Cell cycle arrest in response to γ-rays is normal in the hsr-9(ok7599) mutants.

<p>Wild-type N2, <i>hsr-9(ok759)</i>, <i>hsr-9(ttTi14815)</i>, and <i>atm-1(gk186)</i> worms were treated with 75 Gy of γ-irradiation as L4 stage larvae. Twelve hours later, gonads were isolated and stained with DAPI. (A) Germ cells in the mitotically proliferating regions of the gonads (within 75 µm of the distal tip cell) were counted under a fluorescence microscope (30 gonad arms per data point). (B) The diameters of 40 nuclei in the mitotically proliferating region of each gonad arm were measured (number of nuclei = 800 for each strain before and after irradiation) for wild-type N2, <i>hsr-9(ok759)</i>, and <i>atm-1(gk186)</i> worms. The percentages of the total nuclei of different diameters are plotted. Very small (<2 µm) and very large (>7 µm) nuclei were grouped together.