Evidence of glycan mosaicism in the equine oviduct
Year: 2025
Type: article
Abstract: We report a lectin histochemical study of oviductal ampulla and isthmus of thirteen mares euthanised at anestrus (1), estrus (5) 1-day post-ovulation (ov+1) (5) or diestrus (2). Five lectins recognising terminal N-acetylgalactosamine residues all bound to most epithelial cells in the isthmus. However, two isthmus specimens showed negative patches with all 5 lectins (estrus) or with 3 of the 5 (ov+1). In contrast, most cells in the ampulla were negative, but all 5 lectins bound to clusters of epithelial cells throughout the estrus cycle, ranging from small foci (diestrus) to areas up to 200 microns in length or more (estrus and ov+1). No positive clusters were seen in anestrus. Other lectins were used to assess whether terminal glycosylation might differ between clones of epithelial cells in the respective tissue compartments. Lectins binding to subterminal β-galactose generally failed to bind the GalNAc-positive foci in ampulla, while staining elsewhere. Conversely, in the isthmus, they bound only to the focal GalNAc-negative areas, while the rest of the tissue was unstained. Terminal lactosamine (Gal-GlcNAc-) and α2-3-linked sialic acid were present in GalNAc-negative foci in the isthmus but negligible elsewhere. We suggest these patterns result from clonal absence or activation of a GalNAc transferase, most likely the blood group A-related enzyme UDP-GalNAc:Fuc α1-2Gal α1-3GalNAc transferase, with the prior presence of terminal αGalNAc blocking the addition of galactose and 2-3-linked sialic acid during biosynthesis. These glycosylation patterns may influence the adherence of sperm and/or early embryo development in the oviduct.
Authors: C.J.P. Jones, S. Wilsher, J.D. Aplin
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: hybrid
Estimated APC paid: $3,210
OpenAlex ID: W4409452087