The cDNA encoding enhanced green fluorescent protein (EGFP) from the jellyfish Aequoria victoria was inserted downstream of the "CAG promoter" which consists of the cytomegalovirus immediate early (CMV-EI) enhancer followed by a 1.3-kb DNA segment including the promoter, first exon and first intron of the chicken beta-actin gene. (J:87415, J:160962)