Cre/loxP,a site-specific recombination system,has been widely used for various purposes,including chromosomal translocations,generation of marker-free transgenic plants,tissue-specific activation of a reporter gene an...Cre/loxP,a site-specific recombination system,has been widely used for various purposes,including chromosomal translocations,generation of marker-free transgenic plants,tissue-specific activation of a reporter gene and efficient heterologous gene expression in plants.However,stable or transient expression of Cre recombinase in plants can cause chlorosis or necrosis.Here,we describe a modified Cre/loxP recombination system using a DNA fragment flanked with loxP sites in the same orientation in which necrosis induced by Cre recombinase in Nicotiana benthamiana leaves was alleviated.The modified system was successfully used to create functional GFP-tagged pepper mild mottle virus(PMMoV)and a chimeric virus with coat protein(CP)substitution assembled from separate pro-vector modules.Our results provide a new strategy and flexible technique to construct chimeric virus and infectious clones for plant viruses with large genomes.展开更多
Phospholipid hydroperoxide glutathione peroxidase is an antioxidant enzyme that has the highest capability of reducing membrane-bound hydroperoxy lipids as compared to free organic and inorganic hydroperoxides amongst...Phospholipid hydroperoxide glutathione peroxidase is an antioxidant enzyme that has the highest capability of reducing membrane-bound hydroperoxy lipids as compared to free organic and inorganic hydroperoxides amongst the glutathione peroxidases.In this study,urea-induced effects on the inactivation and unfolding of a recombinant phospholipid hydroperoxide glutathione peroxidase（PHGPx）from Oryza sativa were investigated by means of circular dichroism and fluorescence spectroscopy.With the increase of urea concentration,the residual activity of OsPHGPx decreases correspondingly.When the urea concentration is above 5.0 mol/L,there was no residual activity.In addition,the observed changes in intrinsic tryptophan fluorescence,the binding of the hydrophobic fluorescence probe ANS,and the far UV CD describe a common dependence on the concentration of urea suggesting that the conformational features of the native OsPHGPx are lost in a highly cooperative single transition.The unfolding process comprises of three zones：the native base-line zone between 0 and 2.5 mol/L urea,the transition zone between 2.5 and 5.5 mol/L urea,and the denatured base-line zone above 5.5 mol/L urea.The transition zone has a midpoint at about 4.0 mol/L urea.展开更多
基金supported by the National Key R&D Program of China(2019YFD1001800)the China Agriculture Research System of MOF and MARA(CARS24-C-04)+1 种基金supported by the Science&Technology Public Welfare Project of Ningbo City,China(202002N3005)K.C.Wong Education Foundation,China。
文摘Cre/loxP,a site-specific recombination system,has been widely used for various purposes,including chromosomal translocations,generation of marker-free transgenic plants,tissue-specific activation of a reporter gene and efficient heterologous gene expression in plants.However,stable or transient expression of Cre recombinase in plants can cause chlorosis or necrosis.Here,we describe a modified Cre/loxP recombination system using a DNA fragment flanked with loxP sites in the same orientation in which necrosis induced by Cre recombinase in Nicotiana benthamiana leaves was alleviated.The modified system was successfully used to create functional GFP-tagged pepper mild mottle virus(PMMoV)and a chimeric virus with coat protein(CP)substitution assembled from separate pro-vector modules.Our results provide a new strategy and flexible technique to construct chimeric virus and infectious clones for plant viruses with large genomes.
基金Supported by the National Basic Research Program of China(No.2006CB101706)the Hi-tech Research and DevelopmentProgram of China(No.2007AA100604)the National Natural Science Foundation of China(Nos.30170080and39770078).
文摘Phospholipid hydroperoxide glutathione peroxidase is an antioxidant enzyme that has the highest capability of reducing membrane-bound hydroperoxy lipids as compared to free organic and inorganic hydroperoxides amongst the glutathione peroxidases.In this study,urea-induced effects on the inactivation and unfolding of a recombinant phospholipid hydroperoxide glutathione peroxidase（PHGPx）from Oryza sativa were investigated by means of circular dichroism and fluorescence spectroscopy.With the increase of urea concentration,the residual activity of OsPHGPx decreases correspondingly.When the urea concentration is above 5.0 mol/L,there was no residual activity.In addition,the observed changes in intrinsic tryptophan fluorescence,the binding of the hydrophobic fluorescence probe ANS,and the far UV CD describe a common dependence on the concentration of urea suggesting that the conformational features of the native OsPHGPx are lost in a highly cooperative single transition.The unfolding process comprises of three zones：the native base-line zone between 0 and 2.5 mol/L urea,the transition zone between 2.5 and 5.5 mol/L urea,and the denatured base-line zone above 5.5 mol/L urea.The transition zone has a midpoint at about 4.0 mol/L urea.
