MT-TR explained

mitochondrially encoded tRNA arginine
Hgncid:	7496
Symbol:	MT-TR
Altsymbols:	MTTR
Entrezgene:	4573
Refseq:	NC_001807
Chromosome:	MT

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

Structure

The MT-TR gene is located on the p arm of the non-nuclear mitochondrial DNA at position 12 and it spans 65 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-TR is a small 65 nucleotide RNA (human mitochondrial map position 10405-10469) that transfers the amino acid arginine to a growing polypeptide chain at the ribosome site of protein synthesis during translation.

Clinical significance

Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS)

Mutations in MT-TR have been associated with 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.^[4] Mutations in MT-TR associated with the disease have included 10450A-G^[5] and 10438A-G.^[6]

Cytochrome c oxidase deficiency

MT-TR mutations have been associated with complex IV deficiency of the mitochondrial respiratory chain, also known as the cytochrome c oxidase deficiency. Cytochrome c oxidase deficiency is a rare genetic condition that can affect multiple parts of the body, including skeletal muscles, the heart, the brain, or the liver. Common clinical manifestations include myopathy, hypotonia, and encephalomyopathy, lactic acidosis, and hypertrophic cardiomyopathy.^[7] A 10437 G>A mutation has been found with a patient with the deficiency.^[8]

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-TR mitochondrially encoded tRNA arginine [Homo sapiens (human)] - Gene - NCBI ]. www.ncbi.nlm.nih.gov . en.
3. Web site: tRNA / transfer RNA . Learn Science at Scitable .
4. Web site: Reference . Genetics Home . MT-TH gene . Genetics Home Reference . en.
5. 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 . Functional consequences of mitochondrial tRNA Trp and tRNA Arg mutations causing combined OXPHOS defects . European Journal of Human Genetics . 18 . 3 . 324–9 . March 2010 . 19809478 . 10.1038/ejhg.2009.169 . 2987211 .
6. Uusimaa J, Finnilä S, Remes AM, Rantala H, Vainionpää L, Hassinen IE, Majamaa K . Molecular epidemiology of childhood mitochondrial encephalomyopathies in a Finnish population: sequence analysis of entire mtDNA of 17 children reveals heteroplasmic mutations in tRNAArg, tRNAGlu, and tRNALeu(UUR) genes . Pediatrics . 114 . 2 . 443–50 . August 2004 . 15286228 . 10.1542/peds.114.2.443.
7. Web site: Reference . Genetics Home . Cytochrome c oxidase deficiency . Genetics Home Reference . en.
8. Roos S, Darin N, Kollberg G, Andersson Grönlund M, Tulinius M, Holme E, Moslemi AR, Oldfors A . A novel mitochondrial tRNA Arg mutation resulting in an anticodon swap in a patient with mitochondrial encephalomyopathy . European Journal of Human Genetics . 21 . 5 . 571–3 . May 2013 . 22781096 . 10.1038/ejhg.2012.153 . 3641373 .