Developmental regulation and significance of KNOX protein trafficking in Arabidopsis

Kim, J. Y., Yuan, Z., Jackson, D. P. (September 2003) Developmental regulation and significance of KNOX protein trafficking in Arabidopsis. Development, 130 (18). pp. 4351-4362. ISSN 0950-1991

DOI: 10.1242/dev.00618


Intercellular communication delivers critical information for position-dependent specification of cell fate. In plants, a novel mechanism for cell-to-cell communication involves the intercellular trafficking of regulatory proteins and mRNAs. The maize KNOTTED1 (KN1) gene acts non cell-autonomously in the maize leaf, and KN1 was the first plant protein shown to traffic cell-to-cell, presumably through plasmodesmata. We have compared the intercellular trafficking of green fluorescent protein (GFP) fusions of KN1 and Arabidopsis KN1-related homeobox proteins to that of the viral movement protein from turnip vein clearing tobamovirus. We show that there is specific developmental regulation of GFPsimilar toKN1 trafficking. GFPsimilar toKN1 was able to traffic from the inner layers of the leaf to the epidermis, but not in the opposite direction, from epidermis to mesophyll. However, GFP or the GFPsimilar tomovement protein fusion moved readily out of the epidermis. GFPsimilar toKN1 was however able to traffic out of the epidermal (L1) layer in the shoot apical meristem, indicating that KN1 movement out of the L1 was developmentally regulated. GFPsimilar toKNAT1/BREVIPEDICELLUS and GFPsimilar toSHOOTMERISTEMLESS fusions could also traffic from the L1 to the L2/L3 layers of the meristem. In a test for the functional significance of trafficking, we showed that L1-specific expression of KN1 or of KNAT1 was able to partially complement the strong shootmetistemless-11 (stm-11) mutant. However, a cell-autonomous GUS fusion to KN1 showed neither trafficking ability nor complementation of stm-11 when expressed in the L1. These results suggest that the activity of KN1 and related homeobox proteins is maintained following intercellular trafficking, and that trafficking may be required for their normal developmental function.

Item Type: Paper
Uncontrolled Keywords: homeodomain KNOX shoot meristem knotted1 GFP plasmodesmata protein trafficking Arabidopsis thaliana CELL-TO-CELL cell to cell TOBACCO-MOSAIC-VIRUS Tobacco Mosaic virus GREEN-FLUORESCENT PROTEIN Green Flourescent Protein VIRAL MOVEMENT PROTEIN movement protein PLANT HOMEODOMAIN PROTEINS plant homeodomain proteins LONG-DISTANCE MOVEMENT long distance movement MAIZE HOMEOBOX GENE maize homeobox gene SUBCELLULAR-LOCALIZATION subcellular localization SHOOT MERISTEMLESS shoot meristemless MESSENGER-RNA messenger RNA
Subjects: organism description > plant > Arabidopsis
organism description > plant > maize
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > knotted1
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > genes, structure and function > genes: types > knotted1
CSHL Authors:
Communities: CSHL labs > Jackson lab
Depositing User: CSHL Librarian
Date: September 2003
Date Deposited: 03 Apr 2012 17:57
Last Modified: 11 Jan 2017 21:36
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