Adenine-thymine-rich DNA (AT-rich DNA) (AT-rich DNA)

Adenine-thymine-rich DNA (AT-rich DNA) consists of genomic segments characterized by a high density of adenine and thymine base pairs, which results in a lower melting temperature and a distinctively narrow, deep minor groove (Geierstanger & Wemmer, 1995). These regions are biologically significant as they often serve as regulatory hubs, including TATA boxes in promoters, origins of replication, and scaffold/matrix attachment regions (MARs) that organize chromatin structure (Nelson et al., 1987). Because of their unique structural geometry, AT-rich tracts serve as specific binding sites for a class of small molecules known as minor groove binders (MGBs) (Dervan, 1986). Drugs targeting these regions, such as netropsin, distamycin, or pentamidine, exert their effects by physically blocking the access of essential DNA-binding proteins, including transcription factors and topoisomerases (Barrett et al., 1999). This interference can lead to the inhibition of gene expression, DNA replication, and cell division, making AT-rich DNA a target for anti-cancer, anti-parasitic, and anti-microbial therapies (Wemmer, 2000). However, the widespread occurrence of AT-rich sequences throughout the genome presents significant challenges regarding therapeutic selectivity and potential off-target toxicity (Nelson et al., 1987). Small molecules designed to recognize specific sequences within AT-rich tracts are being developed to improve the precision of these therapies (Dervan, 1986). Despite these efforts, the inherent risk of mutagenicity and systemic cytotoxicity remains a primary concern for drugs that interact directly with the genetic material.

Other names

AT-rich sequencesAT-rich regionsMinor groove AT-rich DNAAT-tractsAdenine-thymine-rich tracts

Minor groove binding that stabilizes the DNA duplex and competitively inhibits the binding of transcription factors, RNA polymerase, and topoisomerases (Dervan, 1986; Geierstanger & Wemmer, 1995).