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bioRxiv · 10.1101/2020.05.06.080622

Detect Genomic G-Quadruplexes in Living Animal Cells with a Tiny Artificial Protein Probe

Zheng, K.-w.·Zhang, J.-y.·He, Y.-d.·Gong, J.-y.·Wen, C.-j.·Chen, J.-n.·Hao, Y.-h.·Tan, Z.
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Abstract

G-quadruplex (G4) structures formed by guanine-rich nucleic acids are implicated in essential physiological processes and serve as important drug targets. The genome-wide detection of G4s in living cells is important for exploring the biological role of G4s but has not yet been achieved due to the lack of a suitable G4 probe. We engineered a 6.7 kDa G4 probe (G4P) protein that binds G4s with high affinity and specificity. We used it to capture G4s in living human, mouse, and chicken cells with the ChIP-Seq technology, yielding genome-wide landscape as well as details on the positions, frequencies, and sequence identities of G4 formation in these cells. Our results indicate that transcription is accompanied by a robust formation of G4s in genes. In human cells, we detected up to >123,000 G4 peaks, of which >1/3 had a fold increase of [≥]5 and were present in >60% promoters and ~70% genes. Being much smaller than a scFv antibody (27 kDa) or even a nanobody (12-15 kDa), we expect that the G4P may find diverse applications in biology, medicine, and molecular devices as a G4 affinity agent.

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Zheng, K.-w., Zhang, J.-y., He, Y.-d., Gong, J.-y., Wen, C.-j., Chen, J.-n., Hao, Y.-h., Tan, Z.. 2020-05-08. Detect Genomic G-Quadruplexes in Living Animal Cells with a Tiny Artificial Protein Probe. https://doi.org/10.1101/2020.05.06.080622

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