title: Microtubule basis for left-handed helical growth in Arabidopsis.
abstract: Left-right asymmetry in plants can be found in helices of stalks, stems and tendrils, and in fan-like petal arrangements. The handedness in these asymmetric structures is often fixed in given species, indicating that genetic factors control asymmetric development. Here we show that dominant negative mutations at the tubulin intradimer interface of alpha-tubulins 4 and 6 cause left-handed helical growth and clockwise twisting in elongating organs of Arabidopsis thaliana. We demonstrate that the mutant tubulins incorporate into microtubule polymers, producing right-handed obliquely oriented cortical arrays, in the root epidermal cells. The cortical microtubules in the mutants had increased sensitivity to microtubule-specific drugs. These results suggest that reduced microtubule stability can produce left-handed helical growth in plants.
authors: Graduate School of Biological Sciences, Nara Institute of Science and Technology, Takayama 8916-5, Ikoma 630-0101, Japan.
authors: Siripong
authors: S
authors: Thitamadee
authors: Kazuko
authors: K
authors: Tuchihara
authors: Takashi
authors: T
authors: Hashimoto
mesh_terms: D017360:Arabidopsis / Q000166:cytology* / Q000235:genetics / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D019281:Dimerization; D017343:Genes, Plant / Q000235:genetics; D008870:Microtubules / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype; D059828:Plant Cells; D063245:Plant Development; D010944:Plants / Q000235:genetics; D030821:Plants, Genetically Modified; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D008941:Spindle Apparatus / Q000378:metabolism; D013489:Suppression, Genetic / Q000235:genetics; D014404:Tubulin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D014404:Tubulin