MT-TV (mitochondrial)

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

mitochondrially encoded tRNA valine
Identifiers
SymbolMT-TV
Alt. symbolsMTTV
NCBI gene4577
HGNC7500
OMIM590105
RefSeqNC_001807
Other data
LocusChr. MT

Structure

The MT-TV gene is located on the p arm of the non-nuclear mitochondrial DNA at position 12 and it spans 69 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-TV is a small 69 nucleotide RNA (human mitochondrial map position 1602-1670) that transfers the amino acid valine to a growing polypeptide chain at the ribosome site of protein synthesis during translation.

In animals, more specifically vertebrates, MT-tRNAVal performs an integral structual role for the mitoribosome by filling in the position of a missing 5S mitoribosomal RNA.[4]

Clinical significance

Mutations in MT-TV which impair oxidate phosphorylation result in 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. Two specific mutations of 1642G>A and 1644G>A have been found to result in the disease.[5]

Changes in the gene have also been associated with Leigh's syndrome, a progressive brain disorder characterized by vomiting, seizures, delayed development, muscle weakness, problems with movement, heart disease, kidney problems, and difficulty breathing. Symptoms typically appear in infancy or early childhood. A 1624C>T mutation has been linked to this disease.[6]

Other clinical manifestations associated with MT-TV mutations have included recurrent migraine headaches, muscle weakness and poor coordination, hearing loss, learning disabilities, dementia, and more. It has not been found why such mutations cause symptoms of these diseases.[5] A 1606A>G mutation resulted in ataxia accompanied by progressive seizures, mental deterioration, and hearing loss.[7] Cardiomyopathy, which weakens and enlarges the heart muscle, has also been reported in a small number of affected individuals.[5]

References
  1. Anderson S, Bankier AT, Barrell BG, de Bruijn MH, Coulson AR, Drouin J, et al. (April 1981). "Sequence and organization of the human mitochondrial genome". Nature. 290 (5806): 457–65. Bibcode:1981Natur.290..457A. doi:10.1038/290457a0. PMID 7219534. S2CID 4355527.
  2. "MT-TV mitochondrially encoded tRNA valine [Homo sapiens (human)] - Gene - NCBI". www.ncbi.nlm.nih.gov.
  3. "tRNA / transfer RNA". Learn Science at Scitable.
  4. Brown A, Amunts A, Bai XC, Sugimoto Y, Edwards PC, Murshudov G, et al. (November 2014). "Structure of the large ribosomal subunit from human mitochondria". Science. 346 (6210): 718–722. Bibcode:2014Sci...346..718B. doi:10.1126/science.1258026. PMC 4246062. PMID 25278503.
  5. "MT-TH gene". Genetics Home Reference. This article incorporates text from this source, which is in the public domain.
  6. McFarland R, Clark KM, Morris AA, Taylor RW, Macphail S, Lightowlers RN, Turnbull DM (February 2002). "Multiple neonatal deaths due to a homoplasmic mitochondrial DNA mutation". Nature Genetics. 30 (2): 145–6. doi:10.1038/ng819. PMID 11799391. S2CID 10940372.
  7. Tiranti V, D'Agruma L, Pareyson D, Mora M, Carrara F, Zelante L, et al. (January 1998). "A novel mutation in the mitochondrial tRNA(Val) gene associated with a complex neurological presentation". Annals of Neurology. 43 (1): 98–101. doi:10.1002/ana.410430116. PMID 9450773. S2CID 25775432.

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

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