Armadillo-related proteins promote lateral root development in Arabidopsis.
Armadillo/beta-catenin and related proteins have important functions during animal and Dictyostelium development, regulating cell differentiation, proliferation, and adhesion. Armadillo-repeat-containing proteins also exist in plants, but the majority have unknown roles. The Arabidopsis genes that show greatest sequence homology to Armadillo/beta-catenin are called ARABIDILLO-1 and -2. Here, we demonstrate that ARABIDILLO-1 and -2 promote lateral root development. arabidillo-1/-2 mutants form fewer lateral roots, and ARABIDILLO-1-overexpressing lines produce more lateral roots than wild-type seedlings. ARABIDILLO-yellow fluorescent protein fusions are nuclear. ARABIDILLO proteins contain an F-box motif, and thus may target other proteins for proteasomal degradation. Overexpression of ARABIDILLO-1 protein fragments, including F-box fragments, in wild-type seedlings reduces lateral root formation to the level of the arabidillo-1/-2 mutant. We have shown that plant beta-catenin-related proteins regulate root development. We suggest that ARABIDILLO proteins may target an inhibitor of lateral root development for degradation and propose that Arabidopsis beta-catenin-related proteins define a previously uncharacterized pathway that promotes root branching.
Coates
Juliet C
JC
School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom. j.c.coates@bham.ac.uk
Laplaze
Laurent
L
Haseloff
Jim
J
D000818:Animals; D017360:Arabidopsis / Q000378:metabolism* / Q000502:physiology; D029681:Arabidopsis Proteins / Q000502:physiology; D051186:Armadillo Domain Proteins / Q000378:metabolism / Q000502:physiology*; D001426:Bacterial Proteins / Q000378:metabolism; D002448:Cell Adhesion; D002454:Cell Differentiation; D002467:Cell Nucleus / Q000378:metabolism; D003001:Cloning, Molecular; D004252:DNA Mutational Analysis; D004023:Dictyostelium / Q000378:metabolism; D008164:Luminescent Proteins / Q000378:metabolism; D008957:Models, Genetic; D009154:Mutation; D010641:Phenotype; D018521:Plant Physiological Phenomena; D010940:Plant Proteins / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D051176:beta Catenin / Q000378:metabolism / Q000502:physiology
D029681:Arabidopsis Proteins; D051186:Armadillo Domain Proteins; D001426:Bacterial Proteins; D008164:Luminescent Proteins; D010940:Plant Proteins; C508786:arabidillo-1 protein, Arabidopsis; C508787:arabidillo-2 protein, Arabidopsis; D051176:beta Catenin; C054562:yellow fluorescent protein, Bacteria