Molecular identification of the sperm selection involved porcine sperm binding glycoprotein (SBG) as deleted in malignant brain tumors 1 (DMBT1).

Porcine sperm binding glycoprotein (SBG) is involved in sperm-oviduct interaction. Here we use mass spectrometry to identify SBG, finding peptides corresponding to deleted in malignant brain tumors 1 (DMBT1), at scavenger receptor cysteine-rich (SRCR) and CUB domains. RT-PCR allowed the cloning of unique sequences, belonging to porcine DMBT1. Western blot and immunofluorescence of oviductal tissues using anti-SBG and anti-hDMBT1 antibodies showed identical results. The biochemical characteristics of both proteins are coincident. We conclude that porcine SBG is an oviductal form of DMBT1, and thus assign this protein a novel location and function.