While the main function of MDF 1 may be regulation of APC C activity, the precise role for MDF 2 is currently unknown. fzy 1 homozygotes can be easily propagated and the strain exhibits a slight sellectchem decrease in the brood size and an increase in incidence of males with no apparent abnormalities in growth or morphology. To deter mine whether fzy 1 can rescue lethality of the mdf 2, we constructed fzy 1, mdf 2. We observed that fzy 1 has no significant effect on brood sizes of mdf 2 homozygotes. However, fzy 1, mdf 2 worms produce on average 85% progeny that develop into adults, compared to 40% observed for mdf 2 homozygotes. Further more, the majority of fzy 1, mdf 2 adult progeny are fertile, suggesting that fzy 1 can suppress the sterility caused by the absence of MDF 2.

Also, we observed that fzy 1 decreases incidence of males from 3% observed in the mdf 2 homozygotes to 0. 8% observed in double mutants. Together, these data further confirm that like MDF 1, MDF 2 regulates APC CCDC20 activity during development. Next, we examined if fzy 1 has an effect on seam cell development. Interestingly, we found that fzy 1 homozygotes had on average 16. 04 seam nuclei not significantly different from wild type animals. Furthermore, seam cell development in fzy 1, mdf 2 double mutants appeared to be completely normal. Namely, fzy 1, mdf 2 double mutants had on average 16. 08 seam cell nuclei not significantly different from the wild type or fzy 1 homozygous animals. In addition, the majority of the analyzed fzy 1, mdf 2 young adults had 16 evenly spaced and aligned SCM,GFP nuclei.

These results sug gest that MDF 2 plays an important role in postembryo nic seam cell proliferation by inhibiting the activity of the APC CCDC20. Discussion In this work we have examined for the first time in vivo AV-951 spatiotemporal expression profiles of eight spindle checkpoint genes in C. elegans. Among these eight genes, five are conserved from yeast to human, while three are conserved in higher eukaryotes, including C. elegans. Our study focused on analysis of the expression patterns by using extra chro mosomal arrays. To maximally reduce the effect of mosaicism, the known caveat of this approach, we analyzed a large number of animals for each develop mental stage, and recorded the tissues and cells where GFP expression was consistently observed. On the other hand, we found the mosaicism to be beneficial for a bet ter identification of tissues where GFP is expressed. When promoters drive GFP expression in more than one tissue types, then expression restricted to only small groups of cells, due to loss of the array, offers more con fident identification of these tissues.