Time-lapse imaging of wild type embryos showed that the level of SPD-2 present on the centrosome increased over time, reaching a maximum at the metaphase to anaphase transition. In
spd-5(RNAi) embryos, no accumulation of GFP-SPD-2 could be detected as the cell progressed through mitosis, although a small structure was always present. In a separate set of experiments, SPD-2 labeling was restricted to the centriolar region in
spd-5(RNAi) embryos, as judged by its colocalization with the centriolar protein SAS-4. Together, these results suggest that SPD-5 is required for the accumulation of SPD-2 on the PCM, but not for its centriolar association. However, it is certain that this is not due to undetectable residual SPD-5 left after RNAi.