Fig. 4: Interaction between the PRC1 catalytic core and the nucleosome is not a central determinant of chromatin binding.

a A schematic illustrating the cell line used for exogenous expression of RING1B-HaloTag fusions. Either wild type (WT) RING1B or a nucleosome binding mutant (NBM) fused to the HaloTag was stably expressed in Ring1a^-/-; Ring1b^fl/fl (PRC1^CKO) cells. Addition of OHT causes removal of endogenous RING1B. b Western blots showing loss of endogenous RING1B and H2AK119ub1 following addition of OHT in PRC1^CKO cells and rescue of H2AK119ub1 by RING1B-HaloTag but not RING1B^NBM-HaloTag. TBP and H3 are included as loading controls. n = 1 biological replicate. Source data are provided as a Source Data file. c A box plot indicating the percentage of RING1B and RING1B^NBM molecules in the bound state as determined by SPT. Box plots represent measurements from n > 90 movies of different cells from 3 experiments. The indicated p-value was calculated using a two-tailed Student’s t test. Source data are provided as a Source Data file. d A box plot showing the fraction of RING1B and RING1B^NBM molecules that exhibit stable binding. Box plots represent measurements from n = 16 movies from 2 experiments. The indicated p-value was calculated using a two-tailed Student’s t test. e. Schematic showing the minimal RING1B PCGF4 catalytic domain (RPCD) formed by fusion of the RING domains of RING1B and PCGF4. Source data are provided as a Source Data file. f A box plot of percentages of RING1B and RPCD molecules in the bound state. Box plots represent measurements from n > 90 movies from 3 experiments. The indicated p value was calculated using a two-tailed Student’s t test. Source data are provided as a Source Data file. In c, d, f boxes represent the interquartile range (IQR), the middle line corresponds to the median, and whiskers extend to the largest and smallest values no more than 1.5 x IQR from the box. Values outside of this range are not plotted, but are included in all analyses.