Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2018 Feb 5;8(1):2366.
doi: 10.1038/s41598-018-20852-w.

Characterizations of distinct parallel and antiparallel G-quadruplexes formed by two-repeat ALS and FTD related GGGGCC sequence

Bo Zhou  1   2 , Yanyan Geng  3 , Changdong Liu  3 , Haitao Miao  3 , Yaguang Ren  3 , Naining Xu  3 , Xiao Shi  3 , Yingying You  3 , Tunglun Lee  3 , Guang Zhu  4
Affiliations

Characterizations of distinct parallel and antiparallel G-quadruplexes formed by two-repeat ALS and FTD related GGGGCC sequence

Bo Zhou et al. Sci Rep. .

Abstract

The large expansion of GGGGCC (G4C2) repeats of the C9orf72 gene have been found to lead to the pathogenesis of devastating neurological diseases, amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The structural polymorphisms of C9orf72 HRE DNA and RNA may cause aberrant transcription and contribute to the development of ALS and FTD. Here we showed that the two-repeat G4C2 DNA, d(G4C2)2, simultaneously formed parallel and antiparallel G-quadruplex conformations in the potassium solution. We separated different folds of d(G4C2)2 by anion exchange chromatography, followed with characterizations by circular dichroism and nuclear magnetic resonance spectroscopy. The parallel d(G4C2)2 G-quadruplex folded as a symmetric tetramer, while the antiparallel d(G4C2)2 adopted the topology of an asymmetric dimer. These folds are distinct from the antiparallel chair-type conformation we previously identified for the d(G4C2)4 G-quadruplex. Our findings have demonstrated the conformational heterogeneity of the C9orf72 HRE DNA, and provided new insights into the d(G4C2)n folding. Meanwhile, the purified d(G4C2)2 G-quadruplex samples are suitable for further three-dimensional structure characterizations, which are required for the structure-based design of small molecules targeting ALS and FTD related C9orf72 HRE.

PubMed Disclaimer

Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Figure 1
Figure 1
Anion exchange chromatography purification of d(G4C2)2. (a) The imino region of 1D 1H spectrum of d(G4C2)2. (b) Gel electrophoresis of d(G4C2)2 and anion exchange chromatography fractions monitored by the staining method. (c) Elution profile of d(G4C2)2 from Mono-Q column.
Figure 2
Figure 2
CD spectra of anion exchange chromatography fractions of d(G4C2)2. The concentration of each fraction was 20 μM.
Figure 3
Figure 3
CD melting curves of anion exchange chromatography fractions of d(G4C2)2. The melting experiments were performed with a temperature range of 25 °C to 95 °C at 1 °C/min. The CD absorbance was measured at a single wavelength (290 nm for F1, F2 and F3, and 260 nm for F4, F5 and F6). Data were fit by the Boltzmann sigmoid equation (Prism).
Figure 4
Figure 4
1D 1H spectra showed the imino region of d(G4C2)2 and anion exchange chromatography fractions. The spectra were recorded in 90% H2O, 10% D2O at 25 °C.
See this image and copyright information in PMC

References

    1. Rowland LP, Shneider NA. Amyotrophic lateral sclerosis. N. Engl. J. Med. 2001;344:1688–1700. doi: 10.1056/NEJM200105313442207. - DOI - PubMed
    1. Kiernan MC, et al. Amyotrophic lateral sclerosis. Lancet. 2011;377:942–955. doi: 10.1016/S0140-6736(10)61156-7. - DOI - PubMed
    1. Rademakers R, Neumann M, Mackenzie IR. Advances in understanding the molecular basis of frontotemporal dementia. Nat. Rev. Neurol. 2012;8:423–434. doi: 10.1038/nrneurol.2012.117. - DOI - PMC - PubMed
    1. DeJesus-Hernandez M, et al. Expanded GGGGCC hexanucleotide repeat in noncoding region of C9ORF72 causes chromosome 9p-linked FTD and ALS. Neuron. 2011;72:245–256. doi: 10.1016/j.neuron.2011.09.011. - DOI - PMC - PubMed
    1. Renton AE, et al. A hexanucleotide repeat expansion in C9ORF72 is the cause of chromosome 9p21-linked ALS-FTD. Neuron. 2011;72:257–268. doi: 10.1016/j.neuron.2011.09.010. - DOI - PMC - PubMed

Publication types

LinkOut - more resources