Generating a 1.6 Mb deletion between the <i>Lipi</i> and <i>Usp25</i> loci.

<p>(A) The targeting vectors contain a <i>loxP</i> site (arrowhead), a selectable antibiotic resistance gene (<i>N</i> (neomycin) or <i>P</i> (puromycin)), a coat color marker (<i>Ty</i> or <i>Ag</i>) and part of the <i>Hprt</i> gene (5′ or 3′) were targeted as shown. The colored boxes (green and red) indicate the location of the probes (5′ and 3′, respectively) used for Southern blotting (B) The targeting events were confirmed by Southern blot analysis showing an additional <i>Stu</i>I fragment of 17 kb compared with the wildtype allele (15 kb) for the <i>Lipi</i> locus and an additional <i>BamH</i>I fragment of 22.6 kb compared with the wildtype allele (12 kb) for the <i>Usp25</i> locus. B, <i>BamH</i>I; S, <i>Stu</i>I; P, puromycin; N, neomycin; Ty, <i>Tyrosinase</i>; Ag, <i>Agouti</i>. (C) Interphase FISH analysis with BAC probes that map in the region of the deletion (red) and outside (green). Chromosomes from the ES cells double-targeted in <i>cis</i> (<i>Ms1Dja/+</i>) showed two green and only red signal due to the deletion of the <i>Lipi–Usp25</i> region, while chromosomes from the wildtype ES cells showed two green and two red signals.