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.

• Klíčová slova
• DNA and RNA quadruplexes, G-quadruplexes, LTR retrotransposons, recombination, replication, transcription, transposable elements,
• 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
• Názvy látek
• DNA vazebné proteiny MeSH
• retroelementy MeSH
• RNA MeSH
• transpozibilní elementy DNA MeSH

Sex chromosomes are an ideal system to study processes connected with suppressed recombination. We found evidence of microsatellite expansion, on the relatively young Y chromosome of the dioecious plant sorrel (Rumex acetosa, XY1Y2 system), but no such expansion on the more ancient Y chromosomes of liverwort (Marchantia polymorpha) and human. The most expanding motifs were AC and AAC, which also showed periodicity of array length, indicating the importance of beginnings and ends of arrays. Our data indicate that abundance of microsatellites in genomes depends on the inherent expansion potential of specific motifs, which could be related to their stability and ability to adopt unusual DNA conformations. We also found that the abundance of microsatellites is higher in the neighborhood of transposable elements (TEs) suggesting that microsatellites are probably targets for TE insertions. This evidence suggests that microsatellite expansion is an early event shaping the Y chromosome where this process is not opposed by recombination, while accumulation of TEs and chromosome shrinkage predominate later.

• MeSH
• A-DNA genetika   MeSH
• chromozomy rostlin genetika   MeSH
• duplikace genu MeSH
• hybridizace in situ fluorescenční MeSH
• lidé MeSH
• lidský chromozom Y genetika   MeSH
• Marchantia genetika   MeSH
• metafáze genetika   MeSH
• mikrosatelitní repetice genetika   MeSH
• modely genetické MeSH
• molekulární evoluce * MeSH
• periodicita MeSH
• Rumex genetika   MeSH
• sekvence nukleotidů MeSH
• sekvenční analýza DNA MeSH
• transpozibilní elementy DNA genetika   MeSH
• Z-DNA genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• A-DNA MeSH
• transpozibilní elementy DNA MeSH
• Z-DNA MeSH

UV absorption and CD spectroscopy, along with polyacrylamide gel electrophoresis, were used to study conformational properties of DNA fragments containing the trinucleotide repeat (GCC)(n) (n = 4, 8 or 16), whose expansion is correlated with the fragile X chromosome syndrome. We have found that the conformational spectrum of the (GCC)(n) strand is wider than has been shown so far. (GCC)(n) strands adopt the hairpin described in the literature under a wide range of salt concentrations, but only at alkaline (>7.5) pH values. However, at neutral and slightly acid pH (GCC)(4) and (GCC)(8) strands homodimerize. Our data suggest that the homodimer is a bimolecular tetraplex formed by two parallel-oriented hairpins held together by hemi-protonated intermolecular C.C(+) pairs. The (GCC)(16) strand forms the same tetraplex intramolecularly. We further show that below pH 5 (GCC)(n) strands generate intercalated cytosine tetraplexes, whose molecularity depends on DNA strand length. They are tetramolecular with (GCC)(4), bimolecular with (GCC)(8) and monomolecular with (GCC)(16). i-Tetraplex formation is a complex and slow process. The neutral tetraplex, on the other hand, arises with fast kinetics under physiological conditions. Thus it is a conformational alternative of the (GCC)(n) strand duplex with a complementary (GGC)(n) strand.

• MeSH
• cirkulární dichroismus MeSH
• dimerizace MeSH
• DNA chemie   MeSH
• elektroforéza v polyakrylamidovém gelu MeSH
• konformace nukleové kyseliny * MeSH
• lidé MeSH
• spektrofotometrie ultrafialová MeSH
• syndrom fragilního X genetika   MeSH
• trinukleotidové repetice * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA MeSH