Tg(Nr4a1-EGFP/cre)820Khog

The 170 kb C57BL/6J mouse bacterial artificial chromosome (BAC) RP24-366J14, containing the entire Nr4a1 locus (Nur77) was obtained. An eGFP-hCre fusion protein cDNA sequence (enhanced green fluorescent protein fused to a codon-optimized "humanized" Cre to improve translational efficiency in eukaryotic cells), a frt-flanked neo cassette, and a TGA STOP codon was inserted into the ATG start site of the Nr4a1 gene on the RP24-366J14 BAC via homologous recombination/BAC recombineering. The frt-flanked neo was removed via arabinose treatment during BAC recombineering. A ~135 kb fragment from the modified BAC harboring the targeted Nr4a1 locus as well as 60 kb sequence flanking each side of the Nr4a1 locus (including the Acvr1b, A330009N23Rik, Grasp, 9430023L20Rik and 6030408B16Rik loci) was purified and then microinjected into C57BL/6J embryos. The resulting Nur77GFP BAC transgenic founder mice were bred with C57BL/6NCr mice. Transgenic mice from the B6-820 founder line were found with high GFP expression levels in myeloid lineage cells from spleen (but not lymph node), as well as low GFP expression levels in T and B lymphocytes. (J:172415)