Submitted April 10, 2002
Accepted September 2, 2002
E26 leukemia virus converts primitive erythroid cells into cycling multilineage progenitors
Kelly M McNagny and Thomas Graf*
Medical Genetics, The Biomedical Centre, University of British Columbia, Vancouver, British Columbia, Canada
Developmental and Molecular Biology, Albert Einstein College, Bronx, NY, USA
* Corresponding author; email: graf{at}aecom.yu.edu.
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 two 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 sub-populations of pre-circulation 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.
