The transgene comprises a DNA fragment containing the mouse insulin 1 promoter, extending from 8.5 kb upstream of the transcription initiation site to nucleotide +12, driving expression of a fusion gene joining the 7.6-kb coding region of the enhanced green fluorescent protein (EGFP) gene to a 2.1-kb fragment of the human growth hormone 1 gene that confers high-level expression. (J:99450)