Fig. 6: PSPC1 co-condensates with NONO-TFE3 and RNAPII on chromatin.

a, b The LacI-LacO array for multivalent heterotypic interaction detection between NONO-TFE3 truncations and PSPC1 or RNAPII C-terminal domain (Pol2 CTD) on genomic loci (a). NONO-TFE3 truncates-LacI are labeled with GFP, and PSPC1 or Pol2 CTD are labeled with mCherry. The LacO array locus is circled and zoom-in LacO array locus images are shown (white box). The quantifications of enrichment (b) were performed with 6 cells from 3 independent biological replicates. (one-way ANOVA with Tukey’s post-hoc test). Scale bar, 10 µm. Data are shown as mean ± SD. c Representative images of in vitro droplets formed by mCherry-fused NONO-TFE3, BFP-fused RNAPII CTD, and GFP-fused PSPC1 with the indicated concentrations of RNA. GFP alone was used as control. Scale bar, 10 µm. d Quantifications of droplet area (top) and co-condensation efficiency (bottom) from in vitro droplet formation assay shown in (c). (n = 30 droplets from 3 independent biological replicates; two-sided unpaired Student’s t-test). Data are shown as mean ± SD. e Schematic illustration of the droplet sedimentation assay (top) and immunoblotting of CTD incorporation in droplets (bottom). n = 3 independent biological replicates. Created in Created in BioRender. Suris, A. (https://BioRender.com/zwfnjs8). Source data are provided as a Source Data file.