Protein arginine methyltransferase 5 is a key regulator of the MYCN oncoprotein in neuroblastoma cells.
Bottom Line: Immunoblotting of NB cell-lines shows that high PRMT5 expression is strongly associated with MYCN-amplification (P < 0.004, Mann-Whitney U-test) and immunohistochemical analysis of primary NBs reveals that whilst PRMT5 protein is ubiquitously expressed in the cytoplasm of most cells, MYCN-amplified tumours exhibit pronounced nuclear PRMT5 staining.PRMT5 knockdown in MYCN-overexpressing cells, including the SHEP-21N cell-line with inducible MYCN expression leads to a dramatic decrease in MYCN protein and MYCN-associated cell-death in SHEP-21N cells.Together our studies implicate PRMT5 in a novel mode of MYCN post-translational regulation and suggest PRMT5 plays a major role in NB tumorigenesis.
Affiliation: Cancer Epigenetics Laboratory University of Bristol, Bristol BS8 1TD, UK.Show MeSH
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Mentions: We next sought to establish whether endogenous PRMT5 physically associated with MYCN complexes in NGP and SK-N-BE(2)C cells, as such an interaction may serve to stabilise MYCN and provide initial evidence that MYCN might be a substrate for the arginine methyltransferase activity of PRMT5. As shown in Figure 7A, MYCN was easily detected in PRMT5 complexes immunoprecipitated from NGP extracts and PRMT5 was also confirmed in the reciprocal MYCN immunoprecipitation. This robust interaction was also apparent in SK-N-BE(2)C cells (Figure 7B), and is consistent with the notion that PRMT5 is capable of stabilizing MYCN at the protein level.
Affiliation: Cancer Epigenetics Laboratory University of Bristol, Bristol BS8 1TD, UK.