Significant increase of self-renewal in hematopoietic cells after forced expression of EVI1

EVI1 was first identified as a preferential integration site of ecotropic retroviruses in the MDS1/EVI1 genomic locus leading to myeloid tumors in susceptible mice. Later studies showed that retroviral integration in the MDS1/EVI1 locus results in the emergence of a non-malignant dominant hematopoietic stem cell clone in non-susceptible mice strains, in non-human primates, and in patients, suggesting that a gene encoded by the locus could affect the self-renewal potential of a cell. The locus encodes two genes. One of them, EVI1, has long been associated with myeloid leukemia. To understand whether EVI1 has a role in self-renewal control, we forcibly expressed EVI1 in the bone marrow progenitors of two mice strains that differ in their proliferation and self-renewal potential. By comparing the response of the hematopoietic cells to EVI1, we conclude that EVI1 has a role in prolonging the self-renewal potential of the cells and that this ability of EVI1 is limited and modulated by inherent characteristics of the cells. (c) 2007 Elsevier Inc. All rights reserved.