MT-TL1

Mitochondrially encoded tRNA leucine 1 (UUA/G) also known as MT-TL1 is a transfer RNA which in humans is encoded by the mitochondrial MT-TL1 gene.[1]

mitochondrially encoded tRNA leucine 1 (UUA/G)
Identifiers
SymbolMT-TL1
Alt. symbolsMTTL1
NCBI gene4567
HGNC7490
OMIM590050
RefSeqNC_001807
Other data
LocusChr. MT

Structure

The MT-TL1 gene is located on the p arm of the mitochondrial DNA at position 12 and it spans 75 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-TL1 is a small 75 nucleotide RNA (human mitochondrial map position 3230-3304) that transfers the amino acid leucine to a growing polypeptide chain at the ribosome site of protein synthesis during translation.

Clinical significance

Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes

Mutations in MT-TL1 can result in multiple mitochondrial deficiencies and associated disorders. It is associated with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS).[4] 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.[5] A common mutation is A3243G. This mutation has been theorized to be associated with several other mitochondrial diseases,[6] including diabetes mellitus and deafness.[7][8] Diabetes mellitus and deafness is characterized by diabetes combined with hearing loss, particularly of high pitches. Additional symptoms includemuscle weakness (myopathy) and various problems with a patient's eyes, heart, or kidneys.[9]

Complex I deficiency

MT-TP mutations may result in complex I deficiency of the mitochondrial respiratory chain, which may cause a wide variety of signs and symptoms affecting many organs and systems of the body, particularly the nervous system, the heart, and the muscles used for movement (skeletal muscles). These signs and symptoms can appear at any time from birth to adulthood. Phenotypes of the condition include encephalopathy, epilepsy, dystonia, hypotonia, myalgia, exercise intolerance, and more. A 3302A>G mutation has been found in a patient with the deficiency.[10]

See also

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-TI mitochondrially encoded tRNA isoleucine [Homo sapiens (human)] - Gene - NCBI". www.ncbi.nlm.nih.gov.
  3. "tRNA / transfer RNA". Learn Science at Scitable.
  4. Yasukawa T, Suzuki T, Ueda T, Ohta S, Watanabe K (February 2000). "Modification defect at anticodon wobble nucleotide of mitochondrial tRNAs(Leu)(UUR) with pathogenic mutations of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes". The Journal of Biological Chemistry. 275 (6): 4251–7. doi:10.1074/jbc.275.6.4251. PMID 10660592.
  5. "MT-TH gene". Genetics Home Reference. This article incorporates text from this source, which is in the public domain.
  6. Finsterer J (July 2007). "Genetic, pathogenetic, and phenotypic implications of the mitochondrial A3243G tRNALeu(UUR) mutation". Acta Neurologica Scandinavica. 116 (1): 1–14. doi:10.1111/j.1600-0404.2007.00836.x. PMID 17587249.
  7. Reardon W, Ross RJ, Sweeney MG, Luxon LM, Pembrey ME, Harding AE, Trembath RC (December 1992). "Diabetes mellitus associated with a pathogenic point mutation in mitochondrial DNA". Lancet. 340 (8832): 1376–9. doi:10.1016/0140-6736(92)92560-3. PMID 1360090.
  8. Mazzaccara C, Iafusco D, Liguori R, Ferrigno M, Galderisi A, Vitale D, et al. (2012-04-19). "Mitochondrial diabetes in children: seek and you will find it". PLOS ONE. 7 (4): e34956. doi:10.1371/journal.pone.0034956. PMC 3334935. PMID 22536343. We sequenced the mtDNA in the 11 probands, in their mothers and in 80 controls. We identified 33 diabetes-suspected mutations, 1/33 was 3243A>G. Most patients (91%) and their mothers had mutations in complex I and/or IV of the respiratory chain.
  9. Kameoka K, Isotani H, Tanaka K, Azukari K, Fujimura Y, Shiota Y, Sasaki E, Majima M, Furukawa K, Haginomori S, Kitaoka H, Ohsawa N (April 1998). "Novel mitochondrial DNA mutation in tRNA(Lys) (8296A-->G) associated with diabetes". Biochemical and Biophysical Research Communications. 245 (2): 523–7. doi:10.1006/bbrc.1998.8437. PMID 9571188.
  10. van den Bosch BJ, de Coo IF, Hendrickx AT, Busch HF, de Jong G, Scholte HR, Smeets HJ (October 2004). "Increased risk for cardiorespiratory failure associated with the A3302G mutation in the mitochondrial DNA encoded tRNALeu(UUR) gene". Neuromuscular Disorders. 14 (10): 683–8. doi:10.1016/j.nmd.2004.06.004. PMID 15351426.

Further reading

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

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