Golgb1 Regulates Protein Glycosylation in Mouse Palate Development

Objectives: Cleft palate is a common major birth defect for which currently known causes account for less than 30% of pathology in humans. Through a phenotype-driven genetic screen in mice in combination with whole exome sequencing, we identified a mutation in the Golgb1 gene as a candidate cause of cleft palate. The objectives of this study are to validate that loss of Golgb1 function caused cleft palate and to unravel the molecular mechanisms involving Golgb1 in palate development.
Methods: We generated mice carrying independent loss-of-function Golgb1 alleles using CRISPR/Cas9-mediated genome editing. We used histological and immunofluorescent staining assays to characterize the palatal developmental defects. We used lectin-staining assays to reveal defects in glycosylation.
Results: We found that mice homozygous or transheterozygous for distinct frame-shift mutations in Golgb1 exhibit cleft palate. Histological analysis showed that Golgb1 mutant embryos have failure of palatal shelf elevation. Interestingly, just prior to the developmental stage of normal palatal shelf elevation, the Golgb-deficient mouse embryos exhibit reduced hyaluronan accumulation and increased cell density in the palatal mesenchyme. Lectin staining revealed that Golgb1 mutant palatal mesenchyme exhibit significantly increased binding to VVA, PNA and GSII lectins, indicating disruption of protein glycosylation.
Conclusions: Although Golgb1 is ubiquitously expressed, it plays specific roles in regulation protein glycosylation during palate development.