Correction of ATM Gene Function by Aminoglycoside-Induced Read-Through of Premature Termination Codons

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 101; no. 44; pp. 15676 - 15681
• Main Authors: Lai, Chih-Hung, Chun, Helen H., Nahas, Shareef A., Mitui, Midori, Gamo, Kristin M., Du, Liutao, Gatti, Richard A., Klein, George
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 02-11-2004; National Acad Sciences
• Subjects: Aminoglycosides; Aminoglycosides - pharmacology; Ataxia telangiectasia; Ataxia Telangiectasia - genetics; Ataxia Telangiectasia - metabolism; Ataxia Telangiectasia Mutated Proteins; Base Sequence; Biological Sciences; Cell Cycle Proteins; Cell Line; Cell lines; Cellular immunity; Changes; Codon, Nonsense - drug effects; Codon, Nonsense - genetics; DNA; DNA - biosynthesis; DNA - genetics; DNA-Binding Proteins; Genes; Genetic mutation; Genetics; Gentamicins - pharmacology; Humans; In Vitro Techniques; Medical genetics; Mutation; Paromomycin - pharmacology; Patients; Plasmids; Point Mutation; Protein-Serine-Threonine Kinases - genetics; Radiation genetics; Radiation Tolerance - genetics; Stop codon; Tobramycin - pharmacology; Tumor Suppressor Proteins
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.0405155101

Approximately 14% of genetic mutations in patients with ataxiatelangiectsia (A-T) are single-nucleotide changes that result in primary premature termination codons (PTCs), either UAA, UAG, or UGA. The purpose of this study was to explore a potential therapeutic approach for this subset of patients by using aminoglycosides to induce PTC read-through, thereby restoring levels of full-length ATM (A-T mutated) protein. In experiments using a modified in vitro cDNA coupled transcription/translation protein truncation test, 13 A-T cell lines carrying PTC mutations in different contexts exhibited read-through expression of ATM fragments, with three of four aminoglycosides tested. In ex vivo experiments with lymphoblastoid cell lines, we used radiosensitivity, radioresistant DNA synthesis, and irradiation-induced autophosphorylation of ATM Ser-1981 to show that the aminoglycoside-induced full-length ATM protein was functional and corrected, to various extents, the phenotype of A-T cells. These results encourage further testing of other compounds in this class, as well as follow up animal studies. Because some A-T patients with 5-20% of normal levels of ATM protein show slower neurological progression, A-T may prove to be a good model for aminoglycoside-induced read-through therapy.