萬年松和阿拉伯芥WD repeat基因功能上分析及研究

Selaginella tamariscina, a resurrection fern-allied plant, can survive from desiccation. In our study, differential display was the strategy employed to screen the dehydration activated gene bands that may be involved in mechanisms of desiccation tolerance in S. tamariscina. The full length of cDNA was obtained using RACE（Rapid Amplification of cDNA Ends）technique and then blast on NCBI website to get possible orthologs. We report a study on StWDR, one of the dehydration inducible genes, in Selaginella. The expression of StWDR was induced by dehydration, abscisic acid, salt, cold, heat shock and osmotic stress. Searching for the homolog in Arabidopsis, we found MSI2（multicopy suppressor of IRA 2）shows the higher homology with StWDR. The similarity of protein sequence between StWDR and MSI2 is 68％. StWDR and MSI2 are both WDR proteins. The msi2 T-DNA mutants and MSI2-overexpressing transgenic plants exhibited the same phenotype as wild-type. The expression of MSI2 gene in 2-week-old wild-type Arabidopsis did not respond to drought, salt, high temperature, low temperature, mannitol, abscisic acid, gibberellic acid, salicylic acid and jasmonic acid. Localization study using a fusion protein consisting of the full length of MSI2 coding sequence and GFP under the control of 35S promoter revealed that fluorescence was detected in both the cytosol and the nucleus but not in the chloroplasts. MSI2 pro-GUS transgenic plants revealed that strong GUS activities were found in stem apical meristem, hypocotyls, roots and floral buds but weak GUS activities in cotyledons and trichomes. To investigate the biological function of MSI2, we performed a screen for MSI2-interacting proteins using the yeast two-hybrid system. We have identified 42 proteins that can be grouped into three categories: ribosomal proteins involved in protein synthesis, two-component signal transduction proteins, and organelle proteins. In the third group, many proteins like electron transporters, photosystem reaction center proteins, cyclophilins and proteins involved in vesicle-mediated formation of thylakoid membranes were found, indicating a major function of MSI2 may be related to the intracellular protein trafficking in Arabidopsis thaliana.

並列關鍵字

Arabidopsis thaliana

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萬年松和阿拉伯芥WD repeat基因功能上分析及研究

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