Figure 3. Both USP21SV and USP21LV deubiquitylate ubH2A and activate transcription.

A) Deubiquitylation assay. Different amounts of recombinant USP21SV and USP21LV were incubated with native chromatin as indicated. Signals from ubH2A were detected by Western blotting using anti-ubH2A and Alexa 647-Protein A (Life Technologies). Amido black staining was used as loading control. B) Native H3-H4 and ubH2A-H2B were purified from mouse liver. C) Chromatin was assembled by salt dialysis and digested with micrococcal nuclease. D) Ubiquitylated chromatin was subjected to transcription after treatment with USP21-SV, USP21-LV or control buffer as indicated. Deubiquitylated H2A was confirmed by Western blotting with anti ubH2A. Transcripts were detected by primer extension.