“…Efforts have been made to produce transgenic hPSC lines with regulatable gene expression (Du et al, 2009; Vigna et al, 2002; Xia et al, 2008; Zhou et al, 2007). While expression of transgenes (often GFP) can be regulated in stem cells and their differentiated progenies at an early stage, more than often transgenes are no longer expressed and regulatable in mature cells, including neurons (Cherry et al, 2000; Ellis, 2005; Laker et al, 1998; Yao et al, 2004).…”