Demonstration of proviral integration analysis of in vitro clonogenic progenitor cells derived from retrovirally transduced murine BM cells. Individual colonies were isolated from methylcellulose cultures containing total EGFP-transduced BM cells, FACS-sorted EGFP-negative or EGFP-positive cells, and analyzed by PCR using primers specific for EGFP (EGFP). As a positive control for PCR, primers specific for the murine peripheral cannabinoid receptor (mCb2) were used.58