RT Journal Article T1 Engineered LINE-1 retrotransposition in nondividing human neurons. A1 Macia, Angela A1 Widmann, Thomas J A1 Heras, Sara R A1 Ayllon, Veronica A1 Sanchez, Laura A1 Benkaddour-Boumzaouad, Meriem A1 Muñoz-Lopez, Martin A1 Rubio, Alejandro A1 Amador-Cubero, Suyapa A1 Blanco-Jimenez, Eva A1 Garcia-Castro, Javier A1 Menendez, Pablo A1 Ng, Philip A1 Muotri, Alysson R A1 Goodier, John L A1 Garcia-Perez, Jose L AB Half the human genome is made of transposable elements (TEs), whose ongoing activity continues to impact our genome. LINE-1 (or L1) is an autonomous non-LTR retrotransposon in the human genome, comprising 17% of its genomic mass and containing an average of 80-100 active L1s per average genome that provide a source of inter-individual variation. New LINE-1 insertions are thought to accumulate mostly during human embryogenesis. Surprisingly, the activity of L1s can further impact the somatic human brain genome. However, it is currently unknown whether L1 can retrotranspose in other somatic healthy tissues or if L1 mobilization is restricted to neuronal precursor cells (NPCs) in the human brain. Here, we took advantage of an engineered L1 retrotransposition assay to analyze L1 mobilization rates in human mesenchymal (MSCs) and hematopoietic (HSCs) somatic stem cells. Notably, we have observed that L1 expression and engineered retrotransposition is much lower in both MSCs and HSCs when compared to NPCs. Remarkably, we have further demonstrated for the first time that engineered L1s can retrotranspose efficiently in mature nondividing neuronal cells. Thus, these findings suggest that the degree of somatic mosaicism and the impact of L1 retrotransposition in the human brain is likely much higher than previously thought. YR 2016 FD 2016-12-13 LK http://hdl.handle.net/10668/10676 UL http://hdl.handle.net/10668/10676 LA en DS RISalud RD Apr 6, 2025