Generation and Characterization of Radiation-Induced Deletion Complexes in Mouse ES Cells

<div><p>(A) Insertion of a negative selectable marker (cassette Neo-tk: Hsv-thymidine kinase/neomycin resistance) into a predetermined locus by homologous recombination in F1 hybrid (129/SvJae x C57BL/6J) ES cells (C57BL/6J chromosome represented with a black centromere; 129/SvJae chromosome represented with a white centromere).</p><p>(B) Treatment of the neomycin-resistant targeted cells with radiation to induce the deletions.</p><p>(C) Selection in medium containing 1,2′-deoxy-2′-fluoro-β-D-arabinofuranosyl-5-iodouracil of the colonies having lost the <i>tk</i> gene.</p><p>(D) Characterization of the deletion breakpoints by amplification of the DNA from these clones using primers corresponding to genetic polymorphic markers (represented under the chromosome map by letters a–j) flanking the site of the targeted integration. Deletions are represented as solid boxes.</p>