八段RNA的包装
中文名称
通路描述
对于包被的流感病毒要完全具有感染性，必须包含完整的八种vRNA片段。关于vRNPs包装进新组装病毒颗粒有两种模型：随机掺入模型和选择性掺入模型。随机掺入模型认为没有对哪些vRNPs进行包装的选择。假设每个vRNP被包装的概率相等，如果包装了足够的vRNPs，那么一定百分比的出芽病毒颗粒将至少获得每种基因组片段的一个拷贝。这一模型得到了证据支持，即感染性病毒颗粒可能包含超过八种vRNPs，确保病毒颗粒中一定百分比含有完整的八种vRNPs。对包装的数学分析表明，需要包装十二种RNA片段才能获得约10%的完全感染性病毒颗粒（Enami, 1991），这一数字与实验数据相符（Donald, 1954）。由于每个病毒颗粒中的RNA含量很低（估计为1-2% w/w），精确计数病毒颗粒中包装的RNA数量很困难。选择性掺入模型认为每种vRNA片段都含有独特的“包装信号”，使其能够独立作用，每种vRNA片段被选择性包装。越来越多的证据支持在基因组RNA的5'和3'端编码区内存在包装信号，除第7段外，所有片段都报告有信号（Ozawa 2007, Muramoto 2006, Fujii 2005, Fujii 2003, Watanabe 2003, Liang 2005）。虽然单个vRNP片段的包装方法尚不清楚，但已假设其通过特定的RNA-RNA或蛋白-RNA相互作用发生。这一模型也得到了显示流感颗粒中可见八个明显“点”的超薄电子显微镜图像的支持，这些点可能是病毒颗粒内的vRNPs（Noda 2006）。
英文描述
Packaging of Eight RNA Segments For a budding influenza virus to be fully infectious is it essential that it contains a full complement of the eight vRNA segments. Two different models have been proposed for packaging of the vRNPs into newly assembling virus particles; the random incorporation model and the selective incorporation model.
The random incorporation model as its name suggests proposes that there is no selection at all on which vRNPs are packaged. It is assumed that each vRNP has equal probability of being packaged, and that if enough vRNPS are packaged a particular percentage of budding virions will receive at least one copy of each genome segment. This model is supported by evidence that infectious virions may possess more than eight vRNPs assuring the presence of a full complement of eight vRNPs in a significant percentage of virus particles. Mathematical analysis of packaging suggested that twelve RNA segments would need to be packaged in order to obtain approximately 10% of virus particles that are fully infectious (Enami, 1991), a number that is compatible with experimental data (Donald, 1954). Due to the low amount of RNA per virion (estimated at 1-2% w/w), enumeration of the precise number of RNAs packaged in a virion is difficult.
The selective incorporation model, suggests that each vRNA segment contains a unique "packaging signal" allowing it to act independently, with each vRNA segment being packaged selectively. There is increasing evidence to support the theory of a packaging signal within the coding regions at both the 5' and 3' end of the genomic RNA, with signals being reported for all segments except segment 7 (Ozawa 2007, Muramoto 2006, Fujii 2005, Fujii 2003, Watanabe 2003, Liang 2005). The exact method by which individual vRNP segments are packaged is not known but it has been hypothesized to occur via specific RNA-RNA or protein-RNA interactions. This model is also supported by thin section electron microscopy images of influenza particles that show eight distinct "dots", presumably vRNPs within virus particles (Noda 2006).
The random incorporation model as its name suggests proposes that there is no selection at all on which vRNPs are packaged. It is assumed that each vRNP has equal probability of being packaged, and that if enough vRNPS are packaged a particular percentage of budding virions will receive at least one copy of each genome segment. This model is supported by evidence that infectious virions may possess more than eight vRNPs assuring the presence of a full complement of eight vRNPs in a significant percentage of virus particles. Mathematical analysis of packaging suggested that twelve RNA segments would need to be packaged in order to obtain approximately 10% of virus particles that are fully infectious (Enami, 1991), a number that is compatible with experimental data (Donald, 1954). Due to the low amount of RNA per virion (estimated at 1-2% w/w), enumeration of the precise number of RNAs packaged in a virion is difficult.
The selective incorporation model, suggests that each vRNA segment contains a unique "packaging signal" allowing it to act independently, with each vRNA segment being packaged selectively. There is increasing evidence to support the theory of a packaging signal within the coding regions at both the 5' and 3' end of the genomic RNA, with signals being reported for all segments except segment 7 (Ozawa 2007, Muramoto 2006, Fujii 2005, Fujii 2003, Watanabe 2003, Liang 2005). The exact method by which individual vRNP segments are packaged is not known but it has been hypothesized to occur via specific RNA-RNA or protein-RNA interactions. This model is also supported by thin section electron microscopy images of influenza particles that show eight distinct "dots", presumably vRNPs within virus particles (Noda 2006).
所含基因
5 个基因