LINE-1 retrotransposons: modulators of quantity and quality of mammalian gene expression?
LINE-1 (L1) retrotransposons are replicating repetitive elements that, by mass, are the most-abundant sequences in the human genome. Over one-third of mammalian genomes are the result, directly or indirectly, of L1 retrotransposition. L1 encodes two proteins: ORF1, an RNA-binding protein, and ORF2, an endonuclease/reverse transcriptase. Both proteins are required for L1 mobilization. Apart from the obvious function of self-replication, it is not clear what other roles, if any, L1 plays within its host. The sheer magnitude of L1 sequences in our genome has fueled speculation that over evolutionary time L1 insertions may structurally modify endogenous genes and regulate gene expression. Here we provide a review of L1 replication and its potential functional consequences.
Han
Jeffrey S
JS
Department of Molecular Biology and Genetics and High Throughput Biology Center, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
Boeke
Jef D
JD
D000483:Alleles; D003593:Cytoplasm / Q000378:metabolism; D004247:DNA / Q000737:chemistry; D004251:DNA Transposable Elements / Q000235:genetics*; D044127:Epigenesis, Genetic; D019143:Evolution, Molecular; D005091:Exons; D005786:Gene Expression Regulation; D016678:Genome; D006801:Humans; D020084:Long Interspersed Nucleotide Elements; D008954:Models, Biological; D008957:Models, Genetic; D016366:Open Reading Frames; D012333:RNA, Messenger / Q000378:metabolism; D011995:Recombination, Genetic; D018626:Retroelements / Q000235:genetics*; D014466:Ultraviolet Rays
D004251:DNA Transposable Elements; D012333:RNA, Messenger; D018626:Retroelements; D004247:DNA