Analysis of loss of adhesive function in sperm lacking cyritestin or fertilin beta

We produced mice lacking the sperm surface protein cryitestin (ADAM 3) and found mutant males are infertile. Similar to fertilin beta (ADAM 2) null sp erm (C. Cho ef al., 1998, Science 281, 1857-1859), cyritestin null sperm ar e drastically deficient in adhesion to the egg zona pellucida (0.3% of wild type) and to the egg plasma membrane (9% of wild type). Thus sperm from ma le mice with a gene deletion of either ADAM have a loss of adhesive functio n in at least two steps of fertilization. We found deletion of either ADAM gene resulted in the loss of multiple gene products. This loss of multiple gene products (sperm membrane proteins) appears to result from a novel, dev elopmental mechanism during sperm differentiation. Because the altered sper m protein expression must be responsible for the fertilization defects, our data suggest new models for the molecular basis of the affected steps in f ertilization. (C) 2001 Academic Press.