MT-TL1

Last updated
mitochondrially encoded tRNA leucine 1 (UUA/G)
Identifiers
SymbolMT-TL1
Alt. symbolsMTTL1
NCBI gene 4567
HGNC 7490
OMIM 590050
RefSeq NC_001807
Other data
Locus Chr. MT

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]

Contents

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. Also, some studies showed that the MT-TL1 gene pathogenic variants could be attributed to the alterations of mTERF binding efficiency. [4]

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). [5] 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] A common mutation is A3243G. This mutation has been theorized to be associated with several other mitochondrial diseases, [7] including diabetes mellitus and deafness. [8] [9] Diabetes mellitus and deafness is characterized by diabetes combined with hearing loss, particularly of high pitches. Additional symptoms include muscle weakness (myopathy) and various problems with a patient's eyes, heart, or kidneys. [10]

Other rare point variants on MT-TL1 gene were also described: m.3271 T > C, m.3291 T > C, m.3303 C > T, m.3256 C > T, and m.3260 A>G. [4]

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. [11]

See also

Related Research Articles

<span class="mw-page-title-main">Mitochondrial myopathy</span> Medical condition

Mitochondrial myopathies are types of myopathies associated with mitochondrial disease. Adenosine triphosphate (ATP), the chemical used to provide energy for the cell, cannot be produced sufficiently by oxidative phosphorylation when the mitochondrion is either damaged or missing necessary enzymes or transport proteins. With ATP production deficient in mitochondria, there is an over-reliance on anaerobic glycolysis which leads to lactic acidosis either at rest or exercise-induced.

<span class="mw-page-title-main">MELAS syndrome</span> Medical condition

Mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) is one of the family of mitochondrial diseases, which also include MIDD, MERRF syndrome, and Leber's hereditary optic neuropathy. It was first characterized under this name in 1984. A feature of these diseases is that they are caused by defects in the mitochondrial genome which is inherited purely from the female parent. The most common MELAS mutation is mitochondrial mutation, mtDNA, referred to as m.3243A>G.

<span class="mw-page-title-main">MERRF syndrome</span> Medical condition

MERRF syndrome is a mitochondrial disease. It is extremely rare, and has varying degrees of expressivity owing to heteroplasmy. MERRF syndrome affects different parts of the body, particularly the muscles and nervous system. The signs and symptoms of this disorder appear at an early age, generally childhood or adolescence. The causes of MERRF syndrome are difficult to determine, but because it is a mitochondrial disorder, it can be caused by the mutation of nuclear DNA or mitochondrial DNA. The classification of this disease varies from patient to patient, since many individuals do not fall into one specific disease category. The primary features displayed on a person with MERRF include myoclonus, seizures, cerebellar ataxia, myopathy, and ragged red fibers (RRF) on muscle biopsy, leading to the disease's name. Secondary features include dementia, optic atrophy, bilateral deafness, peripheral neuropathy, spasticity, or multiple lipomata. Mitochondrial disorders, including MERRFS, may present at any age.

<span class="mw-page-title-main">Diabetes and deafness</span> Medical condition

Diabetes and deafness (DAD) or maternally inherited diabetes and deafness (MIDD) or mitochondrial diabetes is a subtype of diabetes which is caused from a mutation in mitochondrial DNA, which consists of a circular genome. It is associated with the genes MT-TL1, MT-TE, and MT-TK. The point mutation at position 3243A>G, in gene MT-TL1 encoding tRNA leucine 1, is most common. Because mitochondrial DNA is contributed to the embryo by the oocyte and not by spermatozoa, this disease is inherited from maternal family members only. As indicated by the name, MIDD is characterized by diabetes and sensorineural hearing loss. Some individuals also experience more systemic symptoms including eye, muscle, brain, kidney, heart, and gastrointestinal abnormalities, similiar to other mitochondrial diseases.

<span class="mw-page-title-main">MT-RNR1</span> SSU rRNA of the mitochondrial ribosome

Mitochondrially encoded 12S ribosomal RNA is the SSU rRNA of the mitochondrial ribosome. In humans, 12S is encoded by the MT-RNR1 gene and is 959 nucleotides long. MT-RNR1 is one of the 37 genes contained in animal mitochondria genomes. Their 2 rRNA, 22 tRNA and 13 mRNA genes are very useful in phylogenetic studies, in particular the 12S and 16S rRNAs. The 12S rRNA is the mitochondrial homologue of the prokaryotic 16S and eukaryotic nuclear 18S ribosomal RNAs. Mutations in the MT-RNR1 gene may be associated with hearing loss. The rRNA gene also encodes a peptide MOTS-c, also known as Mitochondrial-derived peptide MOTS-c or Mitochondrial open reading frame of the 12S rRNA-c.

Mitochondrially encoded tRNA histidine, also known as MT-TH, is a transfer RNA which, in humans, is encoded by the mitochondrial MT-TH gene.

<span class="mw-page-title-main">MT-ND1</span> Mitochondrial gene coding for a protein involved in the respiratory chain

MT-ND1 is a gene of the mitochondrial genome coding for the NADH-ubiquinone oxidoreductase chain 1 (ND1) protein. The ND1 protein is a subunit of NADH dehydrogenase, which is located in the mitochondrial inner membrane and is the largest of the five complexes of the electron transport chain. Variants of the human MT-ND1 gene are associated with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS), Leigh's syndrome (LS), Leber's hereditary optic neuropathy (LHON) and increases in adult BMI.

<span class="mw-page-title-main">LARS2</span> Protein-coding gene in the species Homo sapiens

Probable leucyl-tRNA synthetase, mitochondrial is an enzyme that in humans is encoded by the LARS2 gene.

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

Mitochondrially encoded tRNA aspartic acid also known as MT-TD is a transfer RNA which in humans is encoded by the mitochondrial MT-TD gene.

Mitochondrially encoded tRNA glutamic acid also known as MT-TE is a transfer RNA which in humans is encoded by the mitochondrial MT-TE gene. MT-TE is a small 69 nucleotide RNA that transfers the amino acid glutamic acid to a growing polypeptide chain at the ribosome site of protein synthesis during translation.

Mitochondrially encoded tRNA phenylalanine also known as MT-TF is a transfer RNA which in humans is encoded by the mitochondrial MT-TF gene.

Mitochondrially encoded tRNA isoleucine also known as MT-TI is a transfer RNA which in humans is encoded by the mitochondrial MT-TI gene.

Mitochondrially encoded tRNA lysine also known as MT-TK is a transfer RNA which in humans is encoded by the mitochondrial MT-TK gene.

Mitochondrially encoded tRNA leucine 2 (CUN) also known as MT-TL2 is a transfer RNA which in humans is encoded by the mitochondrial MT-TL2 gene.

Mitochondrially encoded tRNA asparagine also known as MT-TN is a transfer RNA which in humans is encoded by the mitochondrial MT-TN gene.

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

Mitochondrially encoded tRNA threonine also known as MT-TT is a transfer RNA which in humans is encoded by the mitochondrial MT-TT gene.

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

Mitochondrially encoded tRNA tyrosine, also known as MT-TY, is a transfer RNA which in humans is encoded by the mitochondrial MT-TY gene.

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. Bibcode:1981Natur.290..457A. doi:10.1038/290457a0. PMID   7219534. S2CID   4355527.
  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. 1 2 Bulduk BK, Kiliç HB, Bekircan-Kurt CE, Haliloğlu G, Erdem Özdamar S, Topaloğlu H, Kocaefe YÇ (March 2020). "A Novel Amplification-Refractory Mutation System-PCR Strategy to Screen MT-TL1 Pathogenic Variants in Patient Repositories". Genetic Testing and Molecular Biomarkers. 24 (3): 165–170. doi:10.1089/gtmb.2019.0079. PMID   32167396. S2CID   212693790.
  5. ↑ 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.
  6. ↑ "MT-TH gene". Genetics Home Reference.PD-icon.svg This article incorporates text from this source, which is in the public domain .
  7. ↑ 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. S2CID   43823627.
  8. ↑ 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. S2CID   34540249.
  9. ↑ 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. Bibcode:2012PLoSO...734956M. 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.
  10. ↑ 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.
  11. ↑ 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. S2CID   38721676.

Further reading

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