Fig. 2.

A failure of flagella biogenesis in Cfap70-KO spermatids. (a) Spermatids were isolated from testicular cells using flow cytometry after Hoechst 33,342 staining. Representative immunofluorescence staining of acetylated-tubulin (ac-Tub) (red) and PNA-FITC (green) in round spermatids from Cfap70-KO mice and their littermate WT mice. Nu, nucleus; Acr, acrosome; Fla, flagella. Scale bar, 50 μm. (b) As revealed by ac-Tub staining, the percentage of round spermatids with normal flagella formation was analysed in Cfap70-KO mice and their littermate WT mice. Data were presented as the mean ± SD (n = 5 each group). At least 50 round spermatids were counted for each mouse. Statistical significance was determined by two-tailed, unpaired Student's t test; p < 0.0001. (c) Representative TEM images of testis sections in Cfap70-KO mice and their littermate WT mice. In WT spermatids, a well-organized “9 + 2” axoneme could be easily observed and the midpiece of the flagella was surrounded by the mitochondrial sheath (MS). However, assembled axoneme structures were rarely observed in Cfap70-KO spermatids, and mitochondria (Mt) were scattered. If observed, the axoneme was also severely disorganized. The lower panel (a’-f’) was the enlarged images. Nu, nuclei. Scale bar, 1 μm. (d) As revealed by TEM, the percentage of spermatids with assembled axonemes was analysed in the testes of Cfap70-KO mice and their littermate WT mice. Data were presented as the mean ± SD (n = 3 each group). At least 30 spermatids were counted for each mouse. Statistical significance was determined by two-tailed, unpaired Student's t test; p = 0.0002.