A cassette containing the human PLG cDNA from nucleotide -13 (A of ATG initiation codon as +1) to +2476 (including the entire coding sequence) was followed by the green fluorescent protein (EGFP) coding sequence, preceded by an internal ribosome entry site sequence (IRES) and a bacterial kanamycin-resistant gene (KAN). A chimeric intron with optimized splice signals from the pCI expression vector was placed upstream of the PLG cDNA. Homologous recombination between the transgene targeting construct and the murine Alb BAC was carried out in E. coli, replacing the murine Alb gene (from nucleotide -12 to exon 12) by the transgene cassette. EGFP expression is not detected.