This transgene contains the coding sequence for enhanced green fluorescent protein (EGFP), followed by a polyadenylation signal, inserted into the mouse genomic bacterial artificial chromosome (BAC) RP23-73H21 at the ATG transcription initiation codon of the insulin-like growth factor 1 gene (Igf1) so that expression of the reporter mRNA/protein is driven by the regulatory sequences of the mouse gene. (J:100256)