LINE-1 ribonucleoprotein condensates bind DNA to enable nuclear entry during mitosis.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 40315332.
- Also identified by DOI 10.1126/sciadv.adt9318 and PMC identifier 12047440.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Long interspersed nuclear element-1 (LINE-1) is an autonomous retrotransposon that makes up a substantial portion of the human genome, contributing to genetic diversity and genome evolution. LINE-1 encodes two proteins, ORF1p and ORF2p, both essential for successful retrotransposition. ORF2p has endonuclease and reverse transcription activity, while ORF1p binds RNA. Many copies of ORF1p assemble onto the LINE-1 RNA to form a ribonucleoprotein (RNP) condensate. However, the function of these condensates in the LINE-1 life cycle remains unclear. Using reconstitution assays on DNA curtains, we show that L1 RNP condensates gain DNA binding activity only when RNA is super-saturated with ORF1p. In cells, L1 RNP condensates bind to chromosomes during mitosis. Mutational analysis reveals that DNA binding is crucial for nuclear entry and LINE-1 retrotransposition activity. Thus, a key function of ORF1p is to form an RNP condensate that gains access to the genome through DNA binding upon nuclear envelope breakdown.
Medical subject headings
- Long Interspersed Nucleotide Elements
- Mitosis
- Ribonucleoproteins
- DNA
- Cell Nucleus