Mutation, nonsense
A mutation (a change) in a base in the DNA that prematurely stops the translation (reading) of messenger RNA (mRNA) resulting in a polypeptide chain that ends prematurely and a protein product that is truncated (abbreviated) and incomplete and usually nonfunctional. The nonsense mutation converts a codon (a triplet of bases) that encodes an amino acid into a stop codon, one that specifies the termination of translation. There are three nonsense codons (UAG, UAA, and UGA) in mRNA. One of them comes normally at the end of each polypeptide. A nonsense codon is a stop codon which is out of place. Catching such a defective messenger RNA (mRNA) before a truncated and potentially harmful protein is synthesized is the job of what is called the nonsense-mediated mRNA decay (NMD) pathway.

Medical dictionary. 2011.

Look at other dictionaries:

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  • Mutation — A permanent change, a structural alteration, in the DNA or RNA. In humans and many other organisms, mutations occur in DNA. However, in retroviruses like HIV, mutations occur in RNA which is the genetic material of retroviruses. In most cases,… …   Medical dictionary

  • Nonsense (disambiguation) — Nonsense is an utterance or written text that does not in fact carry any identifiable meaning. Nonsense may also mean: Abstract nonsense, a term used by mathematicians to describe certain kinds of arguments and concepts in category theory In… …   Wikipedia

  • Nonsense mediated decay — Le Nonsense mediated decay ou NMD ou Dégradation des ARNm non sens est un mécanisme de contrôle qualité des ARN messagers cellulaires chez les eucaryotes[1]. Il vise a éliminer les ARNm qui comportent un codon stop prématuré, résultant soit d une …   Wikipédia en Français

  • nonsense mutation — nonsense mutation. См. нонсенс мутация. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • nonsense codon — (= nonsense triplet) The three codons, UAA (known as ochre), UAG (amber) and UGA (opal), that do not code for an amino acid but act as signals for the termination of protein synthesis. Any mutation that causes a base change which produces a… …   Dictionary of molecular biology

  • nonsense mutation — Mutation in coding DNA that prevents the protein from being synthesized …   Dictionary of molecular biology

  • Nonsense mutation — A mutation (a change) in a base in the DNA that prematurely stops the translation (reading) of messenger RNA (mRNA) resulting in a polypeptide chain that ends prematurely and a protein product that is truncated (abbreviated) and incomplete and… …   Medical dictionary

  • Nonsense suppressor — A nonsense suppressor is a tRNA mutation that suppresses the protein truncation resulting from a nonsense mutation. The nonsense suppressor is a tRNA gene (from Escherichia coli) which has a mutated anticodon. The mutated anticodon recognizes the …   Wikipedia

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