This transgene contains the coding sequence of enhanced green fluorescent protein (EGFP), with a polyadenylation signal, inserted into the RP23-9A20 mouse genomic bacterial artificial chromosome (BAC) at the ATG transcription initiation codon of the chemokine (C-X-C motif) receptor 4 (Cxcr4) gene so that expression of the reporter mRNA/protein is driven by the regulatory sequences of the mouse gene. (J:100296, J:100256)