fli-1 mutants display germ line morphogenesis defects (the Glm phenotype). In all images, the distal tip of the gonad is to the left. In images (C), (D), (E), (G), and (H), the approximate extents of mitotic zones (M), transition zones (T), and meiotic pachytene zones (P) are indicated. (A) and (B) Differential Interference Contrast (DIC) images of wild-type and fli-1(ky535) gonads. A wild-type gonad had a germ nucleus-free rachis in the meiotic zone whereas a fli-1(ky535) animal displayed chains of nuclei crossing the rachis (arrowheads in (B)). (C-E). Epifluorescence images of DAPI-stained gonads from wild-type, fli-1(ky535), and fli-1(tm362)/+ animals. Wild-type shows a nucleus-free rachis, whereas fli-1(ky535) and fli-1(tm362)/+ displayed chains of nuclei crossing the rachis (arrowheads). (F) DIC image of a gonad from an rrf-1 mutant animal subject to fli-1 RNAi (rrf-1 animals are defective for somatic RNAi but not germ line RNAi). Arrowheads indicate nuclei in the rachis. (G) and (H) Gonads from wild-type and fli-1(ky535) fed BrdU-containing bacteria for 5 minutes and fixed and stained with DAPI and anti-BrdU antibody. Nuclei in the mitotic zone of both wild-type and fli-1(ky535) accumulated BrdU. No BrdU-positive nuclei were seen in the meiotic pachytene regions, including the misplaced nuclei in fli-1(ky535). The scale bar in (A) = 10 μm for (A-H).