SF3B1 hotspot mutations are neomorphic and induce aberrant 3′ splice site selection

Mutant SF3B1 utilizes a different branch point than that used by wild-type SF3B1

SF3B1 mutants require the canonical 3′ splice site to induce aberrant splicing

∼50% of aberrant mRNAs undergo NMD leading to downregulation of canonical isoforms