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Hematology - Infectious Diseases - Molecular Biology


Expression of Prion Protein in Mouse Erythroid Progenitors and Differentiating Murine Erythroleukemia Cells
Published: Friday, September 02, 2011
Author: Martin Panigaj et al.

by Martin Panigaj, Hana Glier, Marcela Wildova, Karel Holada

Prion diseases have been observed to deregulate the transcription of erythroid genes, and prion protein knockout mice have demonstrated a diminished response to experimental anemia. To investigate the role of the cellular prion protein (PrPC) in erythropoiesis, we studied the protein's expression on mouse erythroid precursors in vivo and utilized an in vitro model of the erythroid differentiation of murine erythroleukemia cells (MEL) to evaluate the effect of silencing PrPC through RNA interference. The expression of PrPC and selected differentiation markers was analyzed by quantitative multicolor flow cytometry, western blot analysis and quantitative RT-PCR. The silencing of PrPC expression in MEL cells was achieved by expression of shRNAmir from an integrated retroviral vector genome. The initial upregulation of PrPC expression in differentiating erythroid precursors was detected both in vivo and in vitro, suggesting PrPC's importance to the early stages of differentiation. The upregulation was highest on early erythroblasts (16200±3700 PrPC / cell) and was followed by the gradual decrease of PrPC level with the precursor's maturation reaching 470±230 PrPC / cell on most mature CD71-Ter119+ small precursors. Interestingly, the downregulation of PrPC protein with maturation of MEL cells was not accompanied by the decrease of PrP mRNA. The stable expression of anti-Prnp shRNAmir in MEL cells led to the efficient (>80%) silencing of PrPC levels. Cell growth, viability, hemoglobin production and the transcription of selected differentiation markers were not affected by the downregulation of PrPC. In conclusion, the regulation of PrPC expression in differentiating MEL cells mimics the pattern detected on mouse erythroid precursors in vivo. Decrease of PrPC protein expression during MEL cell maturation is not regulated on transcriptional level. The efficient silencing of PrPC levels, despite not affecting MEL cell differentiation, enables created MEL lines to be used for studies of PrPC cellular function.
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