Article
Preferential and Asymmetrical Accumulation of a Rac Small GTPase mRNA in Differentiating Xylem Cells of Zinnia elegans
Authors: Nakanomyo I.1; Kost B.2; Chua N-H.2; Fukuda H.1
Source: Plant and Cell Physiology, Volume 43, Number 12, 15 December 2002 , pp. 1484-1492(9)
Publisher: Oxford University Press
Abstract:
Rac-type small GTPases are known to function in some cellular processes in plants. To further understand the involvement of Rac type GTPases in plant development, we isolated from cultured Zinnia cells a gene (ZeRAC2) encoding a new Rac-type small GTPase. ZeRAC2 mRNA accumulates preferentially in xylogenic culture and transiently at the time when visible tracheary elements appear. Experiments with ZeRAC2 recombinant proteins demonstrated that ZeRAC2 binds to and hydrolyzes GTP. A GFPZeRAC2 fusion protein was localized to the plasma membrane. Together with the fact that ZeRAC2 possesses a putative geranylgeranylation site at the C-terminus, this suggests that ZeRAC2 acts on the plasma membrane. In situ hybridization indicated that ZeRAC2 mRNA accumulates preferentially in xylem parenchyma and tracheary element precursor cells, and surprisingly the accumulation is restricted to the site facing developing tracheary elements.
Document Type: Original article
Affiliations: 1: Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan 2: Laboratory of Plant Molecular Biology, The Rockefeller University, 1230 York Avenue, New York, NY 10021-6399, U.S.A.

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