Environments surrounding G-rich sequences remarkably affect the conformations of these structures. A proper evaluation system mimicking the crowded environment in a cell with macromolecules should be developed to perform structural and functional studies on G-quadruplexes. In this study, the topology and stability of a G-quadruplex formed by human telomeric repeat sequences were investigated in a macromolecule-crowded environment created by polyethylene glycol 200 (PEG200), tumor cell extract, and egg extract. The interactions between small molecules and telomeric G-quadruplexes were also evaluated in the different systems. The results suggested that the actual behavior of G-quadruplex structures in cells extract is quite different from that in the PEG crowding system, and proteins or other factors in extracts might play a very important role in G-quadruplex structures.
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http://dx.doi.org/10.1016/j.bbrep.2015.09.022 | DOI Listing |
Proc Natl Acad Sci U S A
January 2025
Max Perutz Labs, Vienna Biocenter Campus, Vienna 1030, Austria.
RNA G-quadruplexes (rG4s), the four-stranded structures formed by guanine-rich RNA sequences, are recognized by regions in RNA-binding proteins (RBPs) that are enriched in arginine-glycine repeats (RGG motifs). Importantly, arginine and glycine are encoded by guanine-rich codons, suggesting that some RGG motifs may both be encoded by and interact with rG4s in autogenous messenger RNAs (mRNAs). By analyzing transcriptome-wide rG4 datasets, we show that hundreds of RGG motifs in humans are at least partly encoded by rG4s, with an increased incidence for longer RGG motifs (~10 or more residues).
View Article and Find Full Text PDFChembiochem
January 2025
Bose Institute - Centenary Campus, Biophysics, P-1/12 CIT Scheme VIIM, Kankurgachi, Centenary Campus, 700054, KOLKATA, INDIA.
The Rous sarcoma virus (RSV) is an onco-retrovirus that infects avian species such as the chicken (Gallus gallus). RSV is the first oncovirus to be described, and the oncogenic activity of this virus is related to the expression of a tyrosine kinase that induces carcinogenic transformation. Interestingly, we have noted that the RSV genome contains various potential G4-forming sequences.
View Article and Find Full Text PDFRev Physiol Biochem Pharmacol
January 2025
Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland, UK.
Nucleic acids are highly charged, and electrical forces are involved heavily in how our DNA is compacted and packaged into such a small space, how chromosomes are formed, and how DNA damage is repaired. In addition, electrical forces are crucial to the formation of non-canonical DNA structures called G-Quadruplexes which play multiple biological roles.
View Article and Find Full Text PDFChembiochem
January 2025
Peking University, College of Chemistry and Molecular Engineering, No. 292 Chengfu Road, Haidian District, 100871, Beijing, CHINA.
Since the building blocks of DNA are nonfluorescent, various external fluorescence reporters have been employed to investigate the structure, dynamics, and function of DNA G-quadruplexes (GQs) and i-motifs (iMs), which play an important role in gene regulation and expression. However, most of those fluorescence reporters lack the ability to provide site-specific structural information of interest. Therefore, it is necessary to develop fluorescent nucleoside analogues that can be covalently inserted into oligonucleotides, which not only serve this purpose, but minimize any potential perturbation towards the native structure of the DNA systems in question.
View Article and Find Full Text PDFBiol Lett
January 2025
Discovery, InsideOutBio , Charlestown, MA, USA.
This paper is focused on the origins of the contemporary genetic code. A novel explanation is proposed for how the mapping of nucleotides in DNA to amino acids in proteins arose that derives from repeat nucleotide sequences able to form alternative nucleic acid structures (ANS), such as the unusual left-handed Z-DNA, triplex, G-quadruplex and I-motif conformations. The scheme identifies sequence-specific contacts that map ANS repeats to dipeptide polymers (DPS).
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