Ordered interstrand and intrastrand DNA transfer during reverse transcription.-猫眼课题宝

逆转录期间有序链间和链内 DNA 转移。

DOI：

10.1126/science.2457948

发表时间：

1988

期刊：

Science

影响因子：

56.9

通讯作者：

中科院分区：

综合性期刊1区

文献类型：

作者：

A. Panganiban;D. Fiore

逆转录病毒包含两份正链病毒RNA基因组。为了确定这两份RNA是否都在逆转录反应中被使用，用在RNA末端两个不同位置的核苷酸序列存在差异的杂合病毒颗粒感染细胞。然后对经过一轮逆转录形成的DNA前病毒进行检测。在已鉴定的12个前病毒中，所有的都显示出长末端重复序列（LTR），只有当两份RNA模板都被用于生成负链DNA时才会出现这种情况。相比之下，在生成完全双链病毒DNA时，似乎只有一条负链DNA被用作正链DNA的模板。这些结果表明，逆转录中的第一次链转移步骤是一个分子间事件，而第二次转移是分子内事件。因此，逆转录病毒包含两份具有功能活性的RNA，并且可能两份都需要用于生成一个单一的线性DNA分子。预计在逆转录病毒感染过程中杂合体的形成会导致LTR重组体的高效产生。

Retroviruses contain two copies of the plus stranded viral RNA genome. As a means of determining whether both of these RNA's are used in the reverse transcription reaction, cells were infected with heterozygous virus particles that varied in nucleotide sequence at two separate locations at the RNA termini. The DNA proviruses formed from a single cycle of reverse transcription were then examined. Of the 12 proviruses that were characterized, all exhibited long terminal repeats (LTR's) that would be expected to arise only if both RNA templates were used for the generation of minus strand DNA. In contrast, only a single minus strand DNA appeared to be used as template for the plus strand DNA in the generation of fully double-stranded viral DNA. These results indicate that the first strand transfer step in reverse transcription is an intermolecular event while that of the second transfer is intramolecular. Thus, retroviruses contain two functionally active RNA's, and both may be required for the generation of a single linear DNA molecule. Formation of heterozygotes during retrovirus infection would be expected to result in the efficient generation of LTR recombinants.

A promoterless retroviral vector indicates that there are sequences in U3 required for 3' RNA processing.