Cover image

C. elegans fzr-1 synthetically interacts with lin-35/Rb to regulate global cell proliferation. Shown here in the foreground are schematic worm colonies representing a lin-35 synthetic-lethal screen analogous to an S. cerevisiae sectoring assay. The GFP⁺ animals (green) carry an extrachromosomal array containing wild type rescuing copies of lin-35 and a GFP reporter; the GFP animals (pale yellow) have lost this array. The worm colony shown in the lower left failed to segregate wild type-appearing (large) GFP animals, indicating the presence of a mutation that makes survival dependent upon the lin-35-expressing array. Shown in the background are GFP⁺ and GFP animals from a lin-35; fzr-1 double-mutant strain identified by such a screen. The GFP animals are small and display a hyperproliferation and sterile phenotype. (For details, see Fay et al., p. 503.)