» Articles » PMID: 39441636

Dominant and Genome-wide Formation of DNA:RNA Hybrid G-quadruplexes in Living Yeast Cells

Overview
Specialty Science
Date 2024 Oct 23
PMID 39441636
Authors
Affiliations
Soon will be listed here.
Abstract

Guanine-rich DNA forms G-quadruplexes (G4s) that play a critical role in essential cellular processes. Previous studies have mostly focused on intramolecular G4s composed of four consecutive guanine tracts (G-tracts) from a single strand. However, this structural form has not been strictly confirmed in the genome of living eukaryotic cells. Here, we report the formation of hybrid G4s (hG4s), consisting of G-tracts from both DNA and RNA, in the genome of living yeast cells. Analysis of Okazaki fragment syntheses and two other independent G4-specific detections reveal that hG4s can efficiently form with as few as a single DNA guanine-guanine (GG) tract due to the participation of G-tracts from RNA. This finding increases the number of potential G4-forming sites in the yeast genome from 38 to 587,694, a more than 15,000-fold increase. Interestingly, hG4s readily form and even dominate at G4 sites that are theoretically capable of forming the intramolecular DNA G4s (dG4s) by themselves. Compared to dG4s, hG4s exhibit broader kinetics, higher prevalence, and greater structural diversity and stability. Most importantly, hG4 formation is tightly coupled to transcription through the involvement of RNA, allowing it to function in a transcription-dependent manner. Overall, our study establishes hG4s as the overwhelmingly dominant G4 species in the yeast genome and emphasizes a renewal of the current perception of the structural form, formation mechanism, prevalence, and functional role of G4s in eukaryotic genomes. It also establishes a sensitive and currently the only method for detecting the structural form of G4s in living cells.

References
1.
Yeung R, Smith D . Determinants of Replication-Fork Pausing at tRNA Genes in . Genetics. 2020; 214(4):825-838. PMC: 7153945. DOI: 10.1534/genetics.120.303092. View

2.
Kumari R, Nambiar M, Shanbagh S, Raghavan S . Detection of G-quadruplex DNA using primer extension as a tool. PLoS One. 2015; 10(3):e0119722. PMC: 4370603. DOI: 10.1371/journal.pone.0119722. View

3.
Choi B, Lee H . DNA-RNA hybrid G-quadruplex tends to form near the 3' end of telomere overhang. Biophys J. 2022; 121(15):2962-2980. PMC: 9388385. DOI: 10.1016/j.bpj.2022.06.026. View

4.
Wu R, Zheng K, Zhang J, Hao Y, Tan Z . Formation of DNA:RNA hybrid G-quadruplex in bacterial cells and its dominance over the intramolecular DNA G-quadruplex in mediating transcription termination. Angew Chem Int Ed Engl. 2015; 54(8):2447-51. DOI: 10.1002/anie.201408719. View

5.
Zheng K, Xiao S, Liu J, Zhang J, Hao Y, Tan Z . Co-transcriptional formation of DNA:RNA hybrid G-quadruplex and potential function as constitutional cis element for transcription control. Nucleic Acids Res. 2013; 41(10):5533-41. PMC: 3664831. DOI: 10.1093/nar/gkt264. View