MT-TG explained

mitochondrially encoded tRNA glycine
Hgncid:7486
Symbol:MT-TG
Altsymbols:MTTG
Entrezgene:4563
Refseq:NC_001807
Chromosome:MT

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

Structure

The MT-TG gene is located on the p arm of the 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-TG is a small 68 nucleotide transfer RNA (human mitochondrial map position 9991-10058) that transfers the amino acid glycine to a growing polypeptide chain at the ribosome site of protein synthesis during translation.

Clinical significance

Myoclonic epilepsy with ragged-red fibers (MERRF)

Mutations in transfer RNAs have been found to lead to marked mitochondrial energy deficiency and a hindrance of mitochondrial proliferation, and defects in oxidative phosphorylation. Such defects may result in myoclonic epilepsy with ragged-red fibers (MERRF). Myoclonic epilepsy with ragged-red fibers (MERRF) is a rare mitochondrial disorder that affects many parts of the body, particularly the muscles and nervous system. In most cases, the signs and symptoms of this disorder appear during childhood or adolescence. The features of MERRF vary widely among affected individuals, even among members of the same family. Common clinical manifestations include myoclonus, myopathy, spasticity, epilepsy, peripheral neuropathy, dementia, ataxia, atrophy and more.[4] [5]

Familial hypertrophic cardiomyopathy

Mutations in the MT-TG gene has also been associated with familial hypertrophic cardiomyopathy. Familial hypertrophic cardiomyopathy is a heart condition characterized by thickening of the heart, usually in the interventricular septum. Common phenotypes include chest pain, shortness of breath, physical exertion, palpitations, lightheadedness, dizziness and fainting.[6] A family with a transition mutation of 9997T>C in the MT-TG gene exhibited familial hypertrophic cardiomyopathy.[7]

Further reading

Notes and 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 . Sequence and organization of the human mitochondrial genome . Nature . 290 . 5806 . 457–65 . April 1981 . 7219534 . 10.1038/290457a0 . 1981Natur.290..457A . 4355527 .
  2. Web site: MT-TG mitochondrially encoded tRNA glycine [Homo sapiens (human)] - Gene - NCBI ]. www.ncbi.nlm.nih.gov . en.
  3. Web site: tRNA / transfer RNA Learn Science at Scitable . www.nature.com . en.
  4. Web site: Myoclonic epilepsy with ragged-red fibers . Genetics Home Reference . U.S. National Library of Medicine .
  5. Graham BH, Waymire KG, Cottrell B, Trounce IA, MacGregor GR, Wallace DC . A mouse model for mitochondrial myopathy and cardiomyopathy resulting from a deficiency in the heart/muscle isoform of the adenine nucleotide translocator . Nature Genetics . 16 . 3 . 226–34 . July 1997 . 9207786 . 10.1038/ng0797-226 . 7285265 .
  6. Web site: Familial hypertrophic cardiomyopathy . Genetics Home Reference . U.S. National Library of Medicine .
  7. Merante F, Tein I, Benson L, Robinson BH . Maternally inherited hypertrophic cardiomyopathy due to a novel T-to-C transition at nucleotide 9997 in the mitochondrial tRNA(glycine) gene . American Journal of Human Genetics . 55 . 3 . 437–46 . September 1994 . 8079988 . 1918404 .