Gamma radiation increases endonuclease-dependent L1 retrotransposition in a cultured cell assay

Long Interspersed Elements (LINE-1s, L1s) are the most active mobile elements in the human genome and account for a significant fraction of its mass. The propagation of L1 in the human genome requires disruption and repair of DNA at the site of integration. As Barbara McClintock first hypothesized,...

Full description

Bibliographic Details
Main Authors:	Farkash, Evan A., Kao, Gary D., Horman, Shane R., Prak, Eline T. Luning
Format:	Online
Language:	English
Published:	Oxford University Press 2006
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1385994/

id	pubmed-1385994
recordtype	oai_dc
spelling	pubmed-13859942006-03-03 Gamma radiation increases endonuclease-dependent L1 retrotransposition in a cultured cell assay Farkash, Evan A. Kao, Gary D. Horman, Shane R. Prak, Eline T. Luning Article Long Interspersed Elements (LINE-1s, L1s) are the most active mobile elements in the human genome and account for a significant fraction of its mass. The propagation of L1 in the human genome requires disruption and repair of DNA at the site of integration. As Barbara McClintock first hypothesized, genotoxic stress may contribute to the mobilization of transposable elements, and conversely, element mobility may contribute to genotoxic stress. We tested the ability of genotoxic agents to increase L1 retrotransposition in a cultured cell assay. We observed that cells exposed to gamma radiation exhibited increased levels of L1 retrotransposition. The L1 retrotransposition frequency was proportional to the number of phosphorylated H2AX foci, an indicator of genotoxic stress. To explore the role of the L1 endonuclease in this context, endonuclease-deficient tagged L1 constructs were produced and tested for their activity in irradiated cells. The activity of the endonuclease-deficient L1 was very low in irradiated cells, suggesting that most L1 insertions in irradiated cells still use the L1 endonuclease. Consistent with this interpretation, DNA sequences that flank L1 insertions in irradiated cells harbored target site duplications. These results suggest that increased L1 retrotransposition in irradiated cells is endonuclease dependent. The mobilization of L1 in irradiated cells potentially contributes to genomic instability and could be a driving force for secondary mutations in patients undergoing radiation therapy. Oxford University Press 2006 2006-02-28 /pmc/articles/PMC1385994/ /pubmed/16507671 http://dx.doi.org/10.1093/nar/gkj522 Text en © The Author 2006. Published by Oxford University Press. All rights reserved
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Farkash, Evan A. Kao, Gary D. Horman, Shane R. Prak, Eline T. Luning
spellingShingle	Farkash, Evan A. Kao, Gary D. Horman, Shane R. Prak, Eline T. Luning Gamma radiation increases endonuclease-dependent L1 retrotransposition in a cultured cell assay
author_facet	Farkash, Evan A. Kao, Gary D. Horman, Shane R. Prak, Eline T. Luning
author_sort	Farkash, Evan A.
title	Gamma radiation increases endonuclease-dependent L1 retrotransposition in a cultured cell assay
title_short	Gamma radiation increases endonuclease-dependent L1 retrotransposition in a cultured cell assay
title_full	Gamma radiation increases endonuclease-dependent L1 retrotransposition in a cultured cell assay
title_fullStr	Gamma radiation increases endonuclease-dependent L1 retrotransposition in a cultured cell assay
title_full_unstemmed	Gamma radiation increases endonuclease-dependent L1 retrotransposition in a cultured cell assay
title_sort	gamma radiation increases endonuclease-dependent l1 retrotransposition in a cultured cell assay
description	Long Interspersed Elements (LINE-1s, L1s) are the most active mobile elements in the human genome and account for a significant fraction of its mass. The propagation of L1 in the human genome requires disruption and repair of DNA at the site of integration. As Barbara McClintock first hypothesized, genotoxic stress may contribute to the mobilization of transposable elements, and conversely, element mobility may contribute to genotoxic stress. We tested the ability of genotoxic agents to increase L1 retrotransposition in a cultured cell assay. We observed that cells exposed to gamma radiation exhibited increased levels of L1 retrotransposition. The L1 retrotransposition frequency was proportional to the number of phosphorylated H2AX foci, an indicator of genotoxic stress. To explore the role of the L1 endonuclease in this context, endonuclease-deficient tagged L1 constructs were produced and tested for their activity in irradiated cells. The activity of the endonuclease-deficient L1 was very low in irradiated cells, suggesting that most L1 insertions in irradiated cells still use the L1 endonuclease. Consistent with this interpretation, DNA sequences that flank L1 insertions in irradiated cells harbored target site duplications. These results suggest that increased L1 retrotransposition in irradiated cells is endonuclease dependent. The mobilization of L1 in irradiated cells potentially contributes to genomic instability and could be a driving force for secondary mutations in patients undergoing radiation therapy.
publisher	Oxford University Press
publishDate	2006
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1385994/
_version_	1611380910316322816

Gamma radiation increases endonuclease-dependent L1 retrotransposition in a cultured cell assay

Similar Items