MX1 and myeloproliferative disorder: When Mindbomb-1 (Mib1), an essential gene for Notch ligand endocytosis, was deleted (Mx1-cre; Mib1−/− mice or MMTV-cre, Mib1−/−1 mice), the mice developed de novo myeloproliferative neoplasm (MPN), which is attributable to the loss of Mib1 from the bone marrow microenvironment (Kim et al., 2008).