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Updated: Dec 22, 2025

Single-Molecule Fluorescence Visualization of DNA Polymerase Dynamics at G-Quadruplexes
Published on: April 4, 2025
DNA:RNA hybrid G-quadruplex formation upstream of transcription start site
Jia-Yu Zhang1,2, Ye Xia1, Yu-Hua Hao1
1State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences (CAS), Beijing, 100101, P. R. China.
Abstract:
Bioinformatic analysis reveals an enrichment of putative DNA:RNA hybrid G-quadruplex-forming sequences (PHQS) on both sides of the transcription start sites (TSSs) in the genome of warm-blooded animals, suggesting a positive selection of PHQSs in evolution and functional role of DNA:RNA hybrid G-quadruplexes (HQs) in transcription. The formation of HQs downstream of TSS in transcribed DNA has been documented under in vitro conditions; however, it is still not known if such HQs can form at the upstream side of TSSs. In this study, we report that such HQs can form in transcription in DNA with two to three guanine tracts if RNA carrying the required number of G-tracts is supplied. We also show that the formation of such HQs is dependent on the negative supercoiling generated by RNA polymerases. These results suggest that HQs may also form at the upstream side of TSSs in vivo and play a role in transcription since the two requirements are satisfied in cells.
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