Fig. 4. The SPOCD1–SPIN1 interaction is essential for spermatogenesis.

a, Representative western-blot analyses of n = 3 immunoprecipitations of the mouse wild type and eight SPOCD1 alanine mutations (8 Ala mut) with SPIN1 in HEK 293 T cells. For whole-blot source data, see Supplementary Fig. 1. b, Representative Coomassie gel image of n = 3 co-precipitation experiments with the indicated recombinant proteins. c–e, Representative images of E16.5 gonocytes from n = 3 wild-type (WT) and Spocd1^ΔSPIN1 mice stained for DNA (blue) and SPOCD1 (c), SPIN1 (d) or MIWI2 (e) (green). Scale bars, 2 μm. f, Number of embryos per plug fathered by studs with the indicated genotype mated to wild-type females. Data are mean and s.e.m. from n = 6 wild-type (15 plugs in total) and n = 6 Spocd1^ΔSPIN1 studs (12 plugs). g, Testis weight of adult mice with the indicated genotype. Data are mean and s.e.m. from n = 8 wild-type and n = 8 Spocd1^ΔSPIN1 mice. Inset, a representative image of testes from wild-type (left) and Spocd1^ΔSPIN1 (right) mice. P-values in f and g were determined by unadjusted two-sided Student’s t-test. h, Representative images of PAS and haematoxylin-stained testes sections of wild-type and n = 5 Spocd1^ΔSPIN1 adult mice, with different types of spermatogenic arrest observed in the tubules of the Spocd1^ΔSPIN1 testes indicated. The percentage of each type of tubule is noted alongside. Scale bar, 20 μm. i,j, Adult testis sections stained for the DNA damage marker γH2AX (red) (i) and apoptotic cells (red) by TUNEL assay (j) from wild-type and Spocd1^ΔSPIN1 mice (representative of n = 3 mice per genotype for γH2AX and n = 2 wild-type plus n = 3 Spocd1^ΔSPIN1 mice for TUNEL). DNA was stained with DAPI (blue). Scale bars, 100 μm.