The Ple155-EGFP plasmid (pEMS1424) was created by inserting the Ple155 MiniPromoter (derived from specific promoter/enhancer/regulatory regions of the human Purkinje cell protein 2 (PCP2) gene) into the multiple cloning site of the pEMS1306 plasmid vector backbone. This placed the Ple155 MiniPromoter upstream of a minimal F5 mutant-frt site, a Kozak consensus sequence, an enhanced green fluorescent protein (EGFP; with mutated TAA to TTA stop), a tetracysteine residue, a nuclear localization signal, a minimal wildtype frt site, an SV40 early polyA signal, a human HPRT complementary sequence (containing exon 1, intron 1, exon 2, and part of intron 2), a mouse 3' Hprt homology arm, an I-Sce linearization cut site, and a mouse 5' Hprt homology arm. This Ple155-EGFP construct was targeted as a single copy knock-in to the Hprtb-m3 mutant locus on the X Chromosome via electroporation into mEMS1204 embryonic stem cells. (J:164356)