Yoth Marianne, Jensen Silke, Brasset Emilie
iGReD, CNRS, INSERM, Faculté de Médecine, Université Clermont Auvergne, 63000 Clermont-Ferrand, France.
Biology (Basel). 2022 May 6;11(5):710. doi: 10.3390/biology11050710.
Transposable elements (TEs) are mobile DNA sequences that can jump from one genomic locus to another and that have colonized the genomes of all living organisms. TE mobilization and accumulation are an important source of genomic innovations that greatly contribute to the host species evolution. To ensure their maintenance and amplification, TE transposition must occur in the germ cell genome. As TE transposition is also a major threat to genome integrity, the outcome of TE mobility in germ cell genomes could be highly dangerous because such mutations are inheritable. Thus, organisms have developed specialized strategies to protect the genome integrity from TE transposition, particularly in germ cells. Such effective TE silencing, together with ongoing mutations and negative selection, should result in the complete elimination of functional TEs from genomes. However, TEs have developed efficient strategies for their maintenance and spreading in populations, particularly by using horizontal transfer to invade the genome of novel species. Here, we discuss how TEs manage to bypass the host's silencing machineries to propagate in its genome and how hosts engage in a fightback against TE invasion and propagation. This shows how TEs and their hosts have been evolving together to achieve a fine balance between transposition and repression.
转座元件（TEs）是可移动的DNA序列，能够从一个基因组位点跳跃到另一个位点，并且已经在所有生物体的基因组中存在。TE的移动和积累是基因组创新的重要来源，对宿主物种的进化有很大贡献。为确保其维持和扩增，TE转座必须发生在生殖细胞基因组中。由于TE转座也是对基因组完整性的主要威胁，生殖细胞基因组中TE移动的结果可能非常危险，因为此类突变是可遗传的。因此，生物体已经开发出专门的策略来保护基因组完整性免受TE转座的影响，尤其是在生殖细胞中。这种有效的TE沉默，连同持续的突变和负选择，应该会导致基因组中功能性TE的完全消除。然而，TE已经开发出有效的策略来在种群中维持和传播，特别是通过水平转移来侵入新物种的基因组。在这里，我们讨论TE如何设法绕过宿主的沉默机制在其基因组中传播，以及宿主如何反击TE的入侵和传播。这展示了TE及其宿主如何共同进化以在转座和抑制之间实现良好的平衡。
