Expression analysis of transformed Arabidopsis lines. Protein extracts (20 μg) from wild type (WT) and different independent Arabidopsis transgenic lines transformed with pH2n-H2A (A), pH2c-H2A (B), pH2n-UBI (C), pE5n-UBI (D) were separated on 15% SDS-PAGE and analysed by western blotting using antibodies against HA (A-C) or GFP (D). Ponceau staining is shown as loading control below each panel. E, Protein extracts from wild type (WT) and an Arabidopsis transgenic line expressing Strep-Ubiquitin were used for affinity purification on a Streptactin resin. Bound proteins were resolved on 15% SDS-PAGE and analysed by western blotting using an antibody against the STREP epitope. Ponceau staining at the bottom shows the presence of streptactin in both samples.