nucleolus

BMH-21, a small molecule DNA intercalator, binds ribosomal DNA and inhibits RNA polymerase I (Pol I) transcription and not affects phosphorylation of H2AX.

Pidnarulex HCl is the salt form of CX-5461, a first-in-class non-genotoxic small molecule targeted inhibitor of RNA polymerase I (Pol I) that activates the p53 pathway without causing DNA damage. CX-5461 selectively inhibits rRNA synthesis by Pol I in the nucleolus, but does not inhibit mRNA synthesis by RNA Polymerase II (Pol II) and does not inhibit DNA replication or protein synthesis. Inhibition of Pol I results in nucleolar stress and release of ribosomal proteins (RP) from the nucleolus. The RP bind to Mdm2 and liberate p53 to orchestrate apoptosis in cancer cells. CX-5461 demonstrates a favorable preclinical profile, potently and selectively kills cancer cells, demonstrates robust in vivo efficacy in multiple models, and has demonstrated oral bioavailability in multiple species.

Diazaborine inhibits maturation of rRNAs for the large ribosomal subunit. Diazaborine blocks ribosome biogenesis by inhibiting the AAA-ATPase Drg1. Diazaborine treatment causes, within minutes, a rapid redistribution of the protein from the nucleolus to t