PT  - JOURNAL ARTICLE
AU  - Rakesh Chatrikhi
AU  - Callen F. Feeney
AU  - Mary J. Pulvino
AU  - Georgios Alachouzos
AU  - Andrew J. MacRae
AU  - Zackary Falls
AU  - Sumit Rai
AU  - William W. Brennessel
AU  - Jermaine L. Jenkins
AU  - Matthew J. Walter
AU  - Timothy A. Graubert
AU  - Ram Samudrala
AU  - Melissa S. Jurica
AU  - Alison J. Frontier
AU  - Clara L. Kielkopf
TI  - A synthetic small molecule stalls pre-mRNA splicing by promoting an early-stage U2AF2–RNA complex
AID  - 10.1101/2020.09.28.317727
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.09.28.317727
4099  - http://biorxiv.org/content/early/2020/10/23/2020.09.28.317727.short
4100  - http://biorxiv.org/content/early/2020/10/23/2020.09.28.317727.full
AB  - Dysregulated pre-mRNA splicing is an emerging Achilles heel of cancers and myelodysplasias. To expand the currently limited portfolio of small molecule drug leads, we screened for chemical modulators of the U2AF complex, which nucleates spliceosome assembly and is mutated in myelodysplasias. A hit compound specifically enhances RNA binding by a U2AF2 subunit. Remarkably, the compound inhibits splicing of representative substrates in cells and stalls spliceosome assembly at the stage of U2AF function. Computational docking, together with structure-guided mutagenesis, indicates that the compound bridges an active conformation of the U2AF2 RNA recognition motifs via hydrophobic and electrostatic moieties. Altogether, our results highlight the potential of trapping early spliceosome assembly as an effective pharmacological means to manipulate pre-mRNA splicing. By extension, we suggest that stabilizing inactive checkpoints may offer a breakthrough approach for small molecule inhibition of multi-stage macromolecular assemblies.Competing Interest StatementThe authors have declared no competing interest.