Over the last 10 years, great progress has been made in identifying the genetic alterations present in the blood systems of patients with myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). One of the most important and unexpected findings from these studies has been the identification of mutations in genes which perform RNA splicing. Mutations in these genes are the single most frequent category of mutations seen in MDS patients but are currently not well understood. Under normal conditions, RNA splicing is responsible for ‘processing’ RNA so that the genetic code can be effectively translated to produce normal proteins. It has been postulated that mutations in this pathway impair RNA splicing. However, how precisely these mutations dysregulate splicing and how this actually results in the development of leukemia is unknown. More importantly, how this genetic knowledge can be translated to yield novel drug targets in leukemia has yet to be investigated. The protein SRSF2 is particularly important, since it is associated with the most clinically dangerous forms of MDS and AML. We have recently generated a number of mouse and human cell leukemia models with and without mutations in SRSF2. We now propose to utilize these models to understand how mutations in SRSF2 cause leukemia and how we can treat the leukemia caused by these mutations.