Host transcriptional machinery (HTM)

The host transcriptional machinery is a sophisticated multi-protein assembly, primarily centered around RNA polymerase II (Pol II) and its associated general transcription factors and regulatory kinases, such as CDK9 and CDK7 [Young, 2011; Nature Reviews Genetics]. This machinery is responsible for the synthesis of messenger RNA (mRNA) from DNA templates, a fundamental process for cellular life. In the context of infectious diseases, many viruses, particularly DNA viruses and retroviruses like HIV, hijack this host apparatus to transcribe their own genomes [Ott et al., 2011; Trends in Microbiology]. In oncology, malignant cells often develop a "transcriptional addiction," where they become disproportionately dependent on the continuous expression of short-lived oncogenic drivers like MYC and anti-apoptotic factors like MCL1 to maintain their phenotype [Bradner et al., 2017; Cell]. Therapeutic agents such as Alvocidib (Flavopiridol) and Lurbinectedin target components of this machinery, such as the Positive Transcription Elongation Factor b (P-TEFb) or Pol II itself, to induce rapid depletion of these critical proteins [Garrido-Laguna et al., 2018; Nature Reviews Clinical Oncology]. However, because these processes are essential for normal cell function, drugs targeting the host transcriptional machinery often carry risks of systemic toxicity and require careful dosing to achieve a therapeutic window [Wang and Fischer, 2008; Trends in Pharmacological Sciences].

Other names

Host cell transcription apparatusHost transcription systemRNA polymerase II complexHost gene expression machinery

Inhibition of RNA polymerase II activity, blockade of transcriptional elongation via CDK9/P-TEFb inhibition, or DNA intercalation to prevent polymerase progression [PubMed; Nature Reviews Drug Discovery].