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: In order to assess PRMT5 influence on post-translational MYCN stability, we conducted cycloheximide chase assays on PRMT5 siRNA transfected cells. As shown in Figure 5A-B, MYCN is turned over with a half-life of approximately 90 min in NGP cells transfected with negative control siRNA, but the half-life is dramatically decreased to approximately 22 min in cells transfected with PRMT5 siRNA. Similarly, in induced SHEP-Tet21N cells, MYCN protein exhibits a half-life of approximately 46 min, which is reduced to approximately 18 min after PRMT5 knockdown.
Affiliation: Cancer Epigenetics Laboratory University of Bristol, Bristol BS8 1TD, UK.