This Article Full Text Full Text (PDF) All Versions of this Article: 139/2/734    most recent pp.105.066639v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via ISI Web of Science (6) Citing Articles via Google Scholar Google Scholar Articles by O'Brien, M. Articles by Matton, D. P. Search for Related Content PubMed PubMed Citation Articles by O'Brien, M. Articles by Matton, D. P. Agricola Articles by O'Brien, M. Articles by Matton, D. P.

DEVELOPMENT AND HORMONE ACTION

Lipid Signaling in Plants. Cloning and Expression Analysis of the Obtusifoliol 14-Demethylase from Solanum chacoense Bitt., a Pollination- and Fertilization-Induced Gene with Both Obtusifoliol and Lanosterol Demethylase Activity¹

Institut de Recherche en Biologie Végétale, Département de Sciences Biologiques, Université de Montréal, Montreal, Quebec, Canada, H1X 2B2 (M.O., S.-C.C., D.P.M.); and Département Isoprénoïdes, Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique, Unité Propre de Recherche 2357, 67083 Strasbourg cedex, France (A.R.)

The sterol 14-demethylase (CYP51) is the most widely distributed cytochrome P450 gene family being found in all biological kingdoms. It catalyzes the first step following cyclization in sterol biosynthesis, leading to the formation of precursors of steroid hormones, including brassinosteroids, in plants. Most enzymes involved in the plant sterol biosynthesis pathway have been characterized biochemically and the corresponding genes cloned. Genes coding for enzymes promoting substrate modifications before 24-methylenelophenol lead to embryonic and seed defects when mutated, while mutants downstream the 24-methylenelophenol intermediate show phenotypes characteristic of brassinosteroid mutants. By a differential display approach, we have isolated a fertilization-induced gene, encoding a sterol 14-demethylase enzyme, named CYP51G1-Sc. Functional characterization of CYP51G1-Sc expressed in yeast (Saccharomyces cerevisiae) showed that it could demethylate obtusifoliol, as well as nontypical plant sterol biosynthetic intermediates (lanosterol), in contrast with the strong substrate specificity of the previously characterized obtusifoliol 14-demethylases found in other plant species. CYP51G1-Sc transcripts are mostly expressed in meristems and in female reproductive tissues, where they are induced following pollination. Treatment of the plant itself with obtusifoliol induced the expression of the CYP51G1-Sc mRNA, suggesting a possible role of this transient biosynthetic intermediate as a bioactive signaling lipid molecule. Furthermore, treatments of leaves with ¹⁴C-labeled obtusifoliol demonstrated that this sterol could be transported in distal parts of the plant away from the sprayed leaves. Arabidopsis (Arabidopsis thaliana) CYP51 homozygous knockout mutants were also lethal, suggesting important roles for this enzymatic step and its substrate in plant development.

Article, publication date, and citation information can be found at www.plantphysiol.org/cgi/doi/10.1104/pp.105.066639.

^* Corresponding author; e-mail dp.matton{at}umontreal.ca; fax 514–872–9406.

Received June 6, 2005; returned for revision July 20, 2005; accepted July 22, 2005.

This article has been cited by other articles:

				M. Gray-Mitsumune, M. O'Brien, C. Bertrand, F. Tebbji, A. Nantel, and D. P. Matton Loss of ovule identity induced by overexpression of the fertilization-related kinase 2 (ScFRK2), a MAPKKK from Solanum chacoense J. Exp. Bot., December 1, 2006; 57(15): 4171 - 4187. [Abstract] [Full Text] [PDF]

				G. I. Lepesheva, N. G. Zaitseva, W. D. Nes, W. Zhou, M. Arase, J. Liu, G. C. Hill, and M. R. Waterman CYP51 from Trypanosoma cruzi: A PHYLA-SPECIFIC RESIDUE IN THE B' HELIX DEFINES SUBSTRATE PREFERENCES OF STEROL 14{alpha}-DEMETHYLASE J. Biol. Chem., February 10, 2006; 281(6): 3577 - 3585. [Abstract] [Full Text] [PDF]