Human enteroviruses cause many diseases; however, there is no specific therapeutic drug. G-quadruplex is an atypical secondary structure formed in the guanine rich region of DNA or RNA, which can exist in the viral genome. The different positions of G-quadruplex play an important role in the regulation of virus replication and infection. Whether G-quadruplexes are present in human enteroviruses is unknown. In current study, we analyzed the potential quadruplex forming sequences of human enteroviruses, especially EV-A71 virus, which causes hand, foot, and mouth disease. The results showed that there were a certain number of potential quadruplex-forming sequences in human enteroviruses. Through a variety of experimental methods, we evaluated the formation potential of EV-A71 encoded G-quadruplex and analyzed the binding ability of G-quadruplex ligands, including BRACO-19, pyridostatin and TMPyP4 to virus encoded G-quadruplexes. G-quadruplex ligands BRACO-19, PDS and TMPyP4 could inhibit the transcription of constructs containing EV-A71 G-quadruplex sequences. Moreover, we found that BRACO-19 was able to inhibit the replication of EV-A71, suggesting that targeting G-quadruplexes in EV-A71 genome by G-quadruplex ligands could be a novel antiviral way against EV-A71. Our finding not only uncovered the G-quadruplexes in human enteroviruses, but also would provide a new strategy for human enteroviruses therapy.IMPORTANCE G-quadruplex is a stable nucleic acid secondary structure formed by the folding of guanine rich nucleic acid. The important regulatory function of G-quadruplex makes it an attractive target of antiviral effect. Human enteroviruses cause a variety of human diseases, including common cold, nervous system diseases, cardiovascular damage, and diabetes. Enterovirus A71 (EV-A71) is one of pathogens causing hand, foot, and mouth disease; however, whether G-quadruplexes are present in the genomes of human enteroviruses is unknown. The function of G-quadruplexes in the EV-A71 genomes is not clear. We predicted and characterized G-quadruplex sequences in EV-A71. G-quadruplex ligands were identified to stabilize EV-A71 G-quadruplexes with high affinities. We also demonstrated G-quadruplex ligand BRACO-19 inhibited EV-A71 replication. Our studies provide a framework for targeting G-quadruplexes in the enteroviruses genome, which will be a new way to develop antiviral agents against human enteroviruses.
Both human telomere and proto-oncogene c-MYC can form G-quadruplex (G4) with various conformations. Porphyrin derivative (TMPyP4) could stabilize G4, and thus is considered as a potential drug for anticancer therapeutics . In this paper, the translocation behaviors of three typical G4s (telomere basket, telomere hybrid-1 and c-MYC Pu22 parallel) and their interaction with TMPyP4 were investigated with a single protein nanopore sensing interface with the same main electrolyte of 0.5 M tetramethylammonium chloride. As observed by the statistics of the dwell time of the current pulses, in the presence of K + , the parallel G4 is more stable than the hybrid-1 G4, while the basket G4 in the presence of Na + exhibited shortest duration. The dwell time of all of the G4s increased as the result of interaction with TMPyP4, indicating an obvious stabilizing effect. This study demonstrated that the single nanopore sensing interface not only reveal the stability of various G4 conformations at a single-molecule level, but also provide the interaction information of a ligand, which could be useful in the drug design.
Lu Lv,Haoran Cui,Zhiyang Chen,Yixuan Zhou,Leiliang Zhang
Chikungunya virus (CHIKV) is a mosquito-transmitted alphavirus affecting human health globally. G-quadruplex secondary structures attract great attention as potential targets for antiviral strategy. In this study, we show that the CHIKV genome possesses several conserved potential G-quadruplex sequences. G-quadruplex ligands BRACO-19 and TMPyP4 could stabilize the CHIKV G-quadruplex and inhibit the transcription of constructs containing CHIKV G-quadruplex sequences. Importantly, BRACO-19 and TMPyP4 suppress CHIKV replication. Our study not only reinforces the presence of viral G-quadruplex sequences but also suggests that targeting G-quadruplex structure could represent a novel strategy to inhibit CHIKV. Highlights CHIKV possesses conserved G-quadruplexes G-quadruplex ligands stabilize CHIKV G-quadruplexes with high affinities G-quadruplex structures reduce the transcription of the GFP reporter gene containing CHIKV G-quadruplex G-quadruplex ligands BRACO-19 and TMPyP4 inhibit CHIKV replication
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