Analysis of chromosome condensation in Scc3 point mutants.

<p><b>A.</b> Strains YOG3021 (<i>SCC3-6HA scc3-6</i>), YOG3024 (<i>scc3-Y371A-6HA scc3-6</i>) and YOG3025 (<i>scc3-K372A-6HA scc3-6</i>), were grown at permissive temperature (23°C) and arrested at G1 using α-factor. The cells were shifted to restrictive temperature (35.5°C) and re-arrested in the G2/M phase using nocodazole. Nuclei were spread and the bulk DNA was stained with DAPI. The morphology of the <i>rDNA</i>-loop of 100 nuclei of each strain was scored (n = 3). <b>B.</b> Representative photomicrographs of wild-type <i>rDNA</i> loops (left panel) and condensation defects at the <i>rDNA</i> locus. Arrow indicates the rDNA region.