Correction of ATM gene function by aminoglycoside-induced read-through of premature termination codons.
Approximately 14% of genetic mutations in patients with ataxia-telangiectsia (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.
Lai
Chih-Hung
CH
Department of Pathology and Laboratory Medicine, The David Geffen School of Medicine at UCLA, Los Angeles, CA 90095-1732, USA.
Chun
Helen H
HH
Nahas
Shareef A
SA
Mitui
Midori
M
Gamo
Kristin M
KM
Du
Liutao
L
Gatti
Richard A
RA
D000617:Aminoglycosides / Q000494:pharmacology*; D001260:Ataxia Telangiectasia / Q000235:genetics / Q000378:metabolism; D064007:Ataxia Telangiectasia Mutated Proteins; D001483:Base Sequence; D018797:Cell Cycle Proteins; D002460:Cell Line; D018389:Codon, Nonsense / Q000187:drug effects* / Q000235:genetics*; D004247:DNA / Q000096:biosynthesis / Q000235:genetics; D004268:DNA-Binding Proteins; D005839:Gentamicins / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D010303:Paromomycin / Q000494:pharmacology; D017354:Point Mutation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics*; D011836:Radiation Tolerance / Q000235:genetics; D014031:Tobramycin / Q000494:pharmacology; D025521:Tumor Suppressor Proteins
D000617:Aminoglycosides; D018797:Cell Cycle Proteins; D018389:Codon, Nonsense; D004268:DNA-Binding Proteins; D005839:Gentamicins; D025521:Tumor Suppressor Proteins; D010303:Paromomycin; D004247:DNA; C010680:antibiotic G 418; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D017346:Protein Serine-Threonine Kinases; D014031:Tobramycin