Figure 1. SPD-3 is required for chiasma formation and localizes to mitochondria.

(A) Projection of diakinesis oocytes stained with DAPI. Note that while WT oocytes display 6 DAPI-stained bodies, corresponding to 6 bivalents, the spd-3(me85) mutant oocyte displays 9 DAPI-stained bodies, demonstrating a partial failure in chiasma formation. (B) Diagram of the spd-3 gene indicating the position of the me85 mutation and two deletion alleles. (C) Western blot probed with anti-SPD-3 antibodies, arrowheads point to the endogenous SPD-3 protein, arrow points the SDP-3::GFP fusion protein, and the asterisks labels a band that may correspond to a truncated SPD-3 protein made by spd-3(me85) mutants. The western blot shown at the bottom was probed with anti-tubulin antibodies and was used as a loading control. (D) Pachytene region of an ex-vivo germ line from a worm expressing SPD-3::GFP, which shows a localization pattern similar to that observed in (E) for immunolocalization of the mitochondrial protein cytochrome C in the pachytene region of fixed germ lines. (F) Western blots from cytosolic and mitochondrial extracts stained with the indicated antibodies. Note that SPD-3 is only found in the mitochondrial extract. (G) Electron micrographs of mitochondria purified from worms expressing SDP-3::GFP, and labeled with anti-GFP (left, 10 nm gold) and anti-NDUFS3 antibodies (right, 18 nm gold). (H) Whole germ lines from 16–18 hours post L4 worms stained with DAPI.