The identification of the 8F1 cross-reactive protein with protein microarray chip and Western blot confirmation. A. Protein microarray hybridization with 8F1. The OriGene overexpression protein microarray chip was immunostained with the most commonly used 8F1 monoclonal anti-ERCC1 antibody. The positive reactive proteins are highlighted with red arrows. These data show that 8F1 recognizes not only its specific target (two ERCC1 transcript variants), but also another unrelated nuclear membrane protein PCYT1A. A number of internal controls were also labeled on the panel. B. Western Blot analysis. Seven OriGene VERIFY™ overexpression lysate antigen standards (Lane 1 to 7) were fractionated on SDS-PAGE, and then immunoblotted with 8F1 (Upper panel). The recombinant protein expression levels within the lysates were analyzed with anti-DDK antibody (Lower panel). Lanes 1 to 7 are loaded with samples for ERCC1 (NM_202001), ERCC1 (NM_001983), ERCC2 (NM_000400), ERCC3 (NM_000122), ERCC4 (NM_005236), ERCC5 (NM_000123) and PCYT1A (NM_005017).