Fig. 3. Formation of the chromatoid body at stage I. (A) Phase contrast microscopy of early chromatoid bodies. Squash preparations at specific stages (indicated in the lower right corner of each picture) were observed by phase contrast microscopy. Stage I was divided into three subgroups (Ia, Ib and Ic) on the basis of the progress of the chromatoid body compaction. In step Ia spermatids, chromatoid body material is still dispersed in the cytoplasm. In step Ib, chromatoid bodies start condensing and, in step Ic, they are finally condensed to the final form corresponding to the mature chromatoid bodies seen also at later stages. Arrows point to chromatoid bodies; asterisks show the location of the developing acrosome. (B) Localization of MVH in the forming chromatoid bodies. Immunostaining of squash preparations at specific stages was performed using polyclonal anti-MVH antibody (-MVH) and Alexa Fluor 594 anti-rabbit IgG as a secondary antibody (red). Nuclei are stained blue with DAPI. Bars, 5 µm.