Fig. 1. Identification and characterization of cyd-1 and cdk-4 mutant animals. (A) Positions of cells in the ventral cord precursor (P, green) and intestinal (I, gray) lineages in late L1 wild-type (top) and cell-cycle mutant (bottom) larvae. The lineages of an individual P and I cell are indicated for each genotype (right). (B) Postembryonic blast cells remain undivided in cyd-1 and cdk-4 mutants, as indicated for intestinal and P precursor cells in the enlarged sections (right). The panels show a late L1 wild-type larva (top) and similar stage cyd-1(he112) mutant (bottom) after fixation and DNA staining with propidium iodide. (C) Expression of the rnr::GFP S-phase marker in wild-type animal (left) and cyd-1(he112) mutant (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. (D) Quantitative measurements of DNA content in the intestinal nuclei (gray bars) of wild-type animals and mutant strains of indicated genotype. Body wall muscle cells (black bars) serve as 2n DNA standards. Scale bars: 10 µm. Values indicated are mean±s.e.m.
