Cloning And Functional Analysis Of Glycogen Synthase Kinase Gene (OsGSK1) In Rice

Animal glycogen synthase kinase 3 (GSK-3)/SHAGGY kinases have been studied for more than 20 years, whereas plant glycogen synthase kinase 3/ SHAGGY-like kinases (GSKs) have only recently entered the scene. Present evidence indicates that plant GSKs are involved in different processes, such as flower development, brassinosteroid signaling, NaCl stress and wound responses. In contrast to mammals, which contain two genes, plants have a multigene family of GSKs. Analysis of the Arabidopsisgenome revealed the existence of ten GSK genes that fall into four distinct subfamilies. We discuss the functions and mechanisms of GSK action in rice(Oraza stiva).Full length cDNA of OsGSKl, which was a member of Rice glycogen synthase kinase 3 family, was obtained using RT-PCR technique. Searching the homologue sequences in Genebank using Blast method, we found that there are several GSK-3 homologs in other plants, such as Triticum aestivum, Zea mays, Nicotiana tabacum, Medicago sativa, Trifolium repens (white clover), Arabidopsis thaliana, etc. and there is little difference between OsGSKl and its homologs. In order to know the physical map of OsGSKl and its copy number in the rice genome DNA, southern hybridization was done using OsGSKl cDNA as the probe, and genome DNA were digested by EcoR I, Hind III restriction enzyme . Results illustrated that there was only one copy of OsGSKl in the rice genome.In order to identify the function and mechanism of OsGSKl,we did the Northern hybridization to detect its expression under abiotic stress , such as salt stress(1%), mechanical injury, ABA hormone, Cold(4°C) and Drought. Its expression level compared to the control (constitutively expressed EF~1 a gene). Results illustrated that mRNA expression increased step by step under salt stress (1% NaCl treatment 1hr, 3hr, 6hr, 12hr) .its expression was up to...