A model for the mechanism of initial generation of short interspersed elements (SINEs).
Most animal genomes contain a large number of short interspersed elements (SINEs) that have a composite structure and contain a region that is homologous to a tRNA. The majority of SINEs have been found to be derived from a tRNA(Lys), being categorized as members of a superfamily of tRNA(Lys)-related SINEs. The consensus sequences of five SINEs that belong to this superfamily were aligned. It was found that, in the tRNA-unrelated region, there are two sequence motifs that are almost identical among these five SINEs and are at a distance of 10-11 nucleotides from each other. This observation suggests a common evolutionary origin of these SINEs and/or some function(s) for these motifs. Similar sequences were unexpectedly found to be present in the sequences complementary to the U5 regions of several mammalian retroviruses whose primer is a tRNA(Lys). On the basis of these findings, we propose a possible model for the generation of SINEs whereby they are derived from a "strong stop DNA" with a primer tRNA that is an intermediate in the process of reverse transcription of certain retroviruses.
Okada
N
N
Faculty of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, Japan.
Ohshima
K
K
D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D016384:Consensus Sequence; D017931:DNA Primers; D018076:DNA, Complementary / Q000235:genetics*; D004279:DNA, Viral / Q000235:genetics; D005814:Genes, Viral; D008957:Models, Genetic; D008969:Molecular Sequence Data; D011544:Pseudogenes; D012357:RNA, Transfer, Lys / Q000235:genetics*; D012190:Retroviridae / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid
D017931:DNA Primers; D018076:DNA, Complementary; D004279:DNA, Viral; D012357:RNA, Transfer, Lys