restricted staining pattern was observed by PSL compared with SNA in paraffin sections from different rat organs.…”