A C-terminally truncated human SRF cDNA encoding amino acid residues 1-412 was fused to the transcription activation domain of the herpes simplex virus protein VP16. This was preceeded by a splice acceptor site, a PGK-puromycin selection cassette, and a stop cassette composed of four SV40 polyadenylation signals. The selection cassette and stop cassette were flanked by loxP sites. This construct was then inserted following exon I of the endogenous gene. Despite the requirement of cre recombination to removed the stop cassette and achieve full SRF/VP16 expression, some leaky read-through transcript expression is detected in the retina. (J:172655)