title: LINE retrotransposition and host DNA repair machinery.
abstract: Long interspersed elements (LINEs), or non-long-terminal repeat (LTR) retrotransposons, are mobile genetic elements that exist in the genomic DNA of most eukaryotes, comprising a considerable portion of the host chromosomes. LINEs constitute endogenous mutagens that cause insertional mutations in host chromosomes and have a large impact on host genome evolution. Despite their importance, however, the molecular mechanism of LINE retrotransposition is not fully understood. Several studies suggest that host proteins that participate in the repair of DNA breaks modulate LINE retrotransposition. Recently, we provided evidence that there are 2 distinct pathways-annealing and direct-that join the 5'-end of LINEs to host chromosomal DNA. These pathways appear to be used distinctively by zebrafish LINEs and the human L1 in DT40 cells. In HeLa cells, only the annealing pathway appears to be used. This implies that different characteristics of the 2 LINEs and also host factors dictate which pathway is selected. Here, we discuss the 5'-end-joining pathways of LINE retrotransposition and propose that the pathways of LINE integration adopt certain host repair factors.
authors.affiliation: Graduate School of Bioscience and Biotechnology; Tokyo Institute of Technology ; Yokohama, Kanagawa Japan.
authors.forename: Katsumi
authors.initials: K
authors.lastname: Yamaguchi
authors.affiliation: Graduate School of Bioscience and Biotechnology; Tokyo Institute of Technology ; Yokohama, Kanagawa Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Kajikawa
authors.affiliation: Graduate School of Bioscience and Biotechnology; Tokyo Institute of Technology; Yokohama, Kanagawa Japan; Department of Life Sciences; National Cheng Kung University; Tainan, Taiwan; Foundation for Advancement of International Science; Tsukuba, Japan.
authors.forename: Norihiro
authors.initials: N
authors.lastname: Okada
keywords: DNA double-strand breaks; Non-LTR retrotransposon; long interspersed element; microhomology-mediated end joining; non-homologous end joining; retrotransposition