Wilhelm M, Wilhelm F X
Unité Propre de Recherche 9002 du Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire et Cellulaire, Strasbourg, France.
Cell Mol Life Sci. 2001 Aug;58(9):1246-62. doi: 10.1007/PL00000937.
Retroelements are mobile genetic entities that replicate via reverse transcription of a template RNA. A key component to the life cycle of these elements is the enzyme reverse transcriptase (RT), which copies the single-stranded genomic RNA of the element into a linear double-stranded DNA that is ultimately integrated into the host genome by the element-encoded integrase. RT is a multifunctionnal enzyme which possesses RNA-dependent and DNA-dependent DNA polymerase activities as well as RNase H activity that specifically degrades the RNA strand of RNA-DNA duplexes. At some stages of the replication a strand-displacement activity of RT is also necessary. All activities are essential for the conversion of single-stranded genomic RNA into the double-stranded preintegrative DNA. This review focuses on the role of RT in the different steps of the replication process of retroelements. The features of retrotransposon replication which differ from the retroviral ones will be emphasized. In a second part of the review, the biochemical and enzymatic properties of two newly characterized retrotransposon RTs will be described. The role of the integrase domain in reverse transcriptase activity of some retroviral and retrotransposon RTs will be discussed.
逆转录元件是通过模板RNA的逆转录进行复制的可移动遗传实体。这些元件生命周期的一个关键组成部分是逆转录酶（RT），它将元件的单链基因组RNA复制成线性双链DNA，最终由元件编码的整合酶整合到宿主基因组中。RT是一种多功能酶，具有依赖RNA和依赖DNA的DNA聚合酶活性以及RNase H活性，可特异性降解RNA-DNA双链体的RNA链。在复制的某些阶段，RT的链置换活性也是必需的。所有这些活性对于将单链基因组RNA转化为双链前整合DNA都是必不可少的。本综述重点关注RT在逆转录元件复制过程不同步骤中的作用。将强调逆转座子复制与逆转录病毒复制不同的特征。在综述的第二部分，将描述两种新鉴定的逆转座子RT的生化和酶学特性。还将讨论整合酶结构域在一些逆转录病毒和逆转座子RT逆转录酶活性中的作用。
