Structurally diverse low molecular weight activators of the mammalian pre-mRNA 3′ cleavage reaction

The 3′ end formation of mammalian pre-mRNA contributes to gene expression regulation by setting the downstream boundary of the 3′ untranslated region, which in many genes carries regulatory sequences. A large number of protein cleavage factors participate in this pre-mRNA processing step, but chemical tools to manipulate this process are lacking. Guided by a hypothesis that a PPM1 family phosphatase negatively regulates the 3′ cleavage reaction, we have found a variety of new small molecule activators of the in vitro reconstituted pre-mRNA 3′ cleavage reaction. New activators include a cyclic peptide PPM1D inhibitor, a dipeptide with modifications common to histone tails, abscisic acid and an improved l-arginine β-naphthylamide analog. The minimal concentration required for in vitro cleavage has been improved from 200 μM to the 200 nM-100 μM range. These compounds provide unexpected leads in the search for small molecule tools able to affect pre-mRNA 3′ end formation.