RNA splicing is a biological process to generate mature mRNA (mRNA) by removing introns and annexing exons in the nascent RNA transcript and is executed by a multiprotein complex called spliceosome. To aid RNA splicing, a class of splicing factors use an atypical RNA recognition domain (UHM) to bind with U2AF ligand motifs (ULMs) in proteins to form modules that recognize splice sites and splicing regulatory elements on mRNA. Mutations of UHM containing splicing factors have been found frequently in myeloid neoplasms. To profile the selectivity of UHMs for inhibitor development, we established binding assays to measure the binding activities between UHM domains and ULM peptides and a set of small-molecule inhibitors. Additionally, we computationally analyzed the targeting potential of the UHM domains by small-molecule inhibitors. Our study provided the binding assessment of UHM domains to diverse ligands that may guide development of selective UHM domain inhibitors in the future.

Scheme 1. General Synthetic Scheme to Prepare UHMCP1 and Analogs a a Reagents and conditions: (a) secondary amine, Ti(OiPr) 4 , THF, 65 °C; (b) NaBH(OAc) 3 , CH 3 OH, r.t.; (c) 4 M HCl in dioxane, r.t.; (d) LiOH, CH 3 OH/THF/H 2 O, r.t. *: Chiral center.