Fig. 5.

SET-2 but not ASH-2 is required for H3K4 methylation in the distal germ line. (A–H) Gonads were dissected and stained with anti-H3K4me3 (Abcam; ab8580, A–D) or H3K4me2 (Abcam; ab7766, E–H) (green) and DAPI (blue). (Scale bar, 20 μm.) (I) Close-up images of the distal and medial region of gonads (boxed regions in cartoon) from wild-type and mutant animals. (J) Maximal pixel intensity values for images in I. Error bars show SEM, asterisks denote Mann–Whitney P values <0.05 when comparing the same region between different backgrounds. (K–U) Loss of SET-2 function impairs fertility. (K) set-2(bn129) mutants display progressive sterility. Representative data from one experiment are shown. For experiments at 20 °C, offspring from individual animals (n = 5) were counted at the third generation (F₃) and then at F₁₂, F₁₅, and F₁₇, giving the total brood size. For experiments at 25 °C, scoring was every generation starting at F₁. Independent lines are depicted by different shades of gray. Similar results were obtained in at least five independent experiments. (L–U) Germ-line defects in set-2 mutant worms. (L) Wild-type proximal gonad; (M) reduced number of oocytes; (N) absence of fertilized embryos in the proximal gonad of set-2 animals (dotted lines); (P) abnormal nuclei in the distal germ line of set-2 animals (arrows) compared with wild type (O). (Q–U) Diakinetic nuclei showing six DAPI-stained bodies in wild type (Q) and nuclei with either fewer (R and S) or more (T and U) than six DAPI-stained bodies in set-2 mutant animals. In R, a DAPI-stained body with an abnormal shape is shown with an arrow.