02229nas a2200193   4500008004100000022001400041245011400055210006900169260007100238300001400309490000700323520147700330100001801807700001601825700001901841700003101860700001801891856012601909       2014                        eng d  a0006-296000aIn the sense of transcription regulation by G-quadruplexes: asymmetric effects in sense and antisense strands0 aIn the sense of transcription regulation by Gquadruplexes asymme  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcJUN  a3711-37180 v533 a<p>G-Quadruplexes occupy important regulatory regions in the genome. DNA G-quadruplexes in the promoter regions and RNA quadruplexes in the UTRs (untranslated regions) have been individually studied and variously implicated at different regulatory levels of gene expression. However, the formation of G-quadruplexes in the sense and antisense strands and their corresponding roles in gene regulation have not been studied in much detail. In the present study, we have elucidated the effect of strand asymmetry in this context. Using biophysical methods, we have demonstrated the formation of stable G-quadruplex structure in vitro using CD and UV melting. Additionally, ITC was employed to demonstrate that a previously reported selective G-quadruplex ligand was able to bind and stabilize the G-quadruplex in the present sequence. Further, we have shown using reporter constructs that although the DNA G-quadruplex in either strand can reduce translation efficiency, transcriptional regulation differs when G-quadruplex is present in the sense or antisense strand. We demonstrate that the G-quadruplex motif in the antisense strand substantially inhibits transcription, while when in the sense strand, it does not affect transcription, although it does ultimately reduce translation. Further, it is also shown that the G-quadruplex stabilizing ligand can enhance this asymmetric transcription regulation as a result of the increased stabilization of the G-quadruplex.</p>1 aAgarwal, Tani1 aRoy, Saumya1 aKumar, Santosh1 aChakraborty, Tushar, Kanti1 aMaiti, Souvik  uhttps://library.ncl.res.in/content/sense-transcription-regulation-g-quadruplexes-asymmetric-effects-sense-and-antisense-002196nas a2200217   4500008004100000022001400041245009200055210006900147260007100216300001400287490000700301520139700308100001801705700002701723700001901750700001601769700003101785700002301816700001801839856012101857       2014                        eng d  a0006-296000aMorphological effects of G-quadruplex stabilization using a small molecule in zebrafish0 aMorphological effects of Gquadruplex stabilization using a small  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcFEB  a1117-11240 v533 a<p>Zebrafish (Danio rerio) embryos are transparent and advantageous for studying early developmental changes due to ex utero development, making them an appropriate model for studying gene expression changes as a result of molecular targeting. Zebrafish embryos were injected with a previously reported G-quadruplex selective ligand, and the phenotypic changes were recorded. We report marked discrepancies in the development of intersegmental vessels. In silico analysis determined that the putative G-quadruplex motif occur in the upstream promoter region of the Cdh5 (N-cadherin) gene. A real-time polymerase chain reaction-based investigation indicated that in zebrafish, CDH-2 (ZN-cad) was significantly downregulated in the ligand-treated embryos. Biophysical characterization of the interaction of the ligand with the G-quadruplex motif found in this promoter yielded strong binding and stabilization of the G-quadruplex with this ligand. Hence, we report for the first time the phenotypic impact of G-quadruplex targeting with a ligand in a vertebrate organism. This study has unveiled not only G-quadruplex targeting in non-human animal species but also the potential that G-quadruplexes can provide a ready tool for understanding the phenotypic effects of targeting certain important genes involved in differentiation and developmental processes in a living eukaryotic organism.</p>1 aAgarwal, Tani1 aLalwani, Mukesh, Kumar1 aKumar, Santosh1 aRoy, Saumya1 aChakraborty, Tushar, Kanti1 aSivasubbu, Sridhar1 aMaiti, Souvik  uhttps://library.ncl.res.in/content/morphological-effects-g-quadruplex-stabilization-using-small-molecule-zebrafish-0