Fig. 1. Endogenous Halo-tagging of RING1B enables live-cell imaging of PRC1.

a A schematic illustrating the general organisation of PRC1 complexes. b Western blots for RING1B (upper panels) and H2AK119ub1 (lower panels) comparing wild type (WT) and homozygous RING1B-HaloTag (RING1B-HT) cell lines. The expected size shift on addition of the HaloTag and linker is 35 kDa. TBP and H3 were used as loading controls. n = 1 biological replicate. Source data are provided as a Source Data file. c Immunoprecipitation (IP) of RING1B from WT or RING1B-HT ESCs followed by western blotting for PRC1 subunits to confirm normal complex formation. For WT ESCs, a control IP was performed using a FLAG antibody. n = 1 biological replicate. Source data are provided as a Source Data file. d Representative single Z-slice of untagged (WT) and RING1B-HT ESCs labelled with JF₅₄₉ and Hoechst. Scale bar = 5 μm. Imaging was performed in n = 2 biological replicates.