SL15: a seminal plasma-derived lectin from the sperm of llama ( Lama glama )

ZAMPINI, RENATO; SEQUEIRA, SABRINA; ARGAÑARAZ, MARTIN EDUARDO; APICHELA, SILVANA ANDREA

MOLECULAR REPRODUCTION AND DEVELOPMENT

WILEY-LISS, DIV JOHN WILEY & SONS INC

Año: 2017

1040-452X

The oviductal sperm reservoir of South American camelids is formed when sperm bindto N-acetylgalactosamine (GalNAc) on the surface of oviductal epithelium. The aim ofthis study was to characterize the GalNAc-binding proteins on llama sperm, and toestablish their origin. Sperm-adsorbed proteins were extracted with 0.5 M KCl inHepes-balanced salts. Sperm-adsorbed and seminal plasma proteins were then subjectedto ligand blotting for their GalNAc affinity, and the labeled bands were identified bymass spectrometry. Three proteins were identified in seminal plasma versus only one inthe sperm-adsorbed population; SL15, a seminal lectin, was common to both. SL15 is ahomologue of zymogen granule protein 16, homolog B-like, which belongs to theJacalin-related lectin family. This lectin is likely presented to sperm via seminal plasmasince epididymal sperm are not capable of binding GalNAc, whereas ejaculated spermdoes, and its transcript was enriched predominantly in the prostate and bulbourethralglands. This is the first report of a seminal lectin in South American camelids thatoriginates in the male reproductive tract, and is probably involved in sperm reservoirformation.