CNIH-2:IRES:GFP was cloned into pSCA1 [49]. Semliki forest viral particles were produced by standard procedures [48]. CNIH-2 was cloned into the HIV-derived lentiviral vector CMV-GFP [50]. High-tighter lentivirus preparations were produced by standard procedures [51]. Used virus solutions had a titer between 107 and 109.