Additional transcriptional regulation of WER

Establish whether WEREWOLF (WER) transcription in the Arabidopsis root epidermis is subject to additional regulation beyond repression by the cortical positional signal.

Background

Arabidopsis root epidermal patterning is controlled by a complex regulatory network centered on the WER/MYB23–GL3/EGL3–TTG1 transcriptional complex. WER promotes GL2 transcription and atrichoblast fate, and its transcription is thought to be negatively regulated by a cortical signal. Prior modelling suggested extra regulation of WER might be required and could involve repression by CAPRICE (CPC), whereas experimental work proposed competition for GL3/EGL3 between WER and CPC could be sufficient.

In this paper, the authors integrated updated network knowledge into a mathematical model and report that successful reproduction of wild type and scm mutant patterns required adding WER repression by a factor co-localized with the CPC complex, suggesting incomplete understanding of WER transcriptional control remains. The explicit open question highlights the need to verify whether additional WER regulation exists beyond the cortical signal.