Identification of TAXREB107 as an erythropoietin early response gene

The protooncogenes c-myc and c-myb are erythropoietin (Epo)-regulated early response genes. They appear to play distinct roles in the growth- and diff erentiation-inducing signals of the hormone. Using a subtractive hybridizat ion strategy, we have identified the murine homolog of the TAX response ele ment-binding protein TAXREB107 as an Epo early response gene in Rauscher mu rine erythroleukemia cells. This was confirmed by Northern blot analyses, w hich showed a fourfold increase in TAXREB107 mRNA after 1 hr of erythropoie tin treatment, After 3 hr the transcript had decreased to approximately two fold above control levels. Inhibition of this induction with antisense olig odeoxynucleotides increased Epo-induced hemoglobinization 2.5-fold. The res ults implicate TAXREB107 in erythropoiesis and support the hypothesis that the TAXREB proteins have functions outside the context of HTLV-I infection.