Diverse spatial expression patterns of UDP-GalNAc:polypeptide N-acetylgalactosaminyl-transferase family member mRNAs during mouse development.

Cell migration and adhesion during embryonic development are complex processes which likely involve interactions among cell-surface carbohydrates. While considerable work has implicated proteoglycans in a wide range of developmental events, only limited attention has been directed towards understanding the 7role(s) played by the related class of mucin-type O-glycans. The initial step of mammalian mucin-type O-glycosylation is catalyzed by a family of UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferases (ppGaNTases). The spatial expression patterns of the messenger RNAs of seven ppGaNTase family members were investigated from gastrulation through organogenesis stages of mouse development. The seven glycosyltransferases were expressed in unique patterns during embryogenesis. ppGaNTase-T1, -T2, -T4, and -T9 were expressed more ubiquitously than ppGaNTase-T3, -T5, and -T7. Organ systems with discrete accumulation patterns of ppGaNTase family members include the gastrointestinal tract (intestine, liver, stomach, submandibular gland), nervous system (brain, eye), lung, bone, yolk sac, and developing craniofacial region. The pattern in the craniofacial region included differential expression by family members in developing mandible, teeth, tongue and discrete regions of the brain including the pons and migratory, differentiating neurons. Additionally, ppGaNTase-T5 accumulates in a subset of mesenchymal cells at the ventral-most portions of the E12.5 maxilla and mandible underlying the dental lamina. The unique spatiotemporal expression of the different ppGaNTase family members during development suggests unique roles for each of these gene products.