Abstract
In this issue of Genes & Development, Kim and colleagues (pp. 490-502) report that the Drosophila circadian repressor dPER undergoes O-linked GlcNAcylation (O-GlcNAc). Their data show that manipulation of the relevant O-GlcNAc transferase (OGT) regulates behavioral rhythmicity by affecting the stability and nuclear translocation of dPER.