Horizon 1 1 17 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES Proceedings of the National Academy of Sciences of the United States of America 1621-1626 plant beta catenin arabidillo 2006 fdi:010052290 ENG Proceedings of the National Academy of Sciences of the United States of America CC:0002350943-0083 5 10.1073/pnas.0507575103 https://www.documentation.ird.fr/hor/fdi:010052290 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/2025-01/010052290.pdf 103 Horizon (IRD) lArmadillo/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 13-catenin-related proteins define a previously uncharacterized pathway that promotes root branching.