AIIopolyploidy has played an important role in plant evolution and heterosis. Recent studies indicate that the process of wide hybridization and （or） polyploidization may induce rapid and extensive genetic and epige...AIIopolyploidy has played an important role in plant evolution and heterosis. Recent studies indicate that the process of wide hybridization and （or） polyploidization may induce rapid and extensive genetic and epigenetic changes in some plant species. To better understand the allopolyploidy evolutionism and the genetic mechanism of Arachis interspecific hybridization, this study was conducted to monitor the gene expression variation by cDNA start codon targeted polymorphism （cDNA-SCoT） and cDNA high-frequency oligonucleotide-targeting active gene （cDNA-HFO-TAG） techniques, from the hybrids （F1） and newly synthesized allopolyploid generations （S0-$3） between tetraploid cultivated peanut Zhongkaihua 4 with diploid wild one Arachis doigoi. Rapid and considerable gene expression variations began as early as in the FI hybrid or immediately after chromosome doubling. Three types of gene expression changes were observed, including complete silence （gene from progenitors was not expressed in all progenies）, incomplete silence （gene expressed only in some progenies） and new genes activation. Those silent genes mainly involved in RNA transcription, metabolism, disease resistance, signal transduction and unknown functions. The activated genes with known function were almost retroelements by cDNA-SCoT technique and all metabolisms by cDNA-HFO-TAG. These findings indicated that interspecific hybridization and ploidy change affected gene expression via genetic and epigenetic alterations immediately upon allopolyploid formation, and some obtained transcripts derived fragments （TDFs） probably could be used in the research of molecular mechanism of Arachis allopolyploidization which contribute to thwe genetic diploidization of newly formed allopolyploids. Our research is valuable for understanding of peanut evolution and improving the utilization of putative and beneficial genes from the wild peanut.展开更多
Vascular endothelial growth factor （VEGF） is an angiogenic regulator that stimulates endothelial cell migration, proliferation, and angiogenesis. VEGF gene therapy is a new promising approach to induce therapeutic a...Vascular endothelial growth factor （VEGF） is an angiogenic regulator that stimulates endothelial cell migration, proliferation, and angiogenesis. VEGF gene therapy is a new promising approach to induce therapeutic angiogenesis for the treatment of ischemic myocardial and limb diseases. Recently, clinical studies have demonstrated successful outcomes using plasmids, retroviruses and adenoviruses.l-3 But the safety of those vectors is poor, which has become a serious concern. Besides immunogenicity caused by viral vectors, a further problem is that viral vectors show a preference to integrate into the transcription or control region of active genes, which may induce tumors and other disorders.展开更多
The rapid development of crops with multiple transgenic traits arouses the need for an efficient system for creating stacked cultivars. Most major crops rely on classical breeding to introgress the transgene from a la...The rapid development of crops with multiple transgenic traits arouses the need for an efficient system for creating stacked cultivars. Most major crops rely on classical breeding to introgress the transgene from a laboratory variety to the numerous cultivars adapted to different growing regions. Even with vegetative propagated crops, genetic crosses are conducted during varietal improvement prior to vegetative cloning. The probability to assort the ＇x＇ number of transgenic loci into a single genome may seem trivial, （~）x for a diploid species, but given the ＇y＇ number of other nontransgenic traits that breeders also need to assemble into the same genome, the （~）~＊y probability for a ＇breeding stack＇ could quickly make the line conversion process unmanageable. Adding new transgenes onto existing transgenic varieties without creating a new segregating locus would require site-specific integration of new DNA at the existing transgenic locus. Here, we tested a recombinase-mediated gene-stacking scheme in tobacco. Sequential site-specific inte- gration was mediated by the mycobacteriophage Bxbl integrase-catalyzed recombination between attP and attB sites. Transgenic DNA no longer needed after integration was excised by Cre recombinase-mediated recombination of Iox sites. Site-specific integration occurred in -10% of the integration events, with half of those events usable as substrates for a next round of gene stacking. Among the site-specific integrants, however, a third experienced gene silencing. Overall, precise structure and reproducible expression of the sequentially added triple traits were obtained at an overall rate of -3% of the transformed clones--a workable frequency for the development of commercial cultivars. Moreover, since nei- ther the Bxbl-att nor the Cre-lox system is under patent, there is freedom to operate,展开更多
目的观察伯氏疟原虫静息巯基氧化酶(PbQSOX)的表达阶段及表达特点。方法分别采用SignalP-5.0 Server与TMHMM Server 2.0在线软件对PbQSOX蛋白的信号肽与跨膜区进行预测分析。利用同源重组技术,将PbQSOX-HA标签型打靶质粒经限制性内切酶...目的观察伯氏疟原虫静息巯基氧化酶(PbQSOX)的表达阶段及表达特点。方法分别采用SignalP-5.0 Server与TMHMM Server 2.0在线软件对PbQSOX蛋白的信号肽与跨膜区进行预测分析。利用同源重组技术,将PbQSOX-HA标签型打靶质粒经限制性内切酶NotⅠ酶切使其线性化,将线性化的质粒电转染至伯氏疟原虫株内并感染小鼠。经乙胺嘧啶筛选耐药型疟原虫血症小鼠,取小鼠外周血进行PCR鉴定,获取PbQSOX-HA标签型疟原虫。培养纯化裂殖体、配子体与动合子阶段的PbQSOX-HA标签型疟原虫,采用蛋白质印迹法与间接免疫荧光实验检测PbQSOX蛋白在伯氏疟原虫中的表达阶段与表达特点。结果生物信息学分析发现PbQSOX蛋白存在信号肽,不存在跨膜区,蛋白均在细胞膜外表达。经PCR鉴定,PbQSOX-HA标签型打靶质粒与伯氏疟原虫同源重组正确,并成功获得了PbQSOX-HA标签型疟原虫及纯化的PbQSOX-HA标签型裂殖体、配子体与动合子。蛋白质印迹法检测显示PbQSOX蛋白主要在配子体与动合子阶段表达,间接免疫荧光实验结果显示PbQSOX表达于配子体、雄配子、合子、retort与动合子表面。结论PbQSOX是伯氏疟原虫在有性生殖阶段表达的蛋白,主要表达于配子体、雄配子、合子、retort与动合子表面。展开更多
基金supported by the Guangxi Academy of Agricultural Sciences Foundation,China(2015JZ08 and 2015YT57)the Guangxi Sciences Foundation,China(2011GXNSFA018079)+1 种基金the Modern Agro-industry Technology Research System,China(CARS-14-19)the National Natural Science Foundation of China(31160294 and 31240059)
文摘AIIopolyploidy has played an important role in plant evolution and heterosis. Recent studies indicate that the process of wide hybridization and （or） polyploidization may induce rapid and extensive genetic and epigenetic changes in some plant species. To better understand the allopolyploidy evolutionism and the genetic mechanism of Arachis interspecific hybridization, this study was conducted to monitor the gene expression variation by cDNA start codon targeted polymorphism （cDNA-SCoT） and cDNA high-frequency oligonucleotide-targeting active gene （cDNA-HFO-TAG） techniques, from the hybrids （F1） and newly synthesized allopolyploid generations （S0-$3） between tetraploid cultivated peanut Zhongkaihua 4 with diploid wild one Arachis doigoi. Rapid and considerable gene expression variations began as early as in the FI hybrid or immediately after chromosome doubling. Three types of gene expression changes were observed, including complete silence （gene from progenitors was not expressed in all progenies）, incomplete silence （gene expressed only in some progenies） and new genes activation. Those silent genes mainly involved in RNA transcription, metabolism, disease resistance, signal transduction and unknown functions. The activated genes with known function were almost retroelements by cDNA-SCoT technique and all metabolisms by cDNA-HFO-TAG. These findings indicated that interspecific hybridization and ploidy change affected gene expression via genetic and epigenetic alterations immediately upon allopolyploid formation, and some obtained transcripts derived fragments （TDFs） probably could be used in the research of molecular mechanism of Arachis allopolyploidization which contribute to thwe genetic diploidization of newly formed allopolyploids. Our research is valuable for understanding of peanut evolution and improving the utilization of putative and beneficial genes from the wild peanut.
基金a grant from the National Natural Science Foundation of China(No.30270734)
文摘Vascular endothelial growth factor （VEGF） is an angiogenic regulator that stimulates endothelial cell migration, proliferation, and angiogenesis. VEGF gene therapy is a new promising approach to induce therapeutic angiogenesis for the treatment of ischemic myocardial and limb diseases. Recently, clinical studies have demonstrated successful outcomes using plasmids, retroviruses and adenoviruses.l-3 But the safety of those vectors is poor, which has become a serious concern. Besides immunogenicity caused by viral vectors, a further problem is that viral vectors show a preference to integrate into the transcription or control region of active genes, which may induce tumors and other disorders.
文摘The rapid development of crops with multiple transgenic traits arouses the need for an efficient system for creating stacked cultivars. Most major crops rely on classical breeding to introgress the transgene from a laboratory variety to the numerous cultivars adapted to different growing regions. Even with vegetative propagated crops, genetic crosses are conducted during varietal improvement prior to vegetative cloning. The probability to assort the ＇x＇ number of transgenic loci into a single genome may seem trivial, （~）x for a diploid species, but given the ＇y＇ number of other nontransgenic traits that breeders also need to assemble into the same genome, the （~）~＊y probability for a ＇breeding stack＇ could quickly make the line conversion process unmanageable. Adding new transgenes onto existing transgenic varieties without creating a new segregating locus would require site-specific integration of new DNA at the existing transgenic locus. Here, we tested a recombinase-mediated gene-stacking scheme in tobacco. Sequential site-specific inte- gration was mediated by the mycobacteriophage Bxbl integrase-catalyzed recombination between attP and attB sites. Transgenic DNA no longer needed after integration was excised by Cre recombinase-mediated recombination of Iox sites. Site-specific integration occurred in -10% of the integration events, with half of those events usable as substrates for a next round of gene stacking. Among the site-specific integrants, however, a third experienced gene silencing. Overall, precise structure and reproducible expression of the sequentially added triple traits were obtained at an overall rate of -3% of the transformed clones--a workable frequency for the development of commercial cultivars. Moreover, since nei- ther the Bxbl-att nor the Cre-lox system is under patent, there is freedom to operate,
文摘目的观察伯氏疟原虫静息巯基氧化酶(PbQSOX)的表达阶段及表达特点。方法分别采用SignalP-5.0 Server与TMHMM Server 2.0在线软件对PbQSOX蛋白的信号肽与跨膜区进行预测分析。利用同源重组技术,将PbQSOX-HA标签型打靶质粒经限制性内切酶NotⅠ酶切使其线性化,将线性化的质粒电转染至伯氏疟原虫株内并感染小鼠。经乙胺嘧啶筛选耐药型疟原虫血症小鼠,取小鼠外周血进行PCR鉴定,获取PbQSOX-HA标签型疟原虫。培养纯化裂殖体、配子体与动合子阶段的PbQSOX-HA标签型疟原虫,采用蛋白质印迹法与间接免疫荧光实验检测PbQSOX蛋白在伯氏疟原虫中的表达阶段与表达特点。结果生物信息学分析发现PbQSOX蛋白存在信号肽,不存在跨膜区,蛋白均在细胞膜外表达。经PCR鉴定,PbQSOX-HA标签型打靶质粒与伯氏疟原虫同源重组正确,并成功获得了PbQSOX-HA标签型疟原虫及纯化的PbQSOX-HA标签型裂殖体、配子体与动合子。蛋白质印迹法检测显示PbQSOX蛋白主要在配子体与动合子阶段表达,间接免疫荧光实验结果显示PbQSOX表达于配子体、雄配子、合子、retort与动合子表面。结论PbQSOX是伯氏疟原虫在有性生殖阶段表达的蛋白,主要表达于配子体、雄配子、合子、retort与动合子表面。
