Taming transposable elements in vertebrates: from epigenetic silencing to domestication. Issue 6 (June 2022)

• Record Type: Journal Article
• Authors: Almeida, Miguel Vasconcelos; Vernaz, Grégoire; Putman, Audrey L.K.; Miska, Eric A.
• Is Part Of: Trends in genetics. Volume 38:Issue 6(2022)
• Page Start: 529
• Page End: 553
• Publication Date: 2022-06
• Subjects: transposable elements (TEs) -- epigenetic silencing -- genome evolution -- vertebrates -- TE domestication; Genetics -- Periodicals; 576.5
• DOI: 10.1016/j.tig.2022.02.009
• Languages: English
• ISSNs: 0168-9525

Abstract

Abstract : Transposable element (TE)-derived sequences are ubiquitous in most eukaryotic genomes known to date. Because their expression and mobility can lead to genomic instability, several pathways have evolved to control TEs. Nevertheless, TEs represent an important source of genomic novelty and are often co-opted for novel functions that are relevant for phenotypic divergence and adaptation. Here, we review how animals, in particular vertebrates, mitigate TE mobility and expression, alongside known examples of TE domestication. We argue that the next frontier is to understand the determinants and dynamics of TE domestication: how they shift from 'non-self' targets of epigenetic silencing to 'self' genetic elements. New technologies enable avenues of research that may close the gap between epigenetic silencing and domestication of TEs. Highlights: Transposable element (TE) expression and mobility are sources of genetic conflict with their host genome. But despite their primarily neutral or deleterious effects to host fitness, TEs represent an important source of evolutionary novelty. Eukaryotes have evolved an array of complex, interconnected epigenetic mechanisms to silence and control TEs: small RNAs, Krüppel-associated box (KRAB) domain-containing zinc finger proteins, DNA methylation, histone modifications, splicing inhibition, and RNA modifications. TE domestication comprises the repurposing of TE-derived sequences for functions beneficial to their host. Domesticated TEs acquired gene regulatory roles and increased transcriptomic and proteomic diversity. Epigenetic silencing influences TE domestication and mediates the emergence of novel regulatory mechanisms throughout vertebrate evolution.