Fig 1: Pol II partitioning in transcriptional and splicing factor condensatesa. First four rows: IF imaging using antibodies for the hypophosphorylated and serine 2 phosphorylated (S2P) Pol II CTD, coupled with IF for MED1 or direct visualization of SRSF2 in the GFP-SRSF2 mESCs. Last two rows: IF for SRSF2 coupled to IF for HP1a or direct visualization of SRSF2 in the GFP-SRSF2 mESCs. The “Co-loc” column highlights overlapped pixels for each factor in an example z-slice, and the Manders’ overlap coefficient gives a relative score for the degree of overlap from multiple cells and images (see methods). For each experimental comparison, one coverslip of cells was stained for the indicated factors and 5 independent fields were imaged and analyzed.b. Top: Representative ChIP-seq tracks of MED1, SRSF2 and the hypophosphorylated or serine 2 phosphorylated forms of Pol II in mESCs. Y-axis in reads per million (RPM). Bottom: Metagene plots of average ChIP-seq RPM for the same factors across gene bodies (see methods). ChIP-seq was performed once for each factor with approximately 100 million cells.c. Representative images exhibiting overlap or lack of overlap between IF of SRSF2 and DNA FISH of Nanog in mESCs treated with DMSO for 2 hrs, DRB for 2 hrs, or DRB for 2 hrs followed by a 2 hr washout.d. Representative images exhibiting overlap between IF of MED1 and DNA FISH of Nanog in mESCs treated as in panel c.