Friedreichs ataxia is an autosomal recessive hereditary disease with an incidence of 1:50.000 and prevalence in the Caucasian population. The disease manifests itself in individuals carrying a GAA-repeat expansion within the first intron of the gene encoding the mitochondrial protein frataxin. This GAA-repeat expansion results in deficiency of this protein [DELATYCKI M. B. et al., 2000]. This deficiency leads to oxidative damage, impaired synthesis of the iron-sulfur-clusters, which results in

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... efects of the subunits of the mitochondrial electron transport complexes I, II and III as well as the Fe-S protein aconitase. Additionally as a consequence of the impaired Fe-S cluster formation, a deficiency of the cytochrome C-heme and the heme-dependant complex IV occurs [RÖTIG A. et al., 1997; NAPOLI E. et al., 2006]. The aim of this work was to investigate the influence of hemoglobin synthesis on frataxin expression by incubating the erythroid-leukemia cell line (K562-cells) with hemin, succinyl-acetone or both substances simultaneously. Frataxin protein levels were measured by ECLIA and the mRNA-expression was determined by PCR. We found slightly elevated frataxin protein concentrations, but with no statistically significant difference, and there were no changes in frataxin mRNA-levels. In a murine cell model with primary erythroid progenitor cells we induced erythropoiesis with controlled proliferation and differentiation. During the Epo-induced differentiation hemoglobin-levels increased significantly, wheras the frataxin protein expression decreased, also significantly. Frataxin mRNA-levels decreased, but with no statistical significance. These findings provide a good basis for future work with a frataxin-knockout murine cell culture model to further investigate the role and function of frataxin during hemoglobin synthesis.