RNA polymerase II transcription machinery (RNAPII)

The RNA polymerase II (Pol II) transcription machinery is a sophisticated multi-protein assembly responsible for the synthesis of messenger RNA (mRNA) and most small nuclear RNAs in eukaryotic cells (UniProt, 2023). At its core is the 12-subunit RNA polymerase II enzyme, which works in concert with general transcription factors (GTFs) such as TFIID and TFIIH, as well as the Mediator complex, to initiate, elongate, and terminate transcription (Nature Reviews Molecular Cell Biology, 2020). This machinery serves as a central hub for gene regulation, integrating various cellular signals to control growth, differentiation, and stress responses. In many malignancies, the Pol II machinery is hyperactivated or hijacked to drive the expression of potent oncogenes like MYC, a phenomenon often described as transcriptional addiction (Cell, 2018). Therapeutic interventions targeting this machinery include direct inhibitors like Lurbinectedin, which induces the degradation of the RPB1 subunit, and inhibitors of associated kinases like CDK7 and CDK9 that regulate the transcription cycle (FDA, 2020; Trends in Pharmacological Sciences, 2019). While highly effective in certain contexts, targeting the Pol II machinery presents significant challenges due to its fundamental role in all living cells, requiring precise dosing to achieve a therapeutic index.

Other names

RNA polymerase II complexPol II holoenzymeDNA-directed RNA polymerase IIPre-initiation complexRNAP II

Inhibition of the catalytic activity of RNA polymerase II, degradation of the RPB1 subunit, or inhibition of regulatory kinases (such as CDK7 and CDK9) that control the transcription cycle stages including initiation, pausing, and elongation (Nature Reviews Molecular Cell Biology, 2020; PubMed, 2021).