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Fig. 7 Interactions between zebrafish PRC1 components. (A) GST pull down experiments showing that Bm1a and Bmi1b directly interact with Rnf2 and the isoforms Cbx4a1, Cbx4a2 and Phc2a2, and showing that Rnf2 directly interacts with Cbx4a1, Phc2a2 and Bmi1a, but not with the Cbx4 isoform lacking the Pc box, Cbx4a2. GST-tagged Bmi1a, Bmi1b, Rnf2 and GFP as a control were expressed in E. coli, bound to glutathione-Sepharose, and incubated with in vitro expressed TAP-tagged Cbx4a1, Cbx4a2, Phc2a2, Rnf2 or Bmi1a proteins, as indicated. After washing, proteins were separated by SDS-PAGE and Western blots probed with peroxidase anti-peroxidase (αPAP) antibodies to reveal TAP-tagged proteins. (B) The Cbx Pc box is required for direct interaction with Rnf2, but not required for Cbx interactions with Phc2a2 and Bmi1a. GST-tagged Cbx4a1, Cbx4a2, Cbx8a, Cbx8b, Cbx6a1, Cbx7a and GFP as a control were expressed in E. coli, bound to glutathione-Sepharose, and incubated with in vitro expressed TAP-tagged Bmi1a, Phc2a2 or Rnf2 proteins, as indicated and Western blots performed as indicated in (A). (C) Schematic representation of interactions between zebrafish PRC1 components in vitro. The dashed line indicates that the interaction occurs with Pc box-containing Cbx isoforms, but not with Cbx isoforms lacking the Pc box.
Reprinted from Gene, 475(1), Le Faou, P., Völkel, P., and Angrand, P.O., The zebrafish genes encoding the Polycomb Repressive Complex (PRC) 1, 10-21, Copyright (2011) with permission from Elsevier. Full text @ Gene