Detection of YB-1-GFP and YB-1(21-147)-GFP by immunoblot and recombinant YB-1 by ELISA. (A) HEK293T cell extracts containing GFP (lanes 1 and 4), YB-1-GFP (lane 2, 5 and 7) or YB-1(21-147)-GFP proteins (lanes 3, 6 and 8) were separated in denaturing gels and following transfer to nitrocellulose probed with GFP antibody (lanes 1 to 3) or Mab F-E2G5 (lanes 4 to 8). Relative mobilities of expressed proteins are indicated by arrowheads. Notably, reducing sample buffer prevents detection of tagged YB-1 proteins by immunoblot (lanes 7 and 8). (B) ELISA was performed by coating with recombinant affinity purified hexahistidin-tagged YB-1 protein. Biotin-labeled Mab F-E2G5 yields an even stronger signal than non-biotinylated Mab. Controls included omission of antibody (Con1) or antigen (Con2).