Regulation of mammalian LINE1 retrotransposon transcription

Comprehensive studies of higher eukaryote genomes and, especially, the results of successful projects on genome sequencing, have led us to the conclusion that not only unique DNA sequences, but also multiple families of repeats, have certain functions and are not just “junk” DNA. LINE1 retrotransposons are mobile elements that account for about one-fifth of mammalian genomes; they participate in the retrotransposition of cellular DNA, the organization of the chromatin structure, genome rearrangements, and the regulation of gene transcription. LINE1 elements are also involved in recombination and repair processes. In this review, the structural organization of LINE1 retrotransposons and the function and regulation of their tissue-specific transcription are discussed.