Untransfected and U2OS stably expressing Flag-DDX5 WT or Flag-DDX5-RK were subjected to immunoprecipitation with anti-Flag antibody. The WCE and the anti-Flag immunoprecipitated proteins were Western blotted with anti-monomethylarginine (MeR), anti-Flag and anti-XRN2 antibodies, respectively. M denotes molecular mass markers in kDa. 