WUSCHEL protein movement mediates stem cell homeostasis in the Arabidopsis shoot apex

Ram Kishor Yadav; Mariano Perales; Jérémy Gruel; Thomas Girke; Henrik Jönsson; G. Venugopala Reddy

doi:10.1101/gad.17258511

WUSCHEL protein movement mediates stem cell homeostasis in the Arabidopsis shoot apex

¹Department of Botany and Plant Sciences, Center for Plant Cell Biology (CEPCEB), Institute of Integrative Genome Biology (IIGB), University of California at Riverside, Riverside, California 92521, USA;
²Computational Biology and Biological Physics Group, Department of Astronomy and Theoretical Physics, Lund University, SE-223 62 Lund, Sweden

↵3 These authors contributed equally to this work.

↵4 Present address: Faculty of Life Sciences and Biotechnology, South Asian University, JNU Campus, New Delhi 110067, India.

Abstract

WUSCHEL (WUS) is a homeodomain transcription factor produced in cells of the niche/organizing center (OC) of shoot apical meristems. WUS specifies stem cell fate and also restricts its own levels by activating a negative regulator, CLAVATA3 (CLV3), in adjacent cells of the central zone (CZ). Here we show that the WUS protein, after being synthesized in cells of the OC, migrates into the CZ, where it activates CLV3 transcription by binding to its promoter elements. Using a computational model, we show that maintenance of the WUS gradient is essential to regulate stem cell number. Migration of a stem cell-inducing transcription factor into adjacent cells to activate a negative regulator, thereby restricting its own accumulation, is a theme that is unique to plant stem cell niches.