Distinct pathways regulated by menin and by MLL1 in hematopoietic stem cells and developing B cells

作者：Li Bin E; Gan Tao; Meyerson Matthew; Rabbitts Terence H; Ernst Patricia^*

来源：Blood, 2013, 122(12): 2039-2046.

DOI：10.1182/blood-2013-03-486647

Mixed Lineage Leukemia (MLL1) translocations encode fusion proteins retaining the N terminus of MLL1, which interacts with the tumor suppressor, menin. This interaction is essential for leukemogenesis and thus is a promising drugtarget. However, wild-type MLL1 plays a critical role in sustaining hematopoietic stem cells (HSCs); therefore, disruption of an essential MLL1 cofactor would be expected to obliterate normal hematopoiesis. Here we show that rather than working together as a complex, menin and MLL1 regulate distinct pathways during normal hematopoiesis, particularly in HSCs and B cells. We demonstrate the lack of genetic interaction between menin and MLL1 in steady-state or regenerative hematopoiesis and in B-cell differentiation despite the fact that MLL1 is critical for these processes. In B cells, menin-or MLL1-regulated genes can be classified into 3 categories: (1) a relatively small group of coregulated genes including previously described targets Hoxa9 and Meis1 but also Mecom and Eya1, and much larger groups of (2) exclusively menin-regulated and (3) exclusively MLL1-regulated genes. Our results highlight the large degree of independence of these 2 proteins and demonstrate that menin is not a requisite cofactor for MLL1 during normal hematopoiesis. Furthermore, our data support the development of menin-MLL1-disrupting drugs as safe and selective leukemia targeting agents.

• 出版日期2013-9-19