Establishment, characterization, and application of pAcr-SP-NTP-EGFP transgenic mice in visualizing the oviduct-migrating ability of sperm from Prss37-null mice.

Transgenic mouse model with fluorescently labeled sperm has extensive application value. It is an auxiliary tool for investigating the mechanism of fertilization, especially for visualizing the oviduct-migrating ability of sperm in vivo. Here, we produced transgenic mouse lines whose sperm were tagged with enhanced green fluorescent protein (EGFP) according to the previously described method. Polymerase chain reaction analysis of tail-tip genomic DNA identified 13 founders, of which 5 male founders produced offspring to form transgenic lines. We showed that EGFP was testis-specifically expressed, sharing similar expression pattern with endogenous acrosin. It has luminal side restricted distribution in seminiferous tubules and acrosomal aggregation in mature sperm. In addition, interstrain hybridization obtained Prss37(-/-)EGFP(tg/+) males produced sperm with impaired oviduct-migrating ability as visualized under fluorescence microscope, compared with Prss37(+/+)EGFP(tg/+) counterparts. These results indicate that a transgenic mouse model with fluorescently labeled sperm has been successfully established and it is a useful tool for evaluating the oviduct-migrating ability of sperm.