Conditional E2A-HLF transgenic mice.

<p><b>(A)</b> Schematic representation of wild type, targeted, and recombined E2A alleles. After Cre recombinase expression, 3’ E2A exons (13, E12, E47 and 16) and the PGKneo cassette are deleted and the human HLF cDNA linked with EGFP by an IRES element is fused in frame to E2A. The expression of Cre-recombinase was driven by the B-cell specific promoters CD19 or Mb1 (CD79a, Igα), or in hematopoietic stem cells by the Mx1 promoter. The phenotypes arising depending on the Cre-recombinase driven promoter are indicated on the right. MPD-like, myeloproliferative disease like. <b>(B)</b> Flow cytometry analysis shows GFP expression from fetal liver (FL) cells of an E2A-HLF/Mx1.Cre embryo and from total bone marrow (BM) of E2A-HLF/Mb1.Cre and E2A-HLF/CD19.Cre mice. <b>(C)</b> Representative western blots show E2A and E2A-HLF protein levels in FACS-sorted progenitor B cells from wild-type (WT, lin-CD19+CD43+) and 2-month-old transgenic (lin-CD19+CD43+GFP+) E2A-HLF/Mb1.Cre and E2A-HLF/CD19.Cre mice. For comparison, E2A and E2A-HLF expression is shown from the non-E2A-HLF cell line REH and from the E2A-HLF+ cell line HAL-01. GAPDH was used as loading control. The E2A/E2A-HLF ratio (shown below) was determined by densitometry.