Identification of PCBP as part of the ribonucleoprotein complex associated with EPO HIPBS-like element in HepG2 cells Proteins electroeluted from the EPO DdeI transcript-associated complexes were analyzed by Western blot technique. The same membrane was first probed with specific anti-PCBP₁ antibody,and then stripped and reprobed with anti-PCBP₂ antibody. The lower complex (corresponding to the TH-HIPBS–associated complex) contains both isoforms of PCBP (lane 5), which is absent in the eluates from gel slices containing binding reaction without RNA (lane 4) or in the upper complex (lanes 2 and 3). Lane 1, 100 μg of HepG2 protein extract.