Long-term experimental evolution reveals purifying selection on piRNA-mediated control of transposable element expression.
Long-term experimental evolution reveals purifying selection on piRNA-mediated control of transposable element expression.
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DOI：
10.1186/s12915-020-00897-y
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发表时间：
2020-11-06
期刊：
影响因子：
5.4
通讯作者：
Sarkies P
中科院分区：
文献类型：
--
作者：
Bergthorsson U;Sheeba CJ;Konrad A;Belicard T;Beltran T;Katju V;Sarkies P
转座元件(TES)是真核生物基因组中几乎普遍存在的成分。在动物中，Piwi相互作用小RNA(PiRNAs)和抑制性染色质经常在阻止TE转录从而限制TE活性方面发挥关键作用。然而，TE的含量在真核生物中差异很大，而且TE活动和TE沉默在进化过程中的动态尚不清楚。在这里，我们使用实验进化的线虫种群来研究409代线虫TE表达的动态。实验种群以1、10和100个个体的种群规模进化，以操纵自然选择相对于遗传漂移的效率。我们证明相对于祖先群体，TE的表达增加，其中最大的增加发生在最小的群体中。我们发现，基因组活动区TES的转录激活与piRNA介导的沉默失败有关，而抑制染色质区域的去沉默TES保留了小RNA。此外，我们发现周围区域的序列背景影响TES通过小RNA介导的沉默失败而失去沉默的倾向。我们的结果表明，线虫的自然选择负责维持低水平的TE表达，并为相关的表观基因组特征提供了新的见解。
Transposable elements (TEs) are an almost universal constituent of eukaryotic genomes. In animals, Piwi-interacting small RNAs (piRNAs) and repressive chromatin often play crucial roles in preventing TE transcription and thus restricting TE activity. Nevertheless, TE content varies widely across eukaryotes and the dynamics of TE activity and TE silencing across evolutionary time is poorly understood. Here, we used experimentally evolved populations of C. elegans to study the dynamics of TE expression over 409 generations. The experimental populations were evolved at population sizes of 1, 10 and 100 individuals to manipulate the efficiency of natural selection versus genetic drift. We demonstrate increased TE expression relative to the ancestral population, with the largest increases occurring in the smallest populations. We show that the transcriptional activation of TEs within active regions of the genome is associated with failure of piRNA-mediated silencing, whilst desilenced TEs in repressed chromatin domains retain small RNAs. Additionally, we find that the sequence context of the surrounding region influences the propensity of TEs to lose silencing through failure of small RNA-mediated silencing. Our results show that natural selection in C. elegans is responsible for maintaining low levels of TE expression, and provide new insights into the epigenomic features responsible.
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影响因子：
64.5
作者：
Ashe A;Sapetschnig A;Weick EM;Mitchell J;Bagijn MP;Cording AC;Doebley AL;Goldstein LD;Lehrbach NJ;Le Pen J;Pintacuda G;Sakaguchi A;Sarkies P;Ahmed S;Miska EA
通讯作者：
Miska EA
影响因子：
3.4
作者：
Fontenla S;Rinaldi G;Smircich P;Tort JF
通讯作者：
Tort JF
影响因子：
4
作者：
Carelli, Francesco N.;Sharma, Garima;Ahringer, Julie
通讯作者：
Ahringer, Julie
DOI：
10.1073/pnas.1608162113
发表时间：
2016-11-08
影响因子：
11.1
作者：
Evans, Kenneth J.;Huang, Ni;Ahringer, Julie
通讯作者：
Ahringer, Julie
影响因子：
64.5
作者：
Frøkjær-Jensen C;Jain N;Hansen L;Davis MW;Li Y;Zhao D;Rebora K;Millet JRM;Liu X;Kim SK;Dupuy D;Jorgensen EM;Fire AZ
通讯作者：
Fire AZ