Plant genomes are littered with transposable elements (TEs). Because TEs are potentially highly mutagenic, host organisms have evolved a set of defense mechanisms to recognize and epigenetically silence them. Although the maintenance of TE silencing is well studied, our understanding of the initiation of TE silencing is limited, but it clearly involves small RNAs and DNA methylation. Once TEs are silent, the silent state can be maintained to subsequent generations. However, under some circumstances, such inheritance is unstable, leading to the escape of TEs to the silencing machinery, resulting in the transcriptional activation of TEs. Epigenetic control of TEs has been found to be closely linked to many other epigenetic phenomena, such as genomic imprinting, and is known to contribute to regulation of genes, especially those near TEs. Here we review and discuss the current models of TE silencing, its unstable inheritance after hybridization, and the effects of epigenetic regulation of TEs on genomic imprinting.
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http://dx.doi.org/10.1016/j.pbi.2023.102428 | DOI Listing |
Nature
January 2025
Department of Biological Sciences, The University of Tokyo, Tokyo, Japan.
In organisms ranging from vertebrates to plants, major components of centromeres are rapidly evolving repeat sequences, such as tandem repeats (TRs) and transposable elements (TEs), which harbour centromere-specific histone H3 (CENH3). Complete centromere structures recently determined in human and Arabidopsis suggest frequent integration and purging of retrotransposons within the TR regions of centromeres. Despite the high impact of 'centrophilic' retrotransposons on the paradox of rapid centromere evolution, the mechanisms involved in centromere targeting remain poorly understood in any organism.
View Article and Find Full Text PDFBMC Genomics
December 2024
Pathology and Biomedical Science Department, University of Otago Christchurch, Christchurch, New Zealand.
Background: Anorexia nervosa (AN) is a polygenic, severe metabopsychiatric disorder with poorly understood aetiology. Eight significant loci have been identified by genome-wide association studies (GWAS) and single nucleotide polymorphism (SNP)-based heritability was estimated to be ~ 11-17, yet causal variants remain elusive. It is therefore important to define the full spectrum of genetic variants in the wider regions surrounding these significantly associated loci.
View Article and Find Full Text PDFFEBS J
December 2024
Laboratory of Germline Biology, Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.
Discovered two decades ago, PIWI-interacting RNAs (piRNAs) are crucial for silencing transposable elements (TEs) in animal gonads, thereby protecting the germline genome from harmful transposition, and ensuring species continuity. Silencing of TEs is achieved through transcriptional and post-transcriptional suppression by piRNAs and the PIWI clade of Argonaute proteins within non-membrane structured organelle. These structures are composed of proteins involved in piRNA processing, including PIWIs and other proteins by distinct functional motifs such as the Tudor domain, LOTUS, and intrinsic disordered regions (IDRs).
View Article and Find Full Text PDFNat Commun
December 2024
State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, PR China.
The INO80 chromatin remodeling complex plays a critical role in shaping the dynamic chromatin environment. The diverse functions of the evolutionarily conserved INO80 complex have been widely reported. However, the role of INO80 in modulating the histone variant H2A.
View Article and Find Full Text PDFNat Commun
December 2024
Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY, 11724, USA.
Modern maize (Zea mays ssp. mays) was domesticated from Teosinte parviglumis (Zea mays ssp. parviglumis), with subsequent introgressions from Teosinte mexicana (Zea mays ssp.
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