Retrotransposon#SINEs

In short interspersed nuclear elements ( SINE, engl. For, short interspersed nuclear elements sequence ') is understood to typically 100-400 base pairs in length, often repeated and relatively freely distributed DNA sequences in the genome. SINEs are often counted among the transposable elements that use an RNA intermediate ( retroelement ) and do not possess long terminal repeats ( LTR retrotransposons Non- ). Transposable elements in the strict sense, however, are defined as DNA sequences that encode a transposase itself and thus have an intrinsic ability to change their genomic position. In contrast to the longer LINEs SINEs are thus not autonomous but require an external reverse transcriptase ( often coded by LINEs ), since they do not own (more). Thus, they are retroposons (but not non- LTR retrotransposons about, which are themselves often missbenannt as retroposons ) in the strict sense.

SINEs vote in the 3 'sequence often with LINE sequences coincide and are often degenerate genes for small RNAs, such as 7SL RNA, or tRNAs. tRNA - related SINEs have a composite structure with a region homologous to a tRNA is a tRNA -like region, and not a variable ( 8-50 bp) AT-rich 3 'end. TRNA homologous sequence contains an RNA polymerase III promoter. They are therefore transcribed by RNA polymerase III.

A major SINE family is the so-called Alu family, which is found only in primates. Other families come in all mammals before (including monotremes and marsupials ) and are therefore also known as mammalian -wide interspersed repeats ( MIR ) refers. In some organisms, such as Drosophila or the nematode Caenorhabditis elegans lack SINEs.

SINEs do in the human genome of about 14%.