Human Immunodeficiency Virus type-1 reverse transcriptase exists as post-translationally modified forms in virions and cells
Human Immunodeficiency Virus type-1 reverse transcriptase exists as post-translationally modified forms in virions and cells
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DOI：
10.1186/1742-4690-5-115
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发表时间：
2008-12-18
期刊：
影响因子：
3.3
通讯作者：
Li, Peng
中科院分区：
文献类型：
--
作者：
Davis, Adam J.;Carr, Jillian M.;Li, Peng
背景资料：HIV-1逆转录酶（RT）是由p66和p51亚基组成的异源二聚体，负责将病毒RNA基因组逆转录为DNA。RT在体外可以被后修饰，这可能是调节RT活性的重要机制。结果：p66和p51 RT亚基的主要亚型为p66（8.44）和p51（8.31），其等电点分别为8.44和8.31。相同的主要同种型存在于病毒体、病毒感染的细胞裂解物和细胞内逆转录复合物（RTC）中，并且它们在RTC中的存在表明这些可能是在逆转录中起作用的形式。还观察到几种次要RT亚型。观察到的RT同种型的pI不同于理论上未修饰RT的pI（p66（8.53）和p51（8.60）），表明病毒体和细胞中的大多数RT蛋白是后修饰的。p66（8.44）和p51（8.31）的修饰彼此不同，表明不同RT亚基的选择性修饰。RT亚型对磷酸酶处理的敏感性表明，这些修饰中的一些是由于磷酸化。去磷酸化，但是，在体外RT活性与病毒粒子，感染的细胞或RTCs没有影响，这表明磷酸化的异构体不作出重大贡献RT activityin a vitro assay.Conclusion：相同的主要异构体的p66和p51 RT中发现病毒粒子，感染的细胞和RTC的，这两个亚基是post-acetylated修改。RT的这种翻译后修饰对于RT在细胞内的功能可能是重要的。
Background: HIV-1 reverse transcriptase (RT) is a heterodimer composed of p66 and p51 subunits and is responsible for reverse transcription of the viral RNA genome into DNA. RT can be post-translationally modified in vitro which may be an important mechanism for regulating RT activity. Here we report detection of different p66 and p51 RT isoforms by 2D gel electrophoresis in virions and infected cells.Results: Major isoforms of the p66 and p51 RT subunits were observed, with pI's of 8.44 and 8.31 respectively (p66(8.44) and p51(8.31)). The same major isoforms were present in virions, virus-infected cell lysates and intracellular reverse transcription complexes (RTCs), and their presence in RTCs suggested that these are likely to be the forms that function in reverse transcription. Several minor RT isoforms were also observed. The observed pIs of the RT isoforms differed from the pI of theoretical unmodified RT (p66(8.53) and p51(8.60)), suggesting that most of the RT protein in virions and cells is post-translationally modified. The modifications of p66(8.44) and p51(8.31) differed from each other indicating selective modification of the different RT subunits. The susceptibility of RT isoforms to phosphatase treatment suggested that some of these modifications were due to phosphorylation. Dephosphorylation, however, had no effect on in vitro RT activity associated with virions, infected cells or RTCs suggesting that the phospho-isoforms do not make a major contribution to RT activity in an in vitro assay.Conclusion: The same major isoform of p66 and p51 RT is found in virions, infected cells and RTC's and both of these subunits are post-translationally modified. This post-translational modification of RT may be important for the function of RT inside the cell.