Phase separation of CTD of RNAPII

The carboxy-terminal domain (CTD) of the largest subunit of RNA Polymerase II (RNAPII) consists of multiple tandem repeats of the heptapeptide consensus Y1-S2-P3-T4-S5-P6-S7. RNAPII CTD is intrinsically disordered and has been shown to promote liquid-liquid phase-separation (LLPS) of RNAPII in vivo. However, understanding the precise role of the conserved heptad residues in LLPS has been hampered by the lack of direct characterization of the biochemical properties of the CTD. Here, we generated a systematic array of RNAPII CTD variants to unravel the sequence-encoded molecular grammar underlying LLPS of the human CTD.