Blood, 1 February 2003, Vol. 101, No. 3, pp. 1103-1110
NEOPLASIA
E26 leukemia virus converts primitive erythroid cells into
cycling multilineage progenitors
Kelly M. McNagny and
Thomas Graf
From the Biomedical Research Centre, Department
of Medical Genetics, University of British Columbia, Vancouver,
Canada and the Department of Developmental and Molecular
Biology, Albert Einstein College of Medicine, Bronx,
NY.
Acute chicken leukemia retroviruses, because of their capacity to
readily transform hematopoietic cells in vitro, are ideal models to
study the mechanisms governing the cell-type specificity of
oncoproteins. Here we analyzed the transformation specificity of 2 acute chicken leukemia retroviruses, the Myb-Ets- encoding E26 virus
and the ErbA/ErbB-encoding avian erythroblastosis virus (AEV). While
cells transformed by E26 are multipotent (designated "MEP" cells),
those transformed by AEV resemble erythroblasts. Using antibodies to
separate subpopulations of precirculation yolk sac cells, both viruses
were found to induce the proliferation of primitive erythroid
progenitors within 2 days of infection. However, while AEV induced a
block in differentiation of the cells, E26 induced a gradual shift in
their phenotype and the acquisition of the potential for multilineage
differentiation. These results suggest that the Myb-Ets oncoprotein of
the E26 leukemia virus converts primitive erythroid cells into
proliferating definitive-type multipotent hematopoietic progenitors.
