Poster: Cytoskeleton: Structure & Function

Abs # 1117: WVD2 is a novel plant protein that affects anisotropic cell expansion and helical growth

Presenter:	Perrin, Robyn M, rmperrin@wisc.edu
Authors	Perrin, Robyn M (A)   Yuen, Christen YL (A)   Will, Jessica  (A)   Baskin, Tobias I (B)   Masson, Patrick H (A)
Affiliations:	(A): University of Wisconsin (B): University of Missouri, Columbia

Arabidopsis roots exhibit characteristic growth patterns in response to gravity and asymmetric mechanical stimuli; for example, roots of most ecotypes skew to the right and form sinusoidal waves on tilted agar surfaces. We have identified the gain-of-function mutant wave-dampened 2-1 (wvd2-1), which shows root wave dampening and leftward skewing (Yuen et al., Plant Physiol 2003 131:493). wvd2-1 has impaired anisotropic cell expansion in multiple organs. Cortical microtubules are oriented aberrantly in regions of wvd2-1 roots. WVD2 is a small, highly charged novel protein containing a conserved region predicted to form a coiled-coil structure. It is a member of a small family of predicted proteins in Arabidopsis and a larger family in dicots, monocots, and lower nonvascular plants. The PROPSEARCH algorithm, which detects remote homologs using protein compositional features, indicates compositional similarity between WVD2 and SCG10-like proteins, which in animals affect neuronal elongation by influencing microtubule stability. Biochemical studies indicate that purified epitope-tagged WVD2 protein co-sediments with microtubules during in vitro binding assays, and data will be presented on the affect of WVD2 on microtubule stability. Additionally, we are assessing the causes of altered root growth in wvd2-1 by quantifying the spatial distribution of elongation and rotation and the orientation of cellulose microfibrils. Finally, we will discuss results of biochemical, genetic, and yeast two-hybrid approaches aimed at identification of proteins that interact with WVD2. We will discuss the role of WVD2 and cortical microtubules in the regulation of anisotropic cell expansion and spiral root growth in Arabidopsis.