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. Author manuscript; available in PMC: 2006 Dec 22.
Published in final edited form as: Science. 2006 Jul 21;313(5785):367–370. doi: 10.1126/science.1128242

Fig. 2.

Fig. 2

The segmental aneuploidies on chr5 reflect isochromosome structures. (A) All strains from Fig. 1B contain a unique restriction fragment that spans the Cse4p binding site (lanes 2 to 5, 9, and 11 to 13). Southern blot of Eco NI–digested genomic DNA probed with Cse4p binding site sequence (black bar) detects an ~10-kbp fragment diagnostic of i(5L) structure. Differences in the size of this fragment are due to polymorphic insertion sequences (Fig. 1B). WT: wild type (SC5314), lanes 1 to 15: YJB8734, YJB8735, YJB8736, YJB8737, YJB8738, YJB8739, YJB8740, YJB9309, YJB9311, YJB9175, YJB9180, YJB9185, YJB8640, YJB9613, and YJB8638. Lane designations are identical for all other parts of this figure. (B to H) The isochromosome is either independent or attached to a homolog of chr5. Whole-chromosome CHEF gels stained with ethidum bromide (B), blotted, and probed with chr5L (C) or chr5R (D) reveal an independent isochromosome (lanes 2 to 4, 9, and 12) or an attached isochromosome (lanes 5 and 11). Sfi I digestion of whole chromosomes separated by CHEF and stained with ethidium bromide (E); blotted; and probed with chr5L (F), chr5R (G), and chr5I (H) probes [diagramed in (J, K, and L)] show that the independent isochromosome (lanes 9, 12, and 13) does not contain an Sfi I site. Sfi I digestion of the attached isochromosome (lane 11) releases fragments expected if i(5L) were attached to the left arm of whole chr5. (I) The attached isochromosome includes a telomere-telomere junction. Southern blot analysis of Sac I–digested genomic DNA probed with a chr5L telomere-adjacent probe detected a 10-kbp telomere fragment in all wild-type (WT) and parental (P) strains and an additional larger fragment in YJB8738 (lane 5), as would be expected if two chr5L arms attached via telomere sequence (L). YJB9180 contains a complex attachment not including this Sac I fragment. (J to L) Diagrams, including relevant restriction sites and probes: (J) normal chr5, (K) independent i(5L), and (L) attached i(5L). The centromere region (inverted repeat and central unique sequence) is not to scale.