美国康奈尔大学Cédric Feschotte课题组取得一项新突破。他们揭示转座酶捕获的脊椎动物转录因子的周期性进化。相关论文于2021年2月19日发表在《科学》杂志上。

他们显示DNA转座子通过外显子改组提供了循环供应材料来组装蛋白质编码基因。他们发现转座酶结构域已被捕获（主要是通过可变剪接），在大约3.5亿年的四足动物进化过程中，至少独立地形成了融合蛋白94次。

他们发现过量的转座酶DNA结合结构域融合到宿主调节域，尤其是与Krüppel相关框（KRAB）域，并确定了四个独立进化的KRAB-转座酶融合蛋白以序列特异性方式抑制基因表达。蝙蝠特异性KRABINER融合蛋白在全基因组范围内结合其同源转座子，并控制基因和顺式调控元件的网络。这些结果说明了转录因子及其结合位点如何出现。

据介绍，具有新型细胞功能的基因可能会通过外显子改组而进化，这可以组装出新的蛋白质结构。

附：英文原文

Title: Recurrent evolution of vertebrate transcription factors by transposase capture

Author: Rachel L. Cosby, Julius Judd, Ruiling Zhang, Alan Zhong, Nathaniel Garry, Ellen J. Pritham, Cédric Feschotte

Issue&Volume: 2021/02/19

Abstract: Genes with novel cellular functions may evolve through exon shuffling, which can assemble novel protein architectures. Here, we show that DNA transposons provide a recurrent supply of materials to assemble protein-coding genes through exon shuffling. We find that transposase domains have been captured—primarily via alternative splicing—to form fusion proteins at least 94 times independently over the course of ~350 million years of tetrapod evolution. We find an excess of transposase DNA binding domains fused to host regulatory domains, especially the Krüppel-associated box (KRAB) domain, and identify four independently evolved KRAB-transposase fusion proteins repressing gene expression in a sequence-specific fashion. The bat-specific KRABINER fusion protein binds its cognate transposons genome-wide and controls a network of genes and cis-regulatory elements. These results illustrate how a transcription factor and its binding sites can emerge.

DOI: 10.1126/science.abc6405

Source: https://science.sciencemag.org/content/371/6531/eabc6405