Tissue specificity of GFPcre-mediated recombination and expression of the EpoR and GFPcre in ErGFPcre mice. (A) Whole-mount lacZ stainings of R26R-positive (left) and GFPcre/R26R–double-positive (right) embryos at developmental stage E13.5. (B) LacZ stainings performed on sagittal cryosections of embryos (E13.5) hemizygous for GFPcre and R26R. FL indicates for fetal liver; and BV, blood vessel. X-Gal stainings on whole-mount and tissue-sections were performed according to standard procedures.33 Images were acquired using a Zeiss Stemi SV11Apo binocular microscope in combination with a Zeiss AxioCam Color camera. (C) Southern blot analysis of ErGFPcre-R26R reporter mice hemizygous for GFPcre and R26R. EcoRV-digested genomic DNA from different tissues and Ter119-positive and -negative sorted bone marrow fractions were analyzed by Southern blot analysis (for details see Figure 5A). The fragments representing the excised (-◃-) and the nonrecombined (◃-◃) reporter allele are indicated. (D) RT-PCR analysis of different tissues derived from adult ErGFPcre mice hemizygous for GFPcre. Total RNA derived from tissue samples was reverse transcribed and cDNA samples were used for PCR analysis monitoring EpoR and GFPcre expression. PCR analysis monitoring beta-actin was used to confirm comparable total mRNA levels within the samples.
