Regulation of intercellular target of monopteros 7 protein transport in the arabidopsis root
Lu, Kuan Ju ; Rybel, Bert De; Mourik, Hilda Van; Weijers, Dolf - \ 2018
Development 145 (2018)2. - ISSN 0950-1991
Cell-cell communication - Embryogenesis - Plasmodesmata - Protein transport - RAM - TMO7
Intercellular communication coordinates hypophysis establishment in the Arabidopsis embryo. Previously, TARGET OF MONOPTEROS 7 (TMO7) was reported to be transported to the hypophysis, the founder cell of the root cap, and RNA suppression experiments implicated its function in embryonic root development. However, the protein properties and mechanisms mediating TMO7 protein transport, and the role the movement plays in development remained unclear. Here, we report that in the post-embryonic root, TMO7 and its close relatives are transported into the root cap through plasmodesmata in a sequence-dependent manner. We also show that nuclear residence is crucial for TMO7 transport, and postulate that modification, potentially phosphorylation, labels TMO7 for transport. Additionally, three novel CRISPR/Cas9-induced tmo7 alleles confirmed a role in hypophysis division, but suggest complex redundancies with close relatives in root formation. Finally, we demonstrate that TMO7 transport is biologically meaningful, as local expression partially restores hypophysis division in a plasmodesmal protein transport mutant. Our study identifies motifs and amino acids that are pivotal for TMO7 protein transport, and establishes the importance of TMO7 in hypophysis and root development.
The logic of communication : Roles for mobile transcription factors in plants
Long, Yuchen ; Scheres, Ben ; Blilou, Ikram - \ 2015
Journal of Experimental Botany 66 (2015)4. - ISSN 0022-0957 - p. 1133 - 1144.
Asymmetric cell division - Cell-cell communication - Intercellular signalling - Mobile transcritption factors - Protein movement - Regulatory networks
Mobile transcription factors play many roles in plant development. Here, we compare the use of mobile transcription factors as signals with some canonical signal transduction processes in prokaryotes and eukaryotes. After an initial survey, we focus on the SHORT-ROOT pathway in Arabidopsis roots to show that, despite the simplicity of the concept of mobile transcription factor signalling, many lines of evidence reveal a surprising complexity in control mechanisms linked to this process. We argue that these controls bestow precision, robustness, and versatility on mobile transcription factor signalling.