DNA minor groove at guanine-rich sequences (GC-rich DNA minor groove)

The DNA minor groove at guanine-rich (GC-rich) sequences is a specific structural motif within the DNA double helix that serves as a target for several natural and synthetic small molecules. Unlike many minor groove binders that prefer adenine-thymine (AT) tracts, certain antitumor antibiotics like Mithramycin A and Chromomycin A3 exhibit high affinity for GC-rich regions, typically requiring divalent cations like magnesium for stable complex formation (PMID: 11473578). Biologically, these GC-rich sequences are frequently found in the promoter regions of housekeeping genes and oncogenes, often serving as binding sites for the Sp1 transcription factor family (PMID: 15548700). When drugs bind to this site, they sterically hinder the association of transcription factors and RNA polymerase, leading to the potent inhibition of gene transcription and subsequent cell cycle arrest or apoptosis (PMID: 24513105). This target is particularly relevant in oncology, where it has been exploited to treat cancers such as Ewing sarcoma and testicular carcinoma by downregulating key drivers like EWS-FLI1 (PMID: 21653233). However, the therapeutic use of agents targeting the GC-rich minor groove is often constrained by severe systemic toxicities, including hepatotoxicity and hemorrhagic diathesis, due to a lack of absolute sequence specificity (PMID: 7505851).

Other names

GC-rich DNA minor grooveGuanine-cytosine rich DNA minor grooveMinor groove of GC-rich DNA

Binding to the minor groove of GC-rich DNA sequences, often mediated by divalent metal ions, which sterically displaces transcription factors such as Sp1 and inhibits RNA polymerase activity.