Molecular cloning of the human fertilin beta subunit.

Fertilin, a heterodimeric sperm surface protein, first identified in guinea pig, has been shown to play an important role in sperm-egg interactions. We report here the complementary DNA and deduced amino acid sequence of human fertilin beta. The human fertilin beta shares significant sequence homology with mouse, guinea pig and monkey fertilin beta and also exhibits similar structural organization. Of particular interest, the mature guinea pig fertilin beta contains an amino-terminal 90 amino acid disintegrin domain. It has been suggested that the integrin recognition sequence (TDE) of the guinea pig fertilin beta disintegrin domain mediates sperm-egg binding. The amino acid sequence at this position in human fertilin beta differs from the mouse, guinea pig and monkey sequence (mouse-QDE; human-FEE; monkey-FDE).