A tamoxifen-inducible CreER(T2) fusion gene was introduced to the start codon of the mouse Gata1 gene contained within BAC RP23-443E19. The modified BAC was introduced to C57BL/6J zygotes. Lines L245 and L259 were generated and shared similar profiles of the erythroid lineage-specific cre activities. The line L259 was used for the studies. The insertion site and copy number of the transgene are unknown.