Poster: Vegetative development

Abs # 329: Functional Analysis of Extra-Large G-Proteins in Arabidopsis

Presenter:	Ding, Lei , LXD187@psu.edu
Authors	Ding, Lei  (A)   Gibson, Caroline A (A)   Assmann, Sarah M (A)
Affiliations:	(A): Pennsylvania State University

Heterotrimetric GTP-binding proteins, composed of α, β, and γ subunits, play important roles in signal transduction in plant cells, including roles in the regulation of stomatal apertures and cell division processes (Assmann, 2002). Besides the sole canonical G protein α subunit gene (GPA1), a gene encoding a special GTP-binding protein, "extra-large GTP-binding protein" (AtXLG1), was isolated from Arabidopsis thaliana in our laboratory (Lee and Assmann, 1999). The Arabidopsis genome contains three genes (AtXLGs) encoding extra-large GTP-binding proteins of this type. The carboxy-terminal region of each conceptually translated AtXLG is homologous to GPA1, while the amino-terminal region contains a putative nuclear localization signal and a cysteine-rich region. We are employing reverse genetic strategies to study the functions of the AtXLGs. We have acquired T-DNA insertional mutants of each AtXLG. To identify phenotypes, single, double, and triple atxlg mutants are being tested in soil and on agar plates under a variety of conditions. Gene expression patterns are being studied by GUS staining of AtXLG-promoter::GUS lines. The subcellular localization of these proteins is also being studied by transient expression of AtXLG:GFP fusion proteins via particle bombardment. Characterization of the AtXLGs with regard to these aspects will be reported at the meeting. Supported by USDA grants 2001-35304-09916 and 2003-35304-13924 to SMA. Assmann, S.M. (2002), Plant Cell, Supplement, S355-S373. Lee Y.-R. J. and S.M. Assmann (1999), Plant Mol. Biol., 40:55-64