le mutants rescue post embryonic seam cell defects in bro 1 single mutants. bro 1 is the C. elegans CBFb homolog that is selleck chem required for the normal proliferation and differentiation of seam cells. To determine whether or not lin 35 and fzr 1 mutants play a role in the defective postembryonic cell proliferation in the mdf 2 background, we examined genetic interactions by constructing lin 35, mdf 2 and fzr 1, mdf 2 double mutants. We found that 100% of the lin 35, mdf 2 double mutants are sterile, making the analysis of seam cell development difficult. We also found synthetic enhanced interaction between fzr 1 and mdf 2 mutants. The ok380 deletion removes 442 nucleotides between intron 3 and exon 3 and is predicted to result in truncated FZR 1, which may or may not be functional.
fzr 1 homo zygotes can be easily propagated and exhibit no major developmental Inhibitors,Modulators,Libraries abnormalities. As reported previously, mdf 2 homozygotes can be maintained at 20 C indefinitely but display a severely reduced Inhibitors,Modulators,Libraries brood size of approximately 40 progeny worm of which only 40% develop into adults. Once we constructed fzr 1, mdf 2 homozygotes, we immedi ately observed that these worms are extremely difficult to propagate due to the small number of progeny that reach adulthood. Our detailed analysis of fzr 1, mdf 2 double mutants revealed that they have significantly reduced brood sizes and sig nificantly reduced numbers of fertile adults, resulting in only two or three fertile adult progeny per hermaphrodite compared to about 10 to 15 fertile adults produced by mdf 2 homo zygotes.
Furthermore, we observed that while mdf 2 homozygotes displayed CIN as determined by high incidence of males phenotype, fzr 1 increases this chromosome instability to 6%. Even though fzr 1, mdf 2 double mutants are diffi cult to grow, we collected enough adult progeny for analysis of postembryonic seam cell proliferation. Inhibitors,Modulators,Libraries As expected, we found that fzr 1 homozygotes had on average 15. 98 SCM,GFP nuclei not significantly different from wild type. However, we found that fzr 1 had no effect on seam cell proliferation in the mdf 2 back ground as fzr 1, mdf 2 double mutants had on aver age 14. 82 seam cell nuclei Inhibitors,Modulators,Libraries not significantly different from the mdf 2 animals. Taken together, these data suggest that although mdf 2 displays synthetic lethality and enhanced pheno type with lin 35 and fzr 1, this pathway is unlikely explanation for postembryonic cell proliferation defect observed in the absence of MDF 2 spindle checkpoint using the seam cell lineage.
Hypomorphic mutant fzy 1 partially suppresses lethality of mdf 2 mutants GSK-3 and completely rescues seam cell defects The hypomorphic Y-27632 mechanism mutant allele of fzy 1,h1983, was iso lated from the screen for suppressors of the mdf 1 lethal phenotype in search for additional components that function in the metaphase to anaphase transition. The h1983 allele is a missense mutation and the resulting FZY 1D433N mutant protein cannot properly bind the APC C substrate IFY 1. Subsequently,