RNA polymerase II (Pol II) is an enzyme that is composed of twelve subunits and is responsible for the transcription of protein-coding genes. Transcription initiation requires Pol II-mediated recruitment of transcription machinery to a target promoter, thereby allowing transcription to begin. The integrator complex is a multi-protein complex that associates with the C-terminal domain of Pol II and is involved in small nuclear RNA (snRNA) transcription and 3’-end processing. This interaction is facilitated by phosphorylation of serine-7 on Pol II. CPSF3L (Cleavage and polyadenylation-specific factor 3-like protein), also known as Integrator complex subunit 11 (INTS11), is a 600 amino acid protein that is a component of the integrator complex and is expressed as three isoforms.
