Advances in functional mechanisms of genomic G-quadruplex structures in transcriptional regulation

As a canonical non-B DNA secondary structure, the G-quadruplex (G4) dynamically regulates core biological processes, including telomere homeostasis, DNA replication and gene transcription/translation-through its unique four-stranded conformation. The significant enrichment of G4 structures in regulatory regions, particularly promoter regions within mammalian genomes reveals their critical role in transcriptional regulation. In this review, we focus on the dynamic formation mechanisms and transcriptional regulatory functions of endogenous G4 structures, systematically elucidating their three molecular pathways in modulating gene expression: (1) orchestrating spatial assembly of transcription activation complexes; (2) dynamically regulating epigenetic modifications, includinghistone alterations and DNA methylation; (3) remodeling three-dimensional chromatin architecture to establish transcriptionally active microenvironments. By integrating advancements in G4 topological characterization techniques and dynamic equilibrium networks, this work highlights the role of the G4 as a critical cis-regulatory element and provides a theoretical framework for developing G4-targeted therapeutic strategies.