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851.
Most foldback elements are defective due to the lack of coding sequences but some are associated with coding sequences and may represent the entire element. This is the case of the NOF sequences found in the FB of Drosophila melanogaster, formerly considered as an autonomous TE and currently proposed as part of the so-called FB-NOF element, the transposon that would be complete and fully functional. NOF is always associated with FB and never seen apart from the FB inverted repeats (IR). This is the reason why the FB-NOF composite element can be considered the complete element. At least one of its ORFs encodes a protein that has always been considered its transposase, but no detailed studies have been carried out to verify this. 相似文献
852.
The endosymbiotic theory postulates that many genes migrated from endosymbionts to the nuclear genomes of their hosts. Some migrated genes lack presequences directing proteins to mitochondria, and their mitochondrial targeting signals appear to be inscribed in the core coding regions as internal targeting signals (ITSs). ITSs may have evolved after sequence transfer to nuclei or ITSs may have pre-existed before sequence transfer. Here, we report the molecular cloning of a sugar beet gene for ribosomal protein S19 (Rps19; the first letter is capitalized when the gene is a nuclear gene). We show that sugar beet Rps19 (BvRps19) is an ITS-type gene. Based on amino-acid sequence comparison, dicotyledonous rps19s (the first letter is lower-cased when the gene is a mitochondrial gene), such as tobacco rps19 (Ntrps19), resemble an ancestral form of BvRps19. We investigated whether differences in amino-acid sequences between BvRps19 and Ntrps19 were involved in ITS evolution. Analyses of the intracellular localization of chimaeric GFP-fusion proteins that were transiently expressed in Welsh onion cells showed that Ntrps19-gfp was not localized in mitochondria. When several BvRps19-type amino acid substitutions, none of which was seen in any other angiosperm rps19, were introduced into Ntrps19-gfp, the modified Ntrps19-gfp became localized in mitochondria, supporting the notion that an ITS in BvRps19 evolved following sequence transfer to nuclei. Not all of these substitutions were seen in other ITS-type Rps19s, suggesting that the ITSs of Rps19 are diverse. 相似文献
853.
854.
猪流行性腹泻病毒反向遗传操作技术及其应用 总被引:2,自引:0,他引:2
猪流行性腹泻病毒(PEDV)是引起猪(特别是新生仔猪)急性、高度传染性消化道疾病的主要病原之一;2010年底以来,猪流行性腹泻(PED)的再次暴发给我国乃至全球养猪业造成了巨大经济损失。最近,研究者已先后建立了基于靶向RNA重组技术、细菌人工染色体(BAC)载体系统和体外连接技术的PEDV反向遗传学操作技术,为PEDV编码的蛋白质的功能、致病机制以及新型疫苗的研发开辟了新的思路。本文对PEDV反向遗传操作技术的研究进展及其在PEDV胰酶依赖性、S蛋白和ORF3蛋白的功能以及新一代疫苗研制等方面的应用现状进行了综述与展望。 相似文献
855.
The rat GPRC6A: cloning and characterization 总被引:2,自引:0,他引:2
Wellendorph P Burhenne N Christiansen B Walter B Schmale H Bräuner-Osborne H 《Gene》2007,396(2):257-267
856.
鉴于琼脂糖凝胶电泳分析方法的准确、快速、简便等特性,优化后可以做为检出COVID-19病原的新方法。在不影响结果判读的情况下,通过对扩增时间及检测样本浓度进行优化,以达到预期目的。结果表明,检测SARS-CoV-2的最优反应程序为94℃预变性3 min;94℃变性时间、56℃退火时间及72℃延伸时间均降至5 s,且进行35个循环;最后72℃孵育5 min,最优模板用量比例(初始值设为4 ng)下限调整在(1:1 000)~(1:5 000)范围内。阳性样本测试结果符合预期。建立了一种简便、省时,适用于检测低载量病毒样本的新方法,为临床提供诊断参考。 相似文献
857.
Wei Wang Wenkun Fu Dequan Pan Linli Cai Jianghui Ye Jian Liu Che Liu Yuqiong Que Ningshao Xia Hua Zhu Tong Cheng 《中国病毒学》2017,32(5):387-395
Varicella-zoster virus (VZV) is a neurotropic alphaherpesvirus that causes chickenpox and shingles. ORF7 is an important virulence determinant of VZV in both human skin and nerve tissues, however, its specific function and involved molecular mechanism in VZV pathogenesis remain largely elusive. Previous yeast two-hybrid studies on intraviral protein-protein interaction network in herpesviruses have revealed that VZV ORF7 may interact with ORF53, which is a virtually unstudied but essential viral protein. The aim of this study is to identify and characterize VZV ORF53, and to investigate its relationship with ORF7. For this purpose, we prepared monoclonal antibodies against ORF53 and, for the first time, characterized it as a ~40 kDa viral protein predominantly localizing to the trans-Golgi network of the infected host cell. Next, we further confirmed the interaction between ORF7 and ORF53 by co-immunoprecipitation and co-localization studies in both plasmid-transfected and VZV-infected cells. Moreover, interestingly, we found that ORF53 lost its trans-Golgi network localization and became dispersed in the cytoplasm of host cells infected with an ORF7-deleted recombinant VZV, and thus ORF7 seems to play a role in normal subcellular localization of ORF53. Collectively, these results suggested that ORF7 and ORF53 may function as a complex during infection, which may be implicated in VZV pathogenesis.
相似文献
858.
Diemer C Schneider M Seebach J Quaas J Frösner G Schätzl HM Gilch S 《Journal of molecular biology》2008,376(1):23-34
The epidemic outbreak of severe acute respiratory syndrome (SARS) in 2003 was caused by a novel coronavirus (CoV), designated SARS-CoV. The RNA genome of SARS-CoV is complexed by the nucleocapsid protein (N) to form a helical nucleocapsid. Besides this primary function, N seems to be involved in apoptotic scenarios. We show that upon infection of Vero E6 cells with SARS-CoV, which elicits a pronounced cytopathic effect and a high viral titer, N is cleaved by caspases. In contrast, in SARS-CoV-infected Caco-2 cells, which show a moderate cytopathic effect and a low viral titer, this processing of N was not observed. To further verify these observations, we transiently expressed N in different cell lines. Caco-2 and N2a cells served as models for persistent SARS-CoV infection, whereas Vero E6 and A549 cells did as prototype cell lines lytically infected by SARS-CoV. The experiments revealed that N induces the intrinsic apoptotic pathway, resulting in processing of N at residues 400 and 403 by caspase-6 and/or caspase-3. Of note, caspase activation is highly cell type specific in SARS-CoV-infected as well as transiently transfected cells. In Caco-2 and N2a cells, almost no N-processing was detectable. In Vero E6 and A549 cells, a high proportion of N was cleaved by caspases. Moreover, we examined the subcellular localization of SARS-CoV N in these cell lines. In transfected Vero E6 and A549 cells, SARS-CoV N was localized both in the cytoplasm and nucleus, whereas in Caco-2 and N2a cells, nearly no nuclear localization was observed. In addition, our studies indicate that the nuclear localization of N is essential for its caspase-6-mediated cleavage. These data suggest a correlation among the replication cycle of SARS-CoV, subcellular localization of N, induction of apoptosis, and the subsequent activation of caspases leading to cleavage of N. 相似文献
859.
为了探讨猪繁殖与呼吸综合征病毒(PRRSV)ORF5基因编码的GP5蛋白和ORF6编码的M蛋白体外共表达特性,分别构建了PRRSV ORF5、ORF6单基因或双基因共表达的真核表达质粒pCI-ORF5、pCI-ORF6和pCI-ORF5/ORF6,转染BHK-21细胞,Western blot检测证实共表达的GP5和M蛋白能够形成异源二聚体。同时,以绿色荧光蛋白(EGFP)和红色荧光蛋白(RFP)为示踪,发现当ORF5-EGFP和ORF6-RFP共表达时,能促进GP5蛋白从内质网向高尔基体转运,提示GP5-M异源二聚体的形成可能与GP5蛋白的翻译后修饰、转运、定位有关。 相似文献