Stability and context of intercalated motifs (i-motifs) for biological applications

DNA is naturally dynamic and can self-assemble into alternative secondary structures including the intercalated motif (i-motif), a four-stranded structure formed in cytosine-rich DNA sequences. Until recently, i-motifs were thought to be unstable in physiological cellular environments. Studies demonstrating their existence in the human genome and role in gene regulation are now shining light on their biological relevance. Herein, we review the effects of epigenetic modifications on i-motif structure and stability, and biological factors that affect i-motif formation within cells. Furthermore, we highlight recent progress in targeting i-motifs with structure-specific ligands for biotechnology and therapeutic purposes. (C) 2022 Elsevier B.V. and Societe Francaise de Biochimie et Biologie Moleculaire (SFBBM). All rights reserved.

Automated summary

DNA is capable of forming alternative secondary structures, including the i-motif, which was previously believed to be unstable in cellular environments. Recent studies have shown the existence of i-motifs in the human genome and their role in gene regulation. This review discusses the effects of epigenetic modifications on i-motif structure, factors influencing i-motif formation in cells, and highlights the recent progress in targeting i-motifs for biotechnology and therapeutic purposes.