MAP20, a Microtubule-Associated Protein in the Secondary Cell Walls of Hybrid Aspen, Is a Target of the Cellulose Synthesis Inhibitor 2,6-Dichlorobenzonitrile
2008 (English)In: Plant Physiology, ISSN 0032-0889, E-ISSN 1532-2548, Vol. 148, no 3, 1283-1294 p.Article in journal (Refereed) Published
We have identified a gene, denoted PttMAP20, which is strongly up-regulated during secondary cell wall synthesis and tightly coregulated with the secondary wall-associated CESA genes in hybrid aspen (Populus tremula x tremuloides). Immunolocalization studies with affinity-purified antibodies specific for PttMAP20 revealed that the protein is found in all cell types in developing xylem and that it is most abundant in cells forming secondary cell walls. This PttMAP20 protein sequence contains a highly conserved TPX2 domain first identified in a microtubule-associated protein (MAP) in Xenopus laevis. Overexpression of PttMAP20 in Arabidopsis (Arabidopsis thaliana) leads to helical twisting of epidermal cells, frequently associated with MAPs. In addition, a PttMAP20-yellow fluorescent protein fusion protein expressed in tobacco (Nicotiana tabacum) leaves localizes to microtubules in leaf epidermal pavement cells. Recombinant PttMAP20 expressed in Escherichia coli also binds specifically to in vitro-assembled, taxol-stabilized bovine microtubules. Finally, the herbicide 2,6-dichlorobenzonitrile, which inhibits cellulose synthesis in plants, was found to bind specifically to PttMAP20. Together with the known function of cortical microtubules in orienting cellulose microfibrils, these observations suggest that PttMAP20 has a role in cellulose biosynthesis.
Place, publisher, year, edition, pages
2008. Vol. 148, no 3, 1283-1294 p.
carbohydrate-active enzymes, plant functional genomics, kinesin-like, protein, cortical microtubules, plasma-membrane, wood formation, arabidopsis-thaliana, conifer tracheids, angiosperm trees, urea solution
IdentifiersURN: urn:nbn:se:kth:diva-17951DOI: 10.1104/pp.108.121913ISI: 000260719500010ScopusID: 2-s2.0-57749101097OAI: oai:DiVA.org:kth-17951DiVA: diva2:335996
QC 201005252010-08-052010-08-052016-09-05Bibliographically approved