Fig. 3.

Tex46 mutant spermatozoa have impaired motility and ZP penetration. A) Percent of motile sperm after capacitation in TYH medium for 10min and 2 h. Tex46 null (KO) epididymal spermatozoa showed a significantly decreased motility. *P < 0.05, **P < 0.005, Student's t test. B) In vitro fertilization assay of Tex46^−/− male mice using different concentrations of spermatozoa. Tex46 null (KO) spermatozoa were unable to fertilize any oocytes, even after concentration was increased from 1 × (2 × 10⁵ sperm/mL) to 3 × (6 × 10⁵ sperm/mL). n = 3. ***P < 0.001, Student's t test. C) In vitro fertilization assay of Tex46^−/− male mice using cumulus-intact, cumulus-free, and ZP-free oocytes. Tex46 null (KO) spermatozoa were unable to fertilize cumulus-intact (with cumulus cells) and cumulus-free (with ZP) oocytes. In contrast, the percentage of oocytes at the two-cell stage was partially rescued with ZP-free (without ZP) eggs. **P < 0.005, ***P < 0.001, Student's t test. D) Population of bent and nonbent sperm heads in the testis and epididymis. The primary defect in Tex46^−/− (KO) mice is sperm head formation in the testis. Sperm head-tail junction bending is the secondary effect of Tex46^−/− mice during the epididymal transition. n = 4 males. ***P < 0.001, Student's t test. E) Observation of the acrosome and flagella using EGFP expressed under the Acrosin promoter (Acr-EGFP) and mitochondria-targeted DsRed2 in the principal piece (Su9-DsRed2) in Tex46 null spermatozoa. Although almost all sperm heads of testicular Tex46 null (KO) spermatozoa are blunted, they nevertheless remain straight like those of WT spermatozoa. Scale bar: 10 μm.