The nuclear periphery confers repression on H3K9me2-marked genes and transposons to shape cell fate - Nature Cell Biology
Marin et al. report the role of lamin proteins and the lamin B receptor (LBR) in chromatin positioning at the nuclear periphery. Knockout of all lamins and LBR in mouse embryonic stem cells leads to heterochromatin detachment and derepression of gene and transposon expression.
Plants repress ROS1 expression to attenuate heat-induced transposon burst - Nature Plants
Plants suppress the DNA demethylase ROS1 under heat stress to limit transposon activation, preventing genome instability. This conserved mechanism balances stress adaptation with genome protection.
A comprehensive atlas of full-length Arabidopsis eccDNA populations identifies their genomic origins and epigenetic regulation
Previous studies of extrachromosomal circular DNA (eccDNA) in plants are based on short-read sequencing and cannot efficiently identify their full-length, generated from transposable elements. This study uses long-read sequencing to obtain a comprehensive map of full-length eccDNAs from Arabidopsis and identifies their genomic origins and epigenetic regulation.
Long-read detection of transposable element mobilization in the soma of hypomethylated Arabidopsis thaliana individuals - Genome Biology
Background Because transposable elements (TEs) can cause heritable genetic changes, past work on TE mobility in Arabidopsis thaliana has mostly focused on new TE insertions in the germline of hypomethylated plants. It is, however, well-known that TEs can also be active in the soma, although the high-confidence detection of somatic events has been challenging. Results Here, we leverage the high accuracy of PacBio HiFi long reads to evaluate the somatic mobility of TEs in individuals of an A. thaliana non-reference strain lacking activity of METHYLTRANSFERASE1 (MET1), a major component of the DNA methylation maintenance machinery. Most somatically mobile families coincide with those found in germline studies of hypomethylated genotypes, although the exact TE copies differ. We also discover mobile elements that had been missed by standard TE annotation methods. Somatic TE activity is variable among individual plants, but also within TE families. Finally, our approach points to the possible involvement of alternative transposition as a cause for somatic hypermutability in a region that contains two closely spaced VANDAL21 elements. Conclusions Long-read sequencing reveals widespread TE transposition in the soma of A. thaliana hypomethylated mutants. Assessing somatic instead of germline mobilization is a fast and reliable method to investigate different aspects of TE mobility at the single plant level.
Effective population size does not explain long-term variation in genome size and transposable element content in animals.
#Transposons #TEs #PopulationSize #GenomeSize #NeutralTheory #GeneticDrift
https://elifesciences.org/articles/100574
Effective population size does not explain long-term variation in genome size and transposable element content in animals
A large-scale survey across animals reveals no general association between genome size expansion and the relaxation of natural selection.
Amelia Cervera 🧬