Plasmid construction and establishment of DBT stable cell lines The cDNA of the murine hnRNP A1 gene was ampli®ed by RT±PCR using RNA extracted from DBT cells and a set of primers representing the 5¢-and 3¢-ends of hnRNP A1-coding region, and cloned into pcDNA3.1 (Invitrogen, Carlsbad, CA). The 8 amino acid Flag tag was attached to the N-terminus of hnRNP A1 by including the Flag tag in the forward PCR primer. The truncated hnRNP A1DC was similarly constructed using a PCR-ampli®ed fragment that represents hnRNP A1 (aa 1±245).