title: Suppression of the nonsense mutation in homozygous beta 0 thalassaemia.
abstract: The common form of beta thalassaemia associated with elevated haemoglobin A2 levels can be broadly classified as beta + or beta 0 type according to the presence or absence of beta-globin chain synthesis in the homozygous state. The molecular pathology of each type is heterogeneous. Apart from a subgroup of Indo-Pakistani patients, the beta-globin structural gene is intact in the majority of patients with beta 0 thalassaemia. The amount of beta-globin mRNA present in the reticulocytes of these patients varies: in some it is absent or barely detectable; in others, a substantial amount is present, but it is nonfunctional. We recently demonstrated that the molecular lesion in a Chinese patient with nonfunctional beta-globin mRNA was due to the mutation of the normal lysine codon AAG at amino acid 17 to the amber terminator codon UAG, which prematurely terminates the beta-globin chain. In the present study we demonstrate the first example of a nonsense mutation in humans which can be suppressed in vitro by the suppressor tRNA, as has been found in other eukaryotic cells and viruses.
mesh_terms: D003062:Codon; D005796:Genes; D009154:Mutation; D012343:RNA, Transfer / Q000378:metabolism; D012694:Serine / Q000235:genetics; D013489:Suppression, Genetic; D013789:Thalassemia / Q000235:genetics*
chemical_list: D003062:Codon; D012694:Serine; D012343:RNA, Transfer