Live-cell imaging visualizes dynamics of meiosis and spermatid differentiation.

(A) A diagram showing the spermatid differentiation process in C. elegans. (B) Time-lapse analysis of meiosis and differentiation in 2 connected secondary spermatocytes dissected from him-5 males. White arrow indicates the pseudo-cleavage furrow between 2 undifferentiated spermatids. Double-headed arrow indicates RB expansion during spermatid differentiation. Yellow arrows point to cleavage furrows between spermatids and RB. Dashed line boxes indicate 1 haploid spermatid at each differentiation step. Numbers of released spermatids/total spermatids were quantified and are shown in the top right corner. (C–F) Time-lapse analysis of meiosis and differentiation in 2 connected secondary spermatocytes dissected from him-5 males. Spermatocytes in (C) and (E) are from animals expressing Histone::GFP and RPL-5::GFP, respectively. Spermatocytes in (D) and (F) are stained by MitoTracker Red and SiR-actin, respectively. White arrow in (C) indicates the pseudo-cleavage furrow. In (F), white lines indicate the distribution and enrichment of SiR-actin signal during RB formation. The inset and white arrow show an enlarged view of a moving SiR-actin punctum with a magnification of 4×, and yellow arrows indicate the closure of SiR-actin at the scission site. Scale bars: 5 μm. GFP, green fluorescent protein; RB, residual body; RPL-5, ribosomal protein 5, large subunit; SiR, silicon-rhodamine.