负链 DNA 合成
中文名称
通路描述
在逆转录的第一部分中，负链合成涉及以 HIV 基因组 RNA 为模板合成与其互补的 DNA 链，并使用宿主细胞中的赖氨酸 tRNA 作为引物。合成分为两个离散步骤，其间由链转移事件隔开。随着负链 DNA 的合成，病毒基因组 RNA 也在几个离散步骤中被降解。病毒 RNA 中的两个特定多聚嘌呤序列（PPT 序列），即位于 pol 基因（中央或 cPPT）内以及位于 U3 序列之前（3' PPT），在降解过程中被保留，并作为合成与负链互补的 DNA（即正链合成）的引物。在正链合成期间，Preston 等人观察到在细胞游离系统和培养中的感染病毒中均存在低频的正链起始位点（Klarman 等，1997）。DNA 合成和 RNA 降解活性均由 HIV-1 逆转录酶（RT）异二聚体催化。
英文描述
Minus-strand DNA synthesis In the first part of reverse transcription, minus-strand synthesis, a DNA strand complementary to the HIV genomic RNA is synthesized, using the viral RNA as a template and a host cell lysine tRNA molecule as primer. The synthesis proceeds in two discrete steps, separated by a strand transfer event. As minus strand DNA is synthesized, the viral genomic RNA is degraded, also in several discrete steps. Two specific polypurine tracts (PPT sequences) in the viral RNA, one within the pol gene (central or cPPT) and one immediately preceding the U3 sequence (3' PPT) are spared from degradation and serve to prime synthesis of DNA complementary to the minus strand (plus-strand synthesis). During plus-strand synthesis, Preston and colleagues observed secondary sites of plus-strand initiation at low frequency both in the cell-free system and in cultured virus (Klarman et al., 1997). Both DNA synthesis and RNA degradation activities are catalyzed by the HIV-1 reverse transcriptase (RT) heterodimer.
所含基因
2 个基因