Loss of one allele of Ebf1 impairs pre-B cell (B220+CD19+CD43low/negIgM-) expansion. In order to better understand the underlying cause of the reduced pre-B cell compartment in Ebf1+/- mice, we sorted pro-B (B220+CD19+CD43highIgM- ) as well as pre-B cells from Wt and Ebf1 heterozygote mutant mice and performed Affymetrix based microarray gene expression analysis.
Early B-cell factor 1 regulates the expansion of B-cell progenitors in a dose-dependent manner.
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Foxo1 and Ebf1 deficiency leads to a similar disruption of normal B-cell development at the level of the common lymphoid progenitor (CLP). Both mouse strains display the existance of LY6D+ CLPs but a marked/complete lack of proB cells.
Positive intergenic feedback circuitry, involving EBF1 and FOXO1, orchestrates B-cell fate.
Specimen partView Samples
Ebf1 is a transcription factor with documented, and dose dependent, functions in both normal and malignant B-lymphocyte development. In order to understand more about the role of Ebf1 in malignant transformation, we have investigated the impact of reduced functional Ebf1 dose on early B-cell progenitors. Gene expression analysis in loss and gain of function analysis suggested that Ebf1 was involved in the regulation of genes of importance for DNA repair as well as cell survival. Investigation of the level of DNA damage in steady state as well as after induction of DNA damage by UV light supported that pro-B cells lacking one functional allele of Ebf1 display a reduced ability to repair DNA damage. This was correlated to a reduction in expression of Rad51 and combined analysis of published 4C and chromatin Immuno precipitation data suggested that this gene is a direct target for Ebf1. Even though the lack of one allele of Ebf1 did not result in any dramatic increase of tumor formation, we noted a dramatic increase in the formation of pro-B cell leukemia in mice carrying a combined heterozygote mutation in the Ebf1 and Pax5 genes. Even though the tumors were phenotypically similar and stable, we noted a large degree of molecular heterogeneity well in line with a mechanism involving impaired DNA repair. Our data support the idea that Ebf1 controls homologous DNA repair in a dose dependent manner and that this may explain the frequent involvement of Ebf1 in human leukemia
Ebf1 heterozygosity results in increased DNA damage in pro-B cells and their synergistic transformation by Pax5 haploinsufficiency.
Specimen part, Cell line, TimeView Samples