！！！所有病毒都是从一个祖先进化来的...！！！

liver411

这是一个非常不错的文章．我试着翻译第一段，大家帮忙可以供大家阅读．它是讲病毒复制时＂信号ＲＮＡ＂的特性的．谢谢先．



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所有病毒都是从一个祖先进化而来，这是近日科学家对他们的新发现所做的结论，包括艾滋病毒，肝炎病毒，甚至感冒病毒都具有同样的迹象表明／支持这一发现．此发现刊登在＂分子细胞杂志～Molecular Cell＂上．文章指出以前认为每种病毒都具有各自的特性和进化性属于不同类别，但是事实上并不是这样．发现将改变人们对药物的研制方向．



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All Viruses Evolved from Common Ancestor

March 26, 2002 8:10 CDT



Scientists are discovering, much to their surprise, that broad classes of viruses, including those that can lead to AIDS, hepatitis, and even the common cold - have enough similar traits to suggest that they all evolved from a common ancestor. Details of the discovery are reported in Molecular Cell. The evidence links together groups of viruses that were once believed to be functionally and evolutionarily different. The discovery could lead to new treatments for many different virus-related illnesses.



"Recognition of these links means that principles learned from a variety of virus systems now can be used to illuminate many others, allowing integration and generalization of knowledge across a wide range of important pathogens," said Paul Ahlquist of the Howard Hughes Medical Institute at the University of Wisconsin-Madison and study's author. He says the results indicate that the viruses cause ailments as diverse as the common cold, West Nile, hepatitis C, foot and mouth disease, and that many other viruses are probably functionally and evolutionarily related to HIV.



Ahlquist was surprised by the finding because many of the viruses responsible for these illnesses were believed to reproduce in such different ways from one another that they seemed completely unrelated. There are six major classifications, and each differs in important and fundamental ways, says Ahlquist. Each represents major evolutionary lineages. "In each of these classes, there are important pathogens, and in each of these six classes there is lots of different biology."



Ahlquist and his coauthors Michael Schwartz, Jianbo Chen, Michael Janda, Michael Sullivan and Johan den Boon worked with a model virus to show that key features of replication are the same in three of the six broad classes of viruses. Ahlquist says that they found that while the viruses in these three groups build different structures to move between host cells, the basic mechanisms in their replication are the same.



Viruses are generally relatively simple organisms made up of genetic material -- RNA or DNA -- packed inside a protein coat. They reproduce and pass along their genes through the reproductive machinery of the cells they invade to make virions, infectious particles that infect other cells.



The parallel features found by the researchers concern the mechanisms the viruses use to replicate their genetic information after they take over the cells they infect. Some of the viruses replicate by switching their genes between RNA and DNA, while others store and replicate their genes only as RNAs. One thing they all have in common though, is that each virus passes on its genome through an intermediate stage of a particular kind of RNA - messenger RNA.



"This viral messenger RNA has two distinct functions," said Ahlquist. "It is used by normal cellular machinery as a template to synthesize viral proteins, and by virus-induced machinery as a template to replicate the viral genome."



Another common feature is that this viral genetic template, the messenger RNA, always is sequestered inside a compartment generated within newly infected cells by the invading virus.



"This new virus-induced compartment, in which the virus genome is reserved and copied, shows surprising similarities across these different virus groups." The reproductive workings of viruses appear to be extremely complicated since they have evolved subtle ways of disguising themselves against the immune defenses of their hosts. Ahlquist says that figuring out the similarities makes it is possible to generalize knowledge across broad classes of viruses.



The researchers reported that the three major virus groupings of viruses that fall into this category include:



-- Positive strand RNA viruses, which includes cancer-causing hepatitis C, viruses that cause the common cold and many others.



-- Reverse transcribing viruses, which include HIV, the virus that causes AIDS.



-- Double stranded RNA viruses, a grouping that includes rotavirus, a virus that kills about one million children a year in developing countries.



These three groupings make up over half of the world's known virus families. "These results have added considerably to our understanding of these viruses, and any new basic knowledge is useful in control," Ahlquist said. "If you know the machinery, you know where to throw the wrench to mess it up."



Source: University of Wisconsin-Madison



Cosmiverse Staff Writer



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Mike

请英文好的战友翻译一下.

medline

背景，名词解释， mRNA ,信使RNA 在生物细胞内，　信使ＲＮＡ作为模板，　细胞内的机器以信使RNA为模板（也就是模子）用来合成蛋白质，但这篇文章发现，病毒的mRNA不但能作为合成蛋白质的模板，还能作为病毒复制的中间体模板 ----------------------------------------------------- 这篇文章对研究抗病毒药物有指导性意义． 我来意译一些． －－－－－－－－－－－－－－－－－－－－－ 病毒共分为六大类． 这篇文章的研究表明，　其中有3类的复制机制是相类似的．也许是从一个祖先进化来的． 这３类病毒为 1:正链RNA病毒，包括丙肝病毒，流感病毒 2:逆转录病毒，包括艾滋病病毒 3:双链RNA病毒，　包括轮状病毒 这篇文章，他们复制的基本机制都是相同的，而且很特别 具有两个共同特点： 一个共同特点是：每个病毒通过一个中间期，一种特别的mRNA,把基因组信息传递．＂这种mRNA有两种功能， １被体细胞的机器用作模板合成蛋白质(这一点和体细胞一样)， ２被病毒特有的机器用作模板来合成病毒的基因组（这一点完全不同于体细胞） 另一个共同的特点是，这种病毒模板，总是集中在侵入病毒在新感染的体细胞中诱导形成的一个区域中（这一点完全不同于体细胞）． －－－－－－－－－－－－－－－－－－－－－ 意义，　发现病毒复制的不同于体细胞的一种共同特点，有可能以这个为理论基础，研究出抗病毒药物． －－－－－－－－－－－－－－－－－－－－－－－－－ 翻译中掺入很多个人评论， 但对上文的两个发现则是直译 请指正． 另外． [乙肝病毒为逆转录病毒，属于上面的第二类，谢谢liver411指正，medline在此修正］ [ 此消息由 medline 在 2002-03-28.18:34:06 编辑过 ]

liver411

谢谢medline, 好快. 乙肝病毒应该是属于第二种病毒, 和艾滋病毒一样, 反向录制; 查了一下也带有mRNA. 乙肝病毒复制过程: First the virus attaches to a liver cells membrane. 病毒附带在肝脏细胞上 The virus is then transported into the liver cell 进入细胞 The core particle then releases it's contents of DNA and DNA polymerase into the liver cell nucleus. 病毒核心释放DNA和DNA链条进入肝脏细胞核 Once within the cell nucleus the hepatitis B DNA causes the liver cell to produce, via messenger RNA; surface (HBs) proteins, the core (HBc) protein, DNA polymerase, the HBe protein, HBx protein and possibly other as yet undetected proteins and enzymes. DNA polymerase causes the liver cell to make copies of hepatitis B DNA from messenger RNA. 当HBV DNA进入细胞核, 通过信使RNA; 制造表体蛋白, 核心蛋白, DNA链条, e蛋白, x蛋白, 和一些目前不知晓的蛋白, 酶等. DNA链条使肝脏细胞, 从mRNA带给的信息, 复制DNA. The cell then assembles 'live' copies of the virus. Via the above processes, versions of the hepatitis B virus are constructed by the liver cell . 肝脏细胞然后组合复制的病毒. However because of the excess numbers of surface proteins produced many of these stick together to form small spheres and chains. These can give a characteristic "ground glass" appearance to blood samples seen under a microscope. 多余出来的表体蛋白造成球型, 链型沾粘物~俗称"园玻璃" 可在电镜中看到. The copies of the virus and excess surface antigen are released from the liver cell membrane into the blood stream and from there can infect other liver cells and thus replicate effectively. 复制出来的病毒和多余出来的表体抗原(蛋白)从肝脏细胞中释放出来进入血中, 从而可以再对其它的肝脏细胞感染.

medline

谢谢liver411指正。

HBV 是逆转录病毒，属于第二类。



Unexpected Links Found Between Many RNA Viruses





  

"Over the long term, understanding that these viruses share common properties should enable new antiviral strategies, and allow strategies developed for one type of virus to be generalized to the others," said HHMI investigator Paul Ahlquist.





March 23, 2002— Howard Hughes Medical Institute researchers have discovered surprising parallels in the way that three different classes of RNA viruses replicate. The discovery suggests that there might one day be a common strategy to kill many different RNA viruses, a group that includes HIV, rotavirus, hepatitis C and polio viruses.



In an article published in the March 2002, issue of the journal Molecular Cell, HHMI investigator Paul Ahlquist and colleagues at the University of Wisconsin at Madison described the parallels among “positive-strand” RNA viruses ([+]RNA), retroviruses and double-stranded RNA viruses. Since these viruses cause a broad range of diseases, the scientists believe that identifying a common link between the viruses may be the first step to devising more general virus control or treatment strategies.



Positive-strand RNA viruses first copy their RNA genome into a negative-strand intermediate RNA before replicating their RNA. These viruses cause hepatitis C, encephalitis, hemorrhagic fevers, polio, foot and mouth disease, the common cold, and many other illnesses.



Retroviruses and other reverse-transcribing viruses, which include HIV and hepatitis B, copy their RNA into DNA before replicating their genome back into RNA. Double-stranded RNA viruses — which include the rotavirus that kills about one million children a year in developing countries — separate their strands and copy one strand to replicate.



Ahlquist and his colleagues discovered that, although the viruses seem to take distinct routes to replication, all three types use related pathways and structures to replicate their genes. By linking three of the six major classes of viruses, the results offer a significant unification within the field of virology.



“The multiple functional parallels we have found in replication mechanisms reveal unexpected links among these viruses,” said Ahlquist. “Recognition of these links means that principles learned from a variety of virus systems can be used to illuminate many others, allowing integration and generalization of knowledge across a wide range of important viruses. Among other benefits, this should facilitate improved strategies for virus control.”



Ahlquist and his colleagues based their insights on studies of a model [+]RNA virus called brome mosaic virus (BMV), which they induced to infect yeast. In studying BMV replication in yeast, Ahlquist and his colleagues examined the function of two proteins — called 1a and 2a polymerase – which are important in viral replication. Their electron microscopy of labeled viral components, and additional genetic and biochemical studies, revealed that large numbers of 1a proteins form partially budded spherules containing the viral RNA and 2a polymerase, which is responsible for replicating the viral RNA. These spherules are formed in the membranes of an internal cell structure called the endoplasmic reticulum, which is the site of BMV viral replication.



Their studies also showed that this [+]RNA replication machinery strongly paralleled that of retroviruses. In retroviruses, a protein called Gag forms a similar budding structure called a capsid that envelops the viral RNA and the Pol enzyme — a reverse transcriptase that copies RNA to DNA. These capsids are formed in a structure called the plasma membrane, where retroviral replication takes place. This replication machinery is triggered by an RNA packaging signal that parallels the action of the signal in BMV.



These same principles of sequestering a viral RNA intermediate and its polymerase, plus other features of [+]RNA viruses, are shared with double-stranded RNA viruses, Ahlquist said.



According to Ahlquist, their findings and complementary findings of other scientists suggest that all three classes of viruses evolved from a common ancestor. For example, he said, besides the parallels he and his colleagues have just discovered, RNA replication in both retroviruses and BMV is “primed” by a specialized RNA called tRNA.



“We do not want to suggest that these discoveries will yield new treatments for viruses tomorrow,” he said. “However, over the long term, understanding that these viruses share common properties should enable new antiviral strategies, and allow strategies developed for one type of virus to be generalized to the others.