O-GlcNAc characterization during Tribolium castaneumdevelopment

O-GlcNAc (O-linked β-N-acetylglucosamine) is a dynamic intracellular post-translational modification (PTM) that regulates several cellular processes. This PTM is catalyzed by the covalent attachment of GlcNAc on residues of serine/threonine in proteins by the enzyme O-GlcNAc transferase (OGT), while its removal is performed by O-GlcNAcase (OGA). This PTM is limited by the concentration of UDP-GlcNAc, the end-product from the hexosamine biosynthetic pathway (HBP) that, together with OGT and OGA levels and activity, will regulate protein O-GlcNAcylation. Although O-GlcNAc has been reported in all studied metazoans, functional analysis during development in Hexapoda is restricted to the model organism Drosophila melanogaster. In this study, the role of O-GlcNAc during development was investigated in an emerging model system, the beetle Tribolium castaneum. Comparison of the transcriptional profile of the HBP rate-limiting step enzyme glutamine-6-phosphate amidotransferase (GFAT) during developmental stages showed higher levels during larval stages. Interestingly, OGT is modulated during embryonic development with an increase of mRNA levels during gastrulation while OGA remained unaltered in all stages. In situ hybridization analysis revealed an embryonic limited ubiquitous pattern of OGA during egg development, while GFAT is expressed in both embryonic and extra-embryonic cells. Finally, parental knock down of OGT by RNA interference (RNAi) shows physiological impairment of oocyte maturation and a decrease in egg laying and embryonic survival, while OGA knockdown did not lead to physiologically and phenotypic significant changes. Altogehter, these results provide an important characterization of the O-GlcNAc machinery in the most diverse order of insects, and suggest a critical role of O-GlcNAcylation in a stage-specific manner during Tribolium castaneum development.