EOGT enables residual Notch signaling in mouse intestinal cells lacking POFUT1

Area of Science:

• Developmental Biology
• Glycobiology
• Cell Signaling

Background:

• Notch signaling is essential for cell fate determination in the mouse intestine.
• O-glycans on Notch receptors regulate signaling, with protein O-fucosyltransferase 1 (Pofut1) playing a key role.
• Conditional Pofut1 deletion in the intestine reduces Notch signaling but allows survival, unlike complete Notch pathway elimination.

Purpose of the Study:

• To investigate the role of EGF-domain-specific O-linked N-acetylglucosamine transferase (Eogt) in compensating for Pofut1 loss in intestinal Notch signaling.
• To determine if residual Notch signaling mediated by Eogt supports the survival of mice lacking Pofut1 in the intestine.

Main Methods:

• Conditional gene deletion of Pofut1 and Eogt in mouse intestine.
• Analysis of intestinal development, cell lineage composition (goblet, Paneth cells), and Notch target gene expression (Hes1).
• Assessment of body weight and survival rates in genetically modified mice.

Main Results:

• Global Eogt deletion alone did not significantly affect intestinal development.
• Mice lacking both Pofut1 and Eogt exhibited reduced survival, greater weight loss, increased goblet and Paneth cells, and Hes1 downregulation compared to Pofut1-deficient mice.
• Residual Notch signaling, supported by Eogt and O-GlcNAc glycans, is critical for intestinal viability when Pofut1 is absent.

Conclusions:

• Both O-fucose and O-GlcNAc glycans are fundamental for Notch signaling in the mouse intestine.
• EOGT-mediated O-GlcNAc glycosylation provides essential residual Notch signaling, supporting viability in Pofut1-deficient mice.
• These findings offer new insights into the regulatory roles of O-glycans in Notch ligand binding and signaling.