Analyses On AtRGS1 Protein Localization And Function In Arabidopsis Seed Germination And Early Seedling Development

Many extracellus stimuli rely on heterotrimeric GTP binding proteins (G proteins). Regulator of G-protein signaling (RGS) proteins accelerate the deactivation of Gαsubunits to terminate G protein signaling. A novel RGS protein (AtRGS1) has been recognized in Arabidopsis thaliana which has a predicted seven-transmembrane (7TM) structure as well as an RGS box with GTPase accelerating activity, and desensitizes the G-protein-mediated signaling.A number of largely pharmacological and molecular genetics studies suggested that plant G proteins involvement in a variety of processes including light-mediated responses, ABA and GA signaling, regulation of ion channels and pathogen resistance. But little is known about the function of AtRGS1 protein since the first identified by Chen et al. (2003). Therefore, study the role of AtRGS1 protein in plant growth and development is extreme importance. The roles of AtRGS1 protein in Arabidopsis were investigated in the present study, using seeds that carry a null mutation in the genes encoding RGS protein (AtRGS1) and the alpha subunit (AtGPA1) of the G protein in Arabidopsis, named rgs1-2 and gpa1-3 respectively as well as the wild type Col, with different approaches such as molecular biology, genetics and biochemistry. The main results were as follows:The 35S-AtRGS1 overexpression system was constructed by TOPO cloning, and the transgenic cell suspension of Col was constructed. Protein localization analysis using AtRGS1-GFP fusion protein technique showed that, the AtRGS1 protein was localized in plasma membrane and the subcellular localization of AtRGS1 protein was affected by ABA treatment both in protoplasts and cells. The expression of AtRGS1...