Figure 5. CRA-1 is Required for SC Central Region Formation.

(A–H) High magnification images of nuclei from the transition zone and late pachytene in wild type and cra-1 mutants. DAPI-stained chromosomes are immunostained with anti-HTP-3 to observe the lateral element (A–D) and anti-SYP-1 to visualize central region formation of the SC (E–H). Insets represent antibody only images of nuclei indicated by the arrows to facilitate the observation of both the continuity and distribution of the observed signals. In cra-1 mutants, HTP-3 is observed localizing continuously along chromosomes at the transition zone and pachytene, indicating normal lateral element formation. In contrast, the SYP-1 signal is observed mostly surrounding chromosomes instead of being directly localized onto chromosomes at the transition zone and is observed in variable levels along unsynapsed chromosomes at pachytene. Bars, 2 µm.