Fig. 2. CPS-6 relocates from the intermembrane space of paternal mitochondria to the matrix following fertilization to promote PME.

(A) A diagram of C. elegans mtDNA, the uaDf5 deletion, primers used in the nested PCR assays, and sizes of PCR products in N2 and uaDf5/+ animals. (B and C) Hermaphrodites and MTR-stained males were mated as indicated. Males also carried smIs42, an integrated P_sur-5sur-5∷gfp transgene used to track cross progeny (see Fig. S2A). A single unfertilized oocyte and a single cross-fertilized embryo or larva (MTR or GFP positive) at the indicated stage was analyzed by PCR. uaDf5/+ and N2 hermaphrodites were controls. (D) Quantification of MTR-stained paternal mitochondrial clusters in 64-cell embryos from the indicated crosses with MTR-stained males. Means ± SEM; n=20 per cross. ** P < 0.0001 using unpaired Student's t-test. “n.s”, no significant difference. (E, F) Five cross-fertilized embryos (E) or transgenic embryos (F) at approximately 100-cell stage from the indicated crosses were analyzed by PCR. (G to J) Representative immuno-EM images of mitochondria in N2 spermatozoa and paternal mitochondria in zygotes from the indicated cross. CPS-6-specific and PD-E2-specific immunogold particles are marked with arrowheads. Scale bars: 300 nm. (K) Histogram of the distances of 15 nm immunogold particles from the mitochondrial membrane, illustrating CPS-6's movement after fertilization. Numbers in parentheses indicate the numbers of immunogold particles scored. *** P < 0.0001 using Mann-Whitney U test. cps-6(tm3222) was used in all figures.