Fig. 4. lin-35 acts as a negative regulator of cell-cycle progression. (A) Expression of the rnr::GFP S-phase marker in cyd-1(he112) (left) and lin-35(RNAi); cyd-1(he112) (right). Nomarski images (top) and corresponding epifluorescent images (bottom) show several cells of the P and intestinal lineages. In the cyd-1 animal, only autofluorescence of the intestinal cells is detectable, whereas lin-35 RNAi resulted in expression of rnr::GFP in the P cells and other lineages. (B) Quantitative measurements of DNA content in the intestinal nuclei (gray bars) of wild-type (WT) and mutant animals of indicated genotype. Body wall muscles (black bars) serve as 2n DNA standard. (C) Rescue of postembryonic cell divisions by lin-35. The cell number in the P2-P10 and intestinal lineages were counted in animals of indicated genetic backgrounds. Scale bars: 10 µm. Values indicated are mean±s.e.m.