scholarly journals The parallel G-quadruplex structure of vertebrate telomeric repeat sequences is not the preferred folding topology under physiological conditions

2011 ◽  
Vol 39 (13) ◽  
pp. 5768-5775 ◽  
Author(s):  
Robert Hänsel ◽  
Frank Löhr ◽  
Silvie Foldynová-Trantírková ◽  
Ernst Bamberg ◽  
Lukáš Trantírek ◽  
...  
Keyword(s):  
Telomeric Repeat ◽  
Physiological Conditions ◽  
Quadruplex Structure ◽  
Repeat Sequences ◽  
G Quadruplex

scholarly journals A novel G-quadruplex motif in the Human MET promoter region

2017 ◽  
Vol 37 (6) ◽  
Author(s):  
Jing Yan ◽  
Deming Zhao ◽  
Liping Dong ◽  
Shuang Pan ◽  
Fengjin Hao ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gene Expression Regulation ◽  
Luciferase Assay ◽  
Klenow Fragment ◽  
Regulate Gene Expression ◽  
Physiological Conditions ◽  
Quadruplex Structure ◽  
G Quadruplex ◽  
Quadruplex Formation

It is known that the guanine-rich strands in proto-oncogene promoters can fold into G-quadruplex structures to regulate gene expression. An intramolecular parallel G-quadruplex has been identified in MET promoter. It acts as a repressor in regulating MET expression. However, the full guanine-rich region in MET promoter forms a hybrid parallel/antiparallel G-quadruplex structure under physiological conditions, which means there are some antiparallel and hybrid parallel/antiparallel G-quadruplex structures in this region. In the present study, our data indicate that g3-5 truncation adopts an intramolecular hybrid parallel/antiparallel G-quadruplex under physiological conditions in vitro. The g3-5 G-quadruplex structure significantly stops polymerization by Klenow fragment in K+ buffer. Furthermore, the results of circular dichroism (CD) spectra and polymerase stop assay directly demonstrate that the G-quadruplex structure in g3-5 fragment can be stabilized by the G-quadruplex ligand TMPyP4 (5,10,15,20-tetra-(N-methyl-4-pyridyl) porphine). But the dual luciferase assay indicates TMPyP4 has no effect on the formation of g3-5 G-quadruplex in HepG2 cells. The findings in the present study will enrich our understanding of the G-quadruplex formation in proto-oncogene promoters and the mechanisms of gene expression regulation.

Design and Synthesis of an Expanded Porphyrin That Has Selectivity for the c-MYC G-Quadruplex Structure

2005 ◽  
Vol 127 (9) ◽  
pp. 2944-2959 ◽  
Author(s):  
Jeyaprakashnarayanan Seenisamy ◽  
Sridevi Bashyam ◽  
Vijay Gokhale ◽  
Hariprasad Vankayalapati ◽  
Daekyu Sun ◽  
...  
Keyword(s):  
Design And Synthesis ◽  
Quadruplex Structure ◽  
G Quadruplex ◽  
Expanded Porphyrin

Inhibition of Protein Synthesis Through RNA-Based Tandem G-Quadruplex Formation

2021 ◽  
Author(s):  
Masaki Hagihara
Keyword(s):  
Protein Synthesis ◽  
Reverse Transcriptase ◽  
Repeat Sequences ◽  
Guanine Quadruplex ◽  
G Quadruplex ◽  
Inhibition Of Protein Synthesis ◽  
Quadruplex Formation

Tandem guanine repeat sequences can adopt guanine quadruplex (G-quadruplex) structures and consecutive guanine repeat sequences can potentially afford multiple G-quadruplex structures. By using a reverse transcriptase stop assay and biophysical...

scholarly journals Structure and Stability of a Dimeric G-Quadruplex Formed by Cyclic Oligonucleotides

2010 ◽  
Vol 2010 ◽  
pp. 1-6 ◽  
Author(s):  
Joan Casals ◽  
Júlia Viladoms ◽  
Enrique Pedroso ◽  
Carlos González
Keyword(s):  
Telomeric Repeat ◽  
High Melting ◽  
Structure And Stability ◽  
Dimeric Structure ◽  
Nmr Data ◽  
High Melting Temperature ◽  
Sodium Nmr ◽  
G Quadruplex ◽  
Global Topology ◽  
Quadruplex Formation

We have studied the structure and stability of the cyclic dodecamer d<pGGGTTAGGGTTA>, containing two copies of the human telomeric repeat. In the presence of sodium, NMR data are consistent with a dimeric structure of the molecule in which two cycles self-associate forming a quadruplex with three guanine tetrads connected by edgewise loops. The two macrocycles are arranged in a parallel way, and the dimeric structure exhibits a high melting temperature. These results indicate that cyclization of the phosphodiester chain does not prevent quadruplex formation, although it affects the global topology of the quadruplex.

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