Figure 6
Localization of profilin 3 (panels 1) and profilin 4 (panels 2) during rat spermiogenesis. 1, panels A-C: S9 spermatids display profilin 3 immunoreactivity (A) in acroplaxome (F-actin component stained with phalloidin-Texas Red) and manchette (detected with tubulin monoclonal antibody). Manchette is caudal to acroplaxome (B). Arrows in B and C indicate tubulin immunoreactive spermatid tail. Arrowhead in C (Pha-Co microscopy: phase-contrast microscopy) points to acrosomal granule. Apx: acroplaxome. Man: manchette. Panels D-F: S10 spermatid. Profilin 3 is predominant in manchette. Panels G-I: S14 spermatid. Profilin 3 extends into cytoplasm caudal to manchette. Panels J-L: S14 spermatid. Panel K illustrates position of acroplaxome. Note that profilin 3 is not associated with the acroplaxome but with the manchette. 2, panels A-C. Early S8 (eS8). Profilin 4 is predominant in acroplaxome (A) at the initiation of the manchette (B). C indicates positions of acroplaxome (Apx) and manchette (Man). Panels D-F. S14 spermatid. Profilin 4 is seen in manchette but not in acroplaxome. Panels G-I. S9 spermatid. Profilin 4 is predominant in manchette (G). Position of acroplaxome is shown in H. Note that adjacent Golgi is slightly stained. I indicates acroplaxome (Apx), manchette (Man) and Golgi resolved by phase-contrast. Panels J-L. S14 spermatid. Profilin 4 is restricted to manchette (J) and not seen in acroplaxome (seen in K). L indicates manchette (Man) and acroplaxome (Apx). Panel M provides diagrammatic summary (not to scale) of profilin 3 and profilin 4 localization sites during S6 to S10. The acroplaxome is immunoreactive in S6 spermatids. Acrosomal immunoreactivity decreases in apical region in S7 spermatids preceding the onset of manchette assembly (S8). Profilin 3 and profilin 4 are predominant in the manchette of S9 and S10 spermatids. Note migration of Golgi from apical to caudal position in spermatid cytoplasm. Scale bars: 2 μm.