Sperm from four different gene-disrupted mouse lines (calmegin [Clgn], Adam1a, Adam2, and Ace) are known to have defective zona-binding ability. Moreover, it is also reported that the sperm from all of these mouse lines exhibit another common phenotype of impaired migration into oviduct despite the large number of sperm found in uterus after coitus. On the other hand, the sperm from the Adam3-disrupted mouse line was reported to have defects in binding ability to zona, but were able to move into the oviduct. In order to clarify the difference, we investigated the migration of ADAM3-null sperm into oviduct precisely by visualizing the sperm by using acrosin-green fluorescent protein as a tag. As a result, in contrast to previous observations, it was demonstrated that the Adam3-disrupted sperm were unable to migrate into the oviduct after coitus. It was ultimately shown that, in five out of five different gene-disrupted mouse lines, the phenotype of impaired sperm binding to zona pellucida was accompanied by the loss of ability of sperm to migrate into the oviduct. This indicates a close relationship between the two phenomena, and also that sperm migration into the oviduct is a crucial step for fertilization.

MEXT of Japan