title: Environmental influence on L1 retrotransposons in the adult hippocampus.
abstract: It is well established that neuronal circuits can be shaped by experience. Neuronal plasticity can be achieved by synaptic competitive interactions and the addition of new neuronal units in neurogenic regions of the adult brain. Recent data have suggested that neuronal progenitor cells can accommodate somatic LINE-1 (Long Interspersed Nuclear Elements-1 or L1) retrotransposition. Genomic L1 insertions may up- or down-regulate transcriptional control of gene expression. Here, we show that exercise has a positive effect on a L1-EGFP reporter in vivo. We found that neurons from mice that experience voluntary exercise are more likely to activate an EGFP reporter marker, representing L1 insertions in the brain, when compared with sedentary animals. In the hippocampus, a neurogenic region of the adult brain, EGFP expression is mainly found in cells localized in the subgranular layer of the dentate gyrus. This observation implies that neuronal progenitor cells may support de novo retrotransposition upon exposure to a new environment. Such evidence suggests that experience-dependent L1 retrotransposition may contribute to the physiological consequences of neuronal plasticity.
authors.affiliation: Department of Pediatrics/Cellular & Molecular Medicine, School of Medicine, UCSD Stem Cell Initiative, University of California, San Diego, 9500 Gilman Drive 0695, California, USA. muotri@ucsd.edu
authors.forename: Alysson R
authors.initials: AR
authors.lastname: Muotri
authors.forename: Chunmei
authors.initials: C
authors.lastname: Zhao
authors.forename: Maria C N
authors.initials: MC
authors.lastname: Marchetto
authors.forename: Fred H
authors.initials: FH
authors.lastname: Gage
mesh_terms: D053687:Adult Stem Cells / Q000502:physiology; D000818:Animals; D002470:Cell Survival / Q000502:physiology; D004777:Environment; D005455:Fluorescent Antibody Technique; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006624:Hippocampus / Q000502:physiology*; D020084:Long Interspersed Nucleotide Elements / Q000502:physiology*; D051379:Mice; D008822:Mice, Transgenic; D055495:Neurogenesis / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D010805:Physical Conditioning, Animal / Q000502:physiology*; D012420:Running / Q000502:physiology; D055153:Stem Cell Niche / Q000502:physiology; D014836:Volition
chemical_list: C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins