Knisbacher Binyamin A, Levanon Erez Y
The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel.
Ann N Y Acad Sci. 2015 Apr;1341:115-25. doi: 10.1111/nyas.12713. Epub 2015 Feb 26.
Genome evolution is commonly viewed as a gradual process that is driven by random mutations that accumulate over time. However, DNA- and RNA-editing enzymes have been identified that can accelerate evolution by actively modifying the genomically encoded information. The apolipoprotein B mRNA editing enzymes, catalytic polypeptide-like (APOBECs) are potent restriction factors that can inhibit retroelements by cytosine-to-uridine editing of retroelement DNA after reverse transcription. In some cases, a retroelement may successfully integrate into the genome despite being hypermutated. Such events introduce unique sequences into the genome and are thus a source of genomic innovation. adenosine deaminases that act on RNA (ADARs) catalyze adenosine-to-inosine editing in double-stranded RNA, commonly formed by oppositely oriented retroelements. The RNA editing confers plasticity to the transcriptome by generating many transcript variants from a single genomic locus. If the editing produces a beneficial variant, the genome may maintain the locus that produces the RNA-edited transcript for its novel function. Here, we discuss how these two powerful editing mechanisms, which both target inserted retroelements, facilitate expedited genome evolution.
基因组进化通常被视为一个渐进的过程，由随时间积累的随机突变驱动。然而，已经鉴定出DNA和RNA编辑酶，它们可以通过主动修饰基因组编码信息来加速进化。载脂蛋白B mRNA编辑酶，即催化多肽样（APOBECs），是强大的限制因子，可在逆转录后通过对逆转录元件DNA进行胞嘧啶到尿嘧啶的编辑来抑制逆转录元件。在某些情况下，尽管逆转录元件发生了高度突变，但它仍可能成功整合到基因组中。此类事件会将独特序列引入基因组，因此是基因组创新的一个来源。作用于RNA的腺苷脱氨酶（ADARs）催化双链RNA中的腺苷到次黄嘌呤的编辑，双链RNA通常由反向排列的逆转录元件形成。RNA编辑通过从单个基因组位点产生许多转录变体，赋予转录组可塑性。如果编辑产生有益变体，基因组可能会保留产生RNA编辑转录本的位点以发挥其新功能。在这里，我们讨论这两种强大的编辑机制如何通过靶向插入的逆转录元件促进加速的基因组进化。
