HAIRY MERISTEM with WUSCHEL confines CLAVATA3 expression to the outer apical meristem layers ($) (Science)

The interaction between transcription factors WUSCHEL (WUS) and CLAVATA3 (CLV3) controls the size of the meristem. Although WUS is known to activate CLV3 expression, their expression domains don’t fully overlap, with CLV3 being restricted to the upper part of the meristem. Previously, in the multiple ham mutant (loss of function of HAIRY MERISTEM family) CLV3 expression was observed in the lower, rib meristem. Using computational and experimental approaches, Zhou et al. showed that WUS activates CLV3 only in the absence of HAM. Their model faithfully predicts the expression domain of CLV3 in a variety of mutant backgrounds, and during de novo meristem formation in leaf axils. (Summary by Mary Williams) Science 10.1126/science.aar8638