Isolation of genes highly expressed in early and late stages of Friend virus-induced erythroleukemia in mice.

We isolated two genes that are highly expressed in Friend erythroleukemia. The first one, expressed at an extremely high level in a late-stage tumorigenic cell line F5-5, was found to be a species of intracisternal A-particle. Most of those genomes in F5-5 DNA were not amplified nor rearranged compared with those in the normal cell DNA, suggesting transcriptional activation. Another late-stage cell line T3K showed similar results. The second gene, highly expressed in early-stage cells but weaker in late-stage cells, was identified as one of the heme-synthesizing enzymes, uroporphyrinogen decarboxylase. Usefulness of these two genes for the analysis of erythroid transformation and differentiation will be discussed.