Post-translational modifications (PTMs) have been gradually elucidated in congenital malformations such as cleft palate. Among them, O-GlcNAcylation as a dynamic PTM of proteins regulates various critical biological processes including transcription, translation, and cell fate determination. In this study, a substantial decline in O-linked β-D-N-acetylglucosamine (O-GlcNAc) levels was detected within the palatine plates of all-trans retinoic acid (atRA)-induced cleft palate mice. The role of O-GlcNAc transferase (OGT), the sole enzyme responsible for catalyzing O-GlcNAcylation, was investigated in the process of palatal development. In a zebrafish model, the loss of O-GlcNAc resulted in an elevated prevalence of cleft palate and compromised palatal bone formation. Mechanistically, O-GlcNAcylation of myeloid ecotropic viral integration site 2 (MEIS2), which is mediated by OGT, was found to maintain osteogenic homeostasis by modulating its protein stability through inhibition of ubiquitination. Notably, the serine 237 residue (Ser237) was identified as a critical site for MEIS2 O-GlcNAcylation. Together, the present study uncovers the important function of MEIS2 O-GlcNAcylation in palatal bone development and establishes a novel theoretical framework for understanding the regulatory network of palatal development. This finding may provide novel avenues for the future diagnosis and prevention of cleft palate.
Zhang et al. (Sun,) studied this question.