20250423_Scripts.docx

Retroelements (REs) constitute approximately 40% of the mammalian genome and can cause large-scale genomic changes. Although the roles of REs in aging have been studied, the specific types of REs transcribed during aging, their tissue-specific activation, and their potential insertion into other genomic loci remain unclear. This project examines whether specific RE RNA is upregulated in the liver during aging and inserted into other loci. Long-read genome sequencing analysis revealed new cell-specific RE insertions in the cells of the liver throughout the lifespan of both young and old mice. Although some insertions differ between individuals in the genome were identified, we did not find any difference in the number of insertions between ages. Meanwhile, transcripts from a specific RE (Chr2_RE) were upregulated in the liver of old mice, and chimeric reads between the Chr2_RE region and other loci were detected only in old mice through short-read genome sequencing, suggesting age-dependent insertion of Chr2_RE into other loci. This study provides new insights into the role of REs in aging.