Purification And Characterization Of G Protein From Arabidopsis Thaliana And Effects Of Different Treatment On Gα Protein Expression

G protein coupled signaling is an important signal pathway, and is involved in regulating many activities in plant cells. G protein was first discovered in animals in the 1980s, and the mechanism of G protein coupled signaling has been widely studied. Research in plants started in later 1980s. Arabidopsis is a model plant, the analysis of its genome sequence indicate that: there is only one gene encodeαsubunit(GPA1); one gene encodingβsubunit(AGB1); and two genes encodingγsubunit(AGG1, AGG2). Results from recent studies on G protein coupled signaling show that: the analysis of interaction between Gα,Gβand Gγis very important for us to elucidate the mechanisms and functions of G protein in higher plants.To achieve this, G protein should be purified.In this research, the suspend-cultured wide-type cells of Arabidopsis Thaliana (Col) were used as the experimental material. The G protein was purified from the cell by ultrasonic fragmentation,deposited by ammonium sulphate,gel filtration, ion exchange, SDS-PAGE, Native-PAGE, Western blotting etc. We optimized the method of purification, and provided some theoretical foundations for further investigation. At the same time, seedlings and cells were treated with a series of treatments such as soil drying,PEG-8000, NaCl, hormone, CTX, H2O2, different temperature, etc. All these treatments caused different effects on Gαexpression, which proved that Gαwas involved in many signal pathways. The major results were showed as follows:1. Optimized the method of G protein purification: cell fragmented by ultrasonic; then grounded and centrifuged; deposited by ammonium sulfate with 40-60% saturation; filtered through Sephadex G-25 gel; DEAE-Sepharose Fast Flow ion exchange, and...