Fig. 3

The variant of SSFA2 is pathogenic and induced decreased protein expression of SSFA2. A The expression of SSFA2 in sperm was detected in healthy controls and the patient by immunofluorescence (green, SSFA2; red, PNA; blue, DAPI; scale bars, 1 μm). B Western blot analysis showed that SSFA2 could hardly be detected in the sperm lysates compared with the healthy control. C Three-dimensional structural model of SSFA2. The close-up views of the structural superposition of SSFA2-WT (white) and the corresponding variant R1224Q (orange) are displayed with a transparent new cartoon representation. The R1224 (white) and Q1224 (orange) residues are shown with Licorice representation. The change in the Gibbs free-energy gap (ddG) and the stability upon mutation are also indicated. D Wild-type and mutant plasmids of SSFA2 were constructed, and protein expression was detected in HEK-293 T cells