Fig. 2.

iSuRe-Cre DNA construct, ES cells, and mice. a iSuRe-Cre DNA construct used to produce gene-targeted or transgenic ES cells and mice. ROSA26 hom., ROSA26 locus homology arms; INS, chicken β-globin HS4 insulator sequence; FRT, short DNA sequences recognized by the recombinase Flp allowing deletion of the PGK-Neo selection cassette; P1-P4, primers used to genotype ES cells or mice. For further abbreviations and their definitions see also Fig. 1c legend. b PCR result with primers detecting the integration of the vector in the ROSA26 locus of ES cell clones 1–18. c PCR result with primers detecting the presence of the iSure-Cre allele in the genome of ES cells 1–18. d Representative images of different ROSA26-targeted (Gt(ROSA)26Sor) ES cell clones at baseline. N-PhiM is expressed if the allele is non-recombined, and MbTomato marks cells that had recombination of the construct without induction. Clone #6 has a higher proportion of non-recombined N-PhiM+ cells. e Representative images of different Tg(iSuRe-Cre) ES cell clones at baseline. Clone #18 has a higher proportion of non-recombined N-PhiM+ cells. f Mouse chimeras generated with Gt(ROSA)26Sor-iSuRe-Cre ES cell clone #6 were interbred with Rbpj^flox/flox animals, and the progeny were genotyped for the Rbpj and iSuRe-Cre alleles. All animals containing the iSuRe-Cre allele in the ROSA26 locus had deletion of the Rbpj-floxed allele and expressed the MbTomato reporter in all cells. g Mouse chimeras generated with Tg(iSuRe-Cre) ES cell clone #18 were interbred with Rbpj ^flox/flox animals, and the progeny were genotyped for the Rbpj and iSuRe-Cre alleles. Animals containing the Tg(iSuRe-Cre) allele did not have deletion of the Rbpj-floxed allele and did not express the MbTomato reporter. Instead they expressed the N-PhiM reporter due to the absence of Cre activity. Scale Bars 100 μm