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Molecular crowding creates an essential environment for the formation of stable G-quadruplexes in long double-stranded DNA

Large numbers of guanine-rich sequences with potential to form G-quadruplexes have been identified in genomes of various organisms. Such sequences are constrained at both ends by long DNA duplex with a complementary strand in close proximity to compete for duplex formation. G-quadruplex/duplex compe...

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Detalles Bibliográficos
Autores principales: Zheng, Ke-wei, Chen, Zhao, Hao, Yu-hua, Tan, Zheng
Formato: Texto
Lenguaje:English
Publicado: Oxford University Press 2010
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2800236/
https://www.ncbi.nlm.nih.gov/pubmed/19858105
http://dx.doi.org/10.1093/nar/gkp898
Descripción
Sumario:Large numbers of guanine-rich sequences with potential to form G-quadruplexes have been identified in genomes of various organisms. Such sequences are constrained at both ends by long DNA duplex with a complementary strand in close proximity to compete for duplex formation. G-quadruplex/duplex competition in long double-stranded DNA has rarely been studied. In this work, we used DMS footprinting and gel electrophoresis to study G-quadruplex formation in long double-stranded DNA derived from human genome under both dilute and molecular crowding condition created by PEG. G-quadruplex formation was observed in the process of RNA transcription and after heat denaturation/renaturation under molecular crowding condition. Our results showed that the heat denaturation/renaturation treatment followed by gel electrophoresis could provide a simple method to quantitatively access the ability of G-quadruplex formation in long double-stranded DNA. The effect of K(+) and PEG concentration was investigated and we found that stable G-quadruplexes could only form under the crowding condition with PEG at concentrations near the physiological concentration of biomass in living cells. This observation reveals a physical basis for the formation of stable G-quadruplexes in genome and supports its presence under the in vivo molecular crowding condition.