Cell Growth & Differentiation, Vol 4, Issue 2 125-135, Copyright © 1993 by American Association of Cancer Research We have previously shown that v-erb-B contained within a recombinant murine retroviral vector is capable of transforming pre-B lymphocytes (M. Miller, A. K. Kennewell, and G. Symonds, Leukemia, 6: 18-28, 1992) and early erythroid precursor cells [blast-forming units (erythroid) (M. Miller, A. Kennewell, Y. Takayama, A. Bruskin, J. M. Bishop, G. Johnson, and G. Symonds, Oncogene, 5: 1125-1131, 1990)] in vitro. To determine the sites and nature of v-erb-B-induced transformation in vivo, the hematopoietic systems of lethally irradiated mice were repopulated with v-erb-B-infected bone marrow. All mice became moribund within 4-12 weeks of reconstitution, with a median onset of disease at 6 weeks. Histopathological and flow cytometric evaluation of tissues from diseased mice, as well as morphological and phenotypic analysis (cytochemical as well as molecular) of the cell lines established from the mice, revealed that all but one of the mice examined at postmortem had developed a pre-B lymphoid leukemia or lymphoma. Abnormally high levels of mast cells in the spleen and bone marrow of the remaining mouse indicated a mast cell disease. The development of pre-B lymphoid malignancy in the majority of the reconstituted mice indicates a marked predisposition of v-erb-B to transform cells of the pre-B lymphoid lineage. The reconstitution of lethally irradiated mice with v-erb-B virus-infected bone marrow provides a model system for the analysis of events involved in the initiation and maintenance of acute lymphoid leukemia. Source.