Transcription factor binding at Ig enhancers is linked to somatic hypermutation targeting.

Secondary diversification of the Ig repertoire occurs through somatic hypermutation (SHM), gene conversion (GCV), and class switch recombination (CSR)-three processes that are initiated by activation-induced cytidine deaminase (AID). AID targets Ig genes at orders of magnitude higher than the rest of the genome, but the basis for this specificity is poorly understood. We have previously demonstrated that enhancers and enhancer-like sequences from Ig genes are capable of stimulating SHM of neighboring genes in a capacity distinct from their roles in increasing transcription.

The Arabidopsis O-fucosyltransferase SPINDLY activates nuclear growth repressor DELLA.

Plant development requires coordination among complex signaling networks to enhance the plant's adaptation to changing environments. DELLAs, transcription regulators originally identified as repressors of phytohormone gibberellin signaling, play a central role in integrating multiple signaling activities via direct protein interactions with key transcription factors. Here, we found that DELLA is mono-O-fucosylated by the novel O-fucosyltransferase SPINDLY (SPY) in Arabidopsis thaliana.

O-GlcNAcylation of master growth repressor DELLA by SECRET AGENT modulates multiple signaling pathways in Arabidopsis.

The DELLA family of transcription regulators functions as master growth repressors in plants by inhibiting phytohormone gibberellin (GA) signaling in response to developmental and environmental cues. DELLAs also play a central role in mediating cross-talk between GA and other signaling pathways via antagonistic direct interactions with key transcription factors. However, how these crucial protein-protein interactions can be dynamically regulated during plant development remains unclear.