Biochemical and Biophysical Research Communications, Vol.275, No.2, 292-294, 2000
Regulation of ferritin mRNA translation in primary erythroblasts: Exogenous c-Kit plus EpoR signaling mimics v-ErbA oncoprotein activity
In general, translation efficiency of ferritin mRNAs is modulated by variations in iron supply. In primary avian erythroblasts undergoing short-term proliferation, however, ferritin heavy chain (ferH) mRNA is repressed at all iron levels, Yet, expression of v-ErbA oncoprotein is sufficient to reinduce ferH mRNA utilization at physiological iron concentrations. Since overexpression of the receptor tyrosine kinase c-Kit and erythropoietin receptor (EpoR) stimulates longterm proliferation of primary erythroblasts like v-ErbA, we analyzed the impact of cooperation between c-Kit and EpoR on the regulation of iron storage. Whereas endogenous c-Kit in combination with exogenous EpoR had no significant effect, ectopic overexpression of both receptors abolished translational repression of ferH mRNA upon iron administration. Thus, high-intensity signaling through c-Kit plus EpoR pathways mimics the v-ErbA-mediated regulatory phenotype.
Keywords:ferritin H chain mRNA;translational control;v-ErbA oncoprotein;c-Kit;erythropoietin receptor