Synergistic Regulation of Notch Signaling by Different O-Glycans Promotes Hematopoiesis

Abstract

Glycosylation of Notch receptors by O-fucose glycans regulates Notch ligand binding and Notch signaling during hematopoiesis. However, roles in hematopoiesis for other O-glycans that modify Notch receptors have not been determined. Here we show that the EGF domain-specific GlcNAc transferase EOGT is required in mice for the optimal production of lymphoid and myeloid cells. The phenotype of Eogt null mice was largely cell-autonomous, and Notch target gene expression was reduced in T cell progenitors. Moreover, EOGT supported residual Notch signaling following conditional deletion of Pofut1 in hematopoietic stem cells (HSC). Eogt:Pofut1 double mutant HSC had more severe defects in bone marrow, and in T and B cell development in thymus and spleen, compared to deletion of Pofut1 alone. The combined results show that EOGT and O-GlcNAc glycans are required for optimal hematopoiesis and T and B cell development, and that they act synergistically with POFUT1 and O-fucose glycans to promote Notch signaling in lymphoid and myeloid differentiation. Key pointsO_LIO-GlcNAc glycans and EOGT promote lymphopoiesis and myelopoiesis C_LIO_LIEOGT supports Notch signaling in the absence of POFUT1 and O-fucose glycans C_LI