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Updated: Jan 23, 2026

Repressing Gene Transcription by Redirecting Cellular Machinery with Chemical Epigenetic Modifiers
Published on: September 20, 2018
LINE-1 Evasion of Epigenetic Repression in Humans
Francisco J Sanchez-Luque1, Marie-Jeanne H C Kempen2, Patricia Gerdes3
1Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia; GENYO Centre for Genomics and Oncological Research, Pfizer University of Granada, Andalusian Regional Government, Avda Ilustración, 114, PTS Granada 18016, Spain.
Abstract:
Epigenetic silencing defends against LINE-1 (L1) retrotransposition in mammalian cells. However, the mechanisms that repress young L1 families and how L1 escapes to cause somatic genome mosaicism in the brain remain unclear. Here we report that a conserved Yin Yang 1 (YY1) transcription factor binding site mediates L1 promoter DNA methylation in pluripotent and differentiated cells. By analyzing 24 hippocampal neurons with three distinct single-cell genomic approaches, we characterized and validated a somatic L1 insertion bearing a 3' transduction. The source (donor) L1 for this insertion was slightly 5' truncated, lacked the YY1 binding site, and was highly mobile when tested in vitro. Locus-specific bisulfite sequencing revealed that the donor L1 and other young L1s with mutated YY1 binding sites were hypomethylated in embryonic stem cells, during neurodifferentiation, and in liver and brain tissue. These results explain how L1 can evade repression and retrotranspose in the human body.
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