Links Between Repeated Sequences

[摘要] L1 andAluelements are long and short interspersedretrotransposable elements (LINEs and SINEs) in humans,respectively. Proteins encoded in the autonomous L1 mediateretrotransposition of the nonautonomousAluand cellularmRNAs.Aluis the only active SINE in the human genomeand is derived from 7SL RNA of signal recognition particle. In theother eukaryotic genomes, various tRNA- and 5S rRNA-derived SINEsare found. Some of the tRNA- and 5S rRNA-derived SINEs havepartner LINEs of which 3' sequences are similar to those of theSINEs. One of the tRNA-derived SINEs is shown to be mobilized byits partner LINE. Many copies of tRNA and 5S rRNA pseudogenes arepresent in the human genome. These pseudogenes may have beengenerated via the retrotransposition process using L1 proteins.Although there are no sequence similarities between L1 andAlu, L1 functionally links withAluand evencellular genes, impacting on our genome shaping.

[学科分类] 基础医学