BACKGROUND: Transposable elements form a significant proportion of eukaryotic genomes. Recently, Lexa et al. (Nucleic Acids Res 42:968-978, 2014) reported that plant long terminal repeat (LTR) retrotransposons often contain potential quadruplex sequences (PQSs) in their LTRs and experimentally confirmed their ability to adopt four-stranded DNA conformations. RESULTS: Here, we searched for PQSs in human retrotransposons and found that PQSs are specifically localized in the 3'-UTR of LINE-1 elements, in LTRs of HERV elements and are strongly accumulated in specific regions of SVA elements. Circular dichroism spectroscopy confirmed that most PQSs had adopted monomolecular or bimolecular guanine quadruplex structures. Evolutionarily young SVA elements contained more PQSs than older elements and their propensity to form quadruplex DNA was higher. Full-length L1 elements contained more PQSs than truncated elements; the highest proportion of PQSs was found inside transpositionally active L1 elements (PA2 and HS families). CONCLUSIONS: Conservation of quadruplexes at specific positions of transposable elements implies their importance in their life cycle. The increasing quadruplex presence in evolutionarily young LINE-1 and SVA families makes these elements important contributors toward present genome-wide quadruplex distribution.

• MeSH
• dlouhé rozptýlené jaderné elementy MeSH
• elementy Alu MeSH
• endogenní retroviry MeSH
• G-kvadruplexy * MeSH
• genomika MeSH
• lidé MeSH
• mapování chromozomů MeSH
• repetitivní sekvence nukleových kyselin MeSH
• transpozibilní elementy DNA * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

A significant part of eukaryotic genomes is formed by transposable elements (TEs) containing not only genes but also regulatory sequences. Some of the regulatory sequences located within TEs can form secondary structures like hairpins or three-stranded (triplex DNA) and four-stranded (quadruplex DNA) conformations. This review focuses on recent evidence showing that G-quadruplex-forming sequences in particular are often present in specific parts of TEs in plants and humans. We discuss the potential role of these structures in the TE life cycle as well as the impact of G-quadruplexes on replication, transcription, translation, chromatin status, and recombination. The aim of this review is to emphasize that TEs may serve as vehicles for the genomic spread of G-quadruplexes. These non-canonical DNA structures and their conformational switches may constitute another regulatory system that, together with small and long non-coding RNA molecules and proteins, contribute to the complex cellular network resulting in the large diversity of eukaryotes.

• MeSH
• DNA vazebné proteiny metabolismus   MeSH
• G-kvadruplexy * MeSH
• genomika MeSH
• lidé MeSH
• otevřené čtecí rámce MeSH
• regulace genové exprese MeSH
• regulační oblasti nukleových kyselin MeSH
• repetitivní sekvence nukleových kyselin MeSH
• replikace DNA MeSH
• retroelementy genetika   MeSH
• RNA chemie   genetika   MeSH
• rostliny genetika   MeSH
• transpozibilní elementy DNA genetika   MeSH
• vazba proteinů MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH