Double-stranded DNA at GpC-rich sequences (dsDNA (GpC-rich))

Double-stranded DNA at GpC-rich sequences is a critical molecular target for a class of cytotoxic antibiotics used in oncology. These genomic regions, characterized by high guanine and cytosine content, are often concentrated in CpG islands and gene promoters, making them essential for transcriptional regulation. Therapeutic agents like dactinomycin (actinomycin D) exhibit high affinity for these sites, intercalating their chromophore specifically between adjacent GpC base pairs (Source: PubChem CID 2019). This binding distorts the DNA structure and creates a stable drug-DNA complex that sterically hinders the movement of RNA polymerase along the template strand, effectively shutting down transcription (Source: NIH, National Cancer Institute). Other agents, such as mithramycin, bind within the minor groove of these GC-rich regions to achieve a similar inhibitory effect on gene expression (Source: PubMed, PMID: 11012903). Because GpC-rich regions are frequently located in the promoter regions of genes involved in cell growth and survival, targeting these sequences is particularly effective against rapidly proliferating malignant cells. However, the relative ubiquity of these sequences across the genome contributes to a narrow therapeutic index and significant systemic toxicities, including myelosuppression and severe tissue necrosis upon extravasation (Source: StatPearls, Dactinomycin).

Other names

GC-rich DNAGpC-rich DNA sequencesGuanine-cytosine rich DNAGpC-rich double-stranded DNA

Intercalation between adjacent GpC base pairs and minor groove binding, resulting in the physical obstruction of RNA polymerase and inhibition of DNA-directed RNA synthesis.