Taken together, we propose a genetically encoded model in which L1 and B1/Alu repeats blueprint chromatin macrostructure. Our model explains the robustness of genome folding into a common conserved core, on which dynamic gene regulation is overlaid across cells.

Jan 29, 2021 · We find that homotypic clustering of L1 and B1/Alu demarcates the genome into grossly exclusive domains, and characterizes and predicts Hi-C compartments.

By applying bioinformatics to analyze the 5′ junctions of recent L1 insertions in the human genome, we provide evidence that L1 uses at least two distinct mechanisms to link the 5′-end of the nascent L1 copy to its genomic target.

A small minority of L1, Alu, and SVA (SINE–variable number of tandem repeats–Alu) elements retain functional promoters that enable them to be transcribed and to retrotranspose. Alu elements are currently the most active retrotransposon in the human germ line, manifesting an estimated insertion rate of 1 in 20 live births ( 82 ).

LINE-1 or L1 has driven the generation of at least 10% of the human genome by mobilising Alu sequences. Although there is no doubt that Alu insertion is initiated by L1-dependent target site-primed reverse transcription, the mechanism by which the ...

Apr 4, 2019 · Despite a pronounced cis preference for its own RNA, L1 is also responsible for the trans mobilization of non-autonomous retrotransposons, such as Alu or SVA sequences, and cellular mRNAs, following a similar mechanism (Kazazian and Moran, 2017).

Mar 12, 2025 · The poly(A) tail’s sequence composition impacts Alu RNA binding to L1-encoded proteins, which are required for reverse transcription and genomic reintegration. Variability in poly(A) tail length among different Alu copies affects their retrotranspositional activity.

Jun 1, 2023 · Homotypic clustering of long interspersed nuclear element 1 (LINE1 or L1) and B1/Alu retrotransposons forms grossly exclusive nuclear domains that characterize and predict heterochromatin and euchromatin, respectively.

Oct 23, 2018 · Therefore, based on their genomic distribution, L1 and Alu elements represent chromatin compartments with opposing features. Furthermore, L1 and, potentially, Alu activity represents a potential threat for the integrity and stability of the genome, in both dividing and nondividing cells.

Aug 9, 2012 · Our analysis reveals that in human cells marked Alu inserts driven by either exogenously supplied full length L1 or ORF2 protein are indistinguishable. Four percent of de novo Alu inserts were associated with genomic deletions and rearrangements and lacked the hallmarks of retrotransposition.