@article {McKerrow2021.01.19.427347, author = {Wilson McKerrow and Nicole Doudican and Nicholas Frazzette and Shane A. Evans and Azucena Rocha and Larisa Kagermazova and John M. Sedivy and Nicola Neretti and John Carucci and Jef D. Boeke and David Feny{\"o}}, title = {LINE-1 Retrotransposon expression in cancerous, epithelial and neuronal cells revealed by 5{\textquoteright} single-cell RNA-Seq}, elocation-id = {2021.01.19.427347}, year = {2022}, doi = {10.1101/2021.01.19.427347}, publisher = {Cold Spring Harbor Laboratory}, abstract = {LINE-1 retrotransposons are sequences capable of copying themselves to new genomic loci via an RNA intermediate. New studies implicate LINE-1 in a range of diseases, especially in the context of aging, but without an accurate understanding of where and when LINE-1 is expressed, a full accounting of its role in health and disease is not possible. We therefore developed a method {\textendash} 5{\textquoteright} scL1seq {\textendash} that makes use of a widely available library preparation method (10x Genomics 5{\textquoteright} single cell RNA-seq) to measure LINE-1 expression in tens of thousands of single cells. We recapitulated the known pattern of LINE-1 expression in tumors {\textendash} present in cancer cells, absent from immune cells {\textendash} and identified hitherto undescribed LINE-1 expression in human epithelial cells and mouse hippocampal neurons. In both cases, we saw a modest increase with age, supporting recent research connecting LINE-1 to age related diseases.Competing Interest StatementDavid Feny{\"o} is a Founder and President of The Informatics Factory, and serves or served on the Scientific Advisory Board or consults for: Spectragen Informatics, Protein Metrics, Preverna. Jef Boeke is a Founder and Director of CDI Labs, Inc., a Founder of and consultant to Neochromosome, Inc, a Founder, SAB member of and consultant to ReOpen Diagnostics, LLC and serves or served on the Scientific Advisory Board of the following: Sangamo, Inc., Modern Meadow, Inc., Rome Therapeutics, Inc., Sample6, Inc., Tessera Therapeutics, Inc. and the Wyss Institute. John Sedivy is a cofounder of Transposon Therapeutics, Inc., serves as Chair of its Scientific Advisory Board, and consults for Astellas Innovation Management LLC, Atropos Therapeutics, Inc. and Gilead Sciences, Inc. John Carucci receives research funding from Regeneron, is a clinical investigator for Regeneron and Incyte, and prepared educational materials for Genentech.}, URL = {https://www.biorxiv.org/content/early/2022/01/04/2021.01.19.427347}, eprint = {https://www.biorxiv.org/content/early/2022/01/04/2021.01.19.427347.full.pdf}, journal = {bioRxiv} }