FIG. 5.
Loss of Mei-41 function in mitotically active eye discs and Kc cells results in loss of the replication checkpoint. (A and B) Discs from mei-41RT heterozygotes or homozygotes were treated with HU, and the mitotic cells of the eye discs were quantitated. (C) Kc cells treated with water (mock) or dsRNAs directed against mei-41 for 48 and 72 h were also treated with HU for 12 or 24 h before staining with the mitosis marker anti-phospho-H3 antibody. The mitotic index is expressed as a percentage of mitotic cells observed in the absence of HU treatment. RT-PCR analysis of the Kc cells treated with water or mei-41 dsRNAs after 48 h shows that mei-41 is not expressed in these cells. Actin was used as internal control for the integrity of the cDNAs. (D) Kc cells that are depleted of mei-41 continue to incorporate BrdU, at least for 72 h. In addition, the frequency of mitotic cells (metaphase, anaphase, and telophase) was determined following phospho-H3 and propidium iodide staining.