This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Construction of an inducible plasmid: For regulated expression of enhanced green fluorescent protein (EGFP), lentiviral vectors with doxycycline inducible promoter system based on hybrid repressor tetR-VP16 or tetR-KRAB can be used. In absence of doxycycline, the hybrid repressor will bind specifically to tetO and suppresses the nearby promoter controlling EGFP expression. Conversely, in the presence of doxycycline, the repressor will be sequestered away from tetO, thus permitting expression of EGFP. tetR: tetracyclin repressor;VP16: HSV VP16 transactivator domain;KRAB: KRAB domain of human Kox1;tetO: tet operator sequence Once the constructs are ready the hESC will be transfected and checked for GFP expression ad injectedin to E13.5 mouse embryonic kidney and organ cultured for 7 days. The kidenys will then be subjected to immno-histochemical analysis.