U2AF1 and myelodysplastic syndrome: As the most common mouse model for the mutant allele of the U2AF1 mutation, the genetically engineered mice that assemble U2af1S34F generated by Cre recombinase exhibit impaired hematopoiesis with MDS-like features (multilineage cytopenia and dysplasia), as well as aberrant splicing profiles similar to the splicing alterations in U2AF1S34F mutated human cells [55].