The 1.934 kb mylpfa promoter region was PCR-amplified from zebrafish embryo cDNA library and H2B-GFP cDNA was obtained from pBOS-H2BGFP plasmid (BD Pharmingen) by restriction enzyme digestion. Both the mylpfa promoter and H2B-GFP cDNA were cloned into pBSKI2 vector (Amagen), with the promoter placed upstream of the H2B-GFP cDNA.