Schematics of RUNX1 fusion proteins. (A) Schematic diagram of full-length RUNX1-CBFA2T1, illustrating the site of fusion between the 2 proteins. RUNX1-CBFA2T1 comprises the RHD from RUNX1 and 4 Nervy homology regions (NHR1–4) from CBFA2T1. The location of the nuclear localization signal (NLS) is also indicated. (B) Schematic diagram of ETV6-RUNX1, illustrating the site of fusion between the 2 proteins. The ETV6-RUNX1 fusion protein contains the N-terminal non-DNA binding moiety of ETV6 fused to almost the entire RUNX1 protein, including its RHD and TAD domains, and the VWRPY motif. (C) Schematic diagram of RUNX1-MECOM, illustrating the site of fusion between the 2 proteins. In the RUNX1-MECOM fusion, RUNX1 fuses with one or both of the “MDS1 and EVI1 complex locus” genes present at chromosome 3q26.