About the Cover

About the Cover
Progression of chromosome synapsis, stabilization of homologous pairing, and changes in chromosome organization throughout prophase of meiosis I are depicted for nuclei of whole-mount gonads from Caenorhabditis elegans hermaphrodites. Background: DAPI-stained germlines of wild-type, syp-3(ok758), and syp-3(me42) mutants (top, middle, and bottom, respectively) where syp-3 encodes for a new structural component of the synaptonemal complex (SC). Insets: High-magnification images of nuclei with DAPI-stained chromosomes (blue), either immunostained to visualize the SC (green) or hybridized with fluorescence in situ hybridization probes (red and green) to assess chromosome pairing. Insets are positioned at the stages where these nuclei are observed (transition zone, left; pachytene, right). Both chromosome synapsis and pairing are impaired in syp-3 mutants revealing that SYP-3 restricts SC assembly to bridge paired chromosome axes, thereby stabilizing homologous pairing. See SMOLIKOV et al. companion articles (pp. 2015–2025 and 2027–2033).