Fig. 7.

SUN4 binds to lamin B3 in mouse spermatids. (A) Confocal microscopy image of an elongating spermatid co-immunolabeled with anti-lamin B3 (green) and anti-SUN4 antibodies (red). DNA was counterstained with Hoechst 33258 (blue). Scale bar: 5 µm. Arrowheads indicate the implantation fossa. (B) Immunoblot (IB) is of co-immunoprecipitation from mouse testicular suspension cells with guinea pig anti-SUN4 NTD antibody and non-specific guinea pig IgG as a negative control. Precipitates (IP) and supernatants containing unbound proteins (SN) were probed with rabbit anti-lamin B3 and anti-SUN4 peptide antibodies. Untreated testis cells served as input control. Loaded cell equivalents: 5% input, 2×10⁶; IP, 4×10⁷; SN, 5×10⁶. Note, the SUN4 immunoblot was reused in Fig. S3 as the same co-IP samples were used to test for SUN4-lamin B1 interaction (Fig. S3). Images in A and B are representative of at least two experimental repeats.