MT-TW

Mitochondrially encoded tRNA tryptophan also known as MT-TW is a transfer RNA which in humans is encoded by the mitochondrial MT-TW gene.[1]

mitochondrially encoded tRNA tryptophan
Identifiers
SymbolMT-TW
Alt. symbolsMTTW
NCBI gene4578
HGNC7501
RefSeqNC_001807
Other data
LocusChr. MT

Structure

The MT-TW gene is located on the p arm of the non-nuclear mitochondrial DNA at position 12 and it spans 68 base pairs.[2] The structure of a tRNA molecule is a distinctive folded structure which contains three hairpin loops and resembles a three-leafed clover.[3]

Function

MT-TW is a small 68 nucleotide RNA (human mitochondrial map position 5512-5579) that transfers the amino acid tryptophan to a growing polypeptide chain at the ribosome site of protein synthesis during translation.

Clinical significance

Mutations in MT-TW have been associated with Leigh's syndrome. Leigh's syndrome is a severe neurological disorder that usually becomes apparent in the first year of life. This condition is characterized by progressive loss of mental and movement abilities (psychomotor regression) and typically results in death within two to three years, usually due to respiratory failure. A small number of individuals do not develop symptoms until adulthood or have symptoms that worsen more slowly.[4] A patient with the syndrome associated with a mutation of 5537insT in the MT-TW gene exhibited symptoms of hypotonia, nystagmus, optic atrophy and seizures.[5]

Changes in MT-TW which impair oxidate phosphorylation also cause mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS). MELAS is a rare mitochondrial disorder known to affect many parts of the body, especially the nervous system and the brain. Symptoms of MELAS include recurrent severe headaches, muscle weakness (myopathy), hearing loss, stroke-like episodes with a loss of consciousness, seizures, and other problems affecting the nervous system.[6] Variants of the gene which cause the disease have included 5556G-A,[7] 5545C-T,[8] and 5521G-A.[9]

References
  1. Anderson S, Bankier AT, Barrell BG, de Bruijn MH, Coulson AR, Drouin J, Eperon IC, Nierlich DP, Roe BA, Sanger F, Schreier PH, Smith AJ, Staden R, Young IG (April 1981). "Sequence and organization of the human mitochondrial genome". Nature. 290 (5806): 457–65. doi:10.1038/290457a0. PMID 7219534.
  2. "MT-TW mitochondrially encoded tRNA tryptophan [Homo sapiens (human)] - Gene - NCBI". www.ncbi.nlm.nih.gov.
  3. "tRNA / transfer RNA". Learn Science at Scitable.
  4. Reference, Genetics Home. "Leigh syndrome". Genetics Home Reference. This article incorporates text from this source, which is in the public domain.
  5. Tulinius M, Moslemi AR, Darin N, Westerberg B, Wiklund LM, Holme E, Oldfors A (April 2003). "Leigh syndrome with cytochrome-c oxidase deficiency and a single T insertion nt 5537 in the mitochondrial tRNATrp gene". Neuropediatrics. 34 (2): 87–91. doi:10.1055/s-2003-39607. PMID 12776230.
  6. Reference, Genetics Home. "MELAS". Genetics Home Reference.
  7. Smits P, Mattijssen S, Morava E, van den Brand M, van den Brandt F, Wijburg F, Pruijn G, Smeitink J, Nijtmans L, Rodenburg R, van den Heuvel L (March 2010). "Functional consequences of mitochondrial tRNA Trp and tRNA Arg mutations causing combined OXPHOS defects". European Journal of Human Genetics. 18 (3): 324–9. doi:10.1038/ejhg.2009.169. PMC 2987211. PMID 19809478.
  8. Sacconi S, Salviati L, Nishigaki Y, Walker WF, Hernandez-Rosa E, Trevisson E, Delplace S, Desnuelle C, Shanske S, Hirano M, Schon EA, Bonilla E, De Vivo DC, DiMauro S, Davidson MM (June 2008). "A functionally dominant mitochondrial DNA mutation". Human Molecular Genetics. 17 (12): 1814–20. doi:10.1093/hmg/ddn073. PMC 2900892. PMID 18337306.
  9. Silvestri G, Rana M, DiMuzio A, Uncini A, Tonali P, Servidei S (June 1998). "A late-onset mitochondrial myopathy is associated with a novel mitochondrial DNA (mtDNA) point mutation in the tRNA(Trp) gene". Neuromuscular Disorders. 8 (5): 291–5. doi:10.1016/S0960-8966(98)00037-6. PMID 9673981.

This article incorporates text from the United States National Library of Medicine, which is in the public domain.

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