Fig. 3. Loss of URI-1 blocks cell cycle progression in the C. elegans germline. (A) (Left) Quantification of G2/M phase cells in untreated wild-type (n=35, dark) and uri-1(RNAi)F1 (n=35, grey) synchronized adult hermaphrodites (^*P=5.2x10^-5). Error bars represent s.d. (Right) DAPI and PH3 staining of the distal part of the germline of a uri-1(RNAi)F1 and a wild-type worm. The arrowheads indicate mitotic germline cells with apparently condensed chromosomes and different extent of enlargement. This DNA morphology accumulates in germlines upon loss of uri-1 function and resembles prometaphases which are not recognized by the PH3 antibody (Cy3). Scale bar: 10 µm. (B) (Right) Staining with anti-phospho-histone H3 antibody (Cy3) of germ cell nuclei (visualized with DAPI) in the distal region of the gonad of the indicated strains. (Left) PH3-positive nuclei were counted per gonad arm in synchronized adults uri-1(tm939) homozygous (n=24), uri-1(RNAi)F1 (n=65) and wild type (n=65, Student's test ^*P=7.9x10^-8, ^#P=1.0x10^-4). Scale bar 10 µm. Error bars indicate s. d. (C) Anti-PH3 (Cy3) and DAPI staining of a homozygous uri-1(lf) mutant and wild-type gonads. Arrowheads indicate sperm. Scale bar: 10 µm. Anterior is towards the left and dorsal is towards the top.