Drosophila Oga deletion perturbs O-GlcNAcylation of chromatin factors. Drosophila melanogaster

Drosophila development is a complex and dynamic process regulated, in part, by members of the Polycomb (Pc), Trithorax (Trx) and Compass chromatin modifier complexes. O-GlcNAc Transferase (OGT/SXC) is essential for Pc repression suggesting that the O-GlcNAcylation of proteins plays a key role in regulating development. OGT transfers N-acetyl-D-glucosamine (GlcNAc) onto hydroxyl groups of serine or threonine residues of key transcriptional regulators using the nutrient-derived UDP-GlcNAc as a substrate, which is dynamically removed by O-GlcNAcase (OGA). We performed ChIP-chip and microarray analysis after OGT or OGA RNAi knockdown in Drosophila S2 cells and found that O-GlcNAc was elevated genome wide particularly at genes related to mitosis and cell cycle in OGA RNAi cells, but not at sites co-occupied by Pc member Pleiohomeotic (Pho), such as the Hox and NK homeobox gene clusters. Microarray analysis suggested that altered O-GlcNAc cycling perturbed the expression of genes associated with morphogenesis and cell cycle regulation. To examine the in vivo consequences of disturbed O-GlcNAc cycling in the whole animal, we produced a null allele of oga (ogadel.1) in Drosophila. Epigenetic activators including Trx group members Trithorax (Trx), Absent small or homeotic discs 1 (Ash1) and Compass member Set1 histone methyltransferases are O-GlcNAc modified in ogadel.1 mutants. ogadel.1 mutants displayed altered expression of a distinct set of cell cycle related genes in ovaries. Our results suggest that the loss of OGA could affect epigenetic machinery by accumulating O-GlcNAc on numerous chromatin factors including Trx, Ash1 and Set1 in Drosophila. Overall design: We performed affymetrix tilingarray analysis after OGT or OGA RNAi knockdown in Drosophila S2 cells to find if that O-GlcNAc was elevated genome wide particularly at genes related to mitosis and cell cycle in OGA RNAi cells, but not at sites co-occupied by Pc member Pleiohomeotic (Pho), ------------------------------- This represents the gene expression component only