The Ple233-EGFP transgene (pEMS1437) was designed with the 1216 bp Ple233 minipromoter (TNNT1-C; derived from a subsection of the promoter and a downstream putative regulatory element from the human troponin T type 1 (skeletal, slow) [TNNT1] gene) upstream of a minimal F5 mutant-frt site, an enhanced green fluorescent protein (with mutated TAA->TTA stop), a nuclear localization signal, a second minimal frt site, an SV40 early polyA signal, and a human HPRT complementary sequence (containing exon1, intron1, exon2, and part of intron2). This construct was targeted as a single copy knockin to the Hprtb-m3 mutant locus on the X chromosome. (J:144244, J:164356)