The tetramer structure of the Nervy homology two domain, NHR2, is critical for AML1/ETOʹs activity

Summary TO is the chimeric protein resulting from the t(8;21) in acute myeloid leukemia. The Nervy homology 2 (NHR2) domain in ETO mediates oligomerization and AML1/ETOʹs interactions with ETO, MTGR1, and MTG16, and with the corepressor molecules mSin3A and HDAC1 and HDAC3. We solved the NHR2 domain structure and found it to be an α-helical tetramer. We show that oligomerization contributes to AML1/ETOʹs inhibition of granulocyte differentiation, is essential for its ability to enhance the clonogenic potential of primary mouse bone marrow cells, and affects AML1/ETOʹs activity on several endogenous genes. Oligomerization is also required for AML1/ETOʹs interactions with ETO, MTGR1, and MTG16, but not with other corepressor molecules.