MT-TI

Last updated
mitochondrially encoded tRNA isoleucine
Identifiers
SymbolMT-TI
Alt. symbolsMTTI
NCBI gene 4565
HGNC 7488
RefSeq NC_001807
Other data
Locus Chr. MT

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

Contents

Structure

The MT-TI gene is located on the p arm of the 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-TI is a small 69 nucleotide RNA (human mitochondrial map position 4263-4331) that transfers the amino acid isoleucine to a growing polypeptide chain at the ribosome site of protein synthesis during translation.

Clinical significance

Mutations in MT-TI can result in multiple mitochondrial deficiencies and associated disorders.

Myoclonic epilepsy with ragged-red fibers (MERRF)

Mutations in the MT-TI gene have been associated with myoclonic epilepsy with ragged-red fibers (MERRF). Myoclonic epilepsy with ragged-red fibers (MERRF) is a 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 symptoms include, myoclonus, myopathy, spasticity, epilepsy, peripheral neuropathy, dementia, ataxia, atrophy, and more. [4]

Cardiomyopathy

Mutations in the MT-TI gene may also cause cardiomyopathy, a disorder of the heart characterized by the thickening of the heart, usually in the interventricular septum, which results in a weakened heart muscle that is unable to pump blood effectively. It is unclear why such mutations result in the symptoms of isolated cardiomyopathy. [5] Mutations of 4300A>G, 4295A>G, 4269A>G, and 4317A>G in the MT-TI gene have been found in patients with cardiomyopathy in varying severities and onset. [6] [7] [8] [9]

Complex IV Deficiency

MT-TI 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. [10] A patient with a 4269A>G mutation in MT-TI was found with the deficiency. [11]

Related Research Articles

MELAS syndrome Medical condition

Mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) is one of the family of mitochondrial diseases, which also include 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.

<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">MT-RNR1</span> SSU rRNA of the mitochondrial ribosome

Mitochondrially encoded 12S ribosomal RNA, also known as Mitochondrial-derived peptide MOTS-c or Mitochondrial open reading frame of the 12S rRNA-c 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.

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.

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

Cytochrome c oxidase subunit I Enzyme of the respiratory chain encoded by the mitochondrial genome

Cytochrome c oxidase I (COX1) also known as mitochondrially encoded cytochrome c oxidase I (MT-CO1) is a protein that in humans is encoded by the MT-CO1 gene. In other eukaryotes, the gene is called COX1, CO1, or COI. Cytochrome c oxidase I is the main subunit of the cytochrome c oxidase complex. Mutations in MT-CO1 have been associated with Leber's hereditary optic neuropathy (LHON), acquired idiopathic sideroblastic anemia, Complex IV deficiency, colorectal cancer, sensorineural deafness, and recurrent myoglobinuria.

Cytochrome c oxidase subunit II Enzyme of the respiratory chain encoded by the mitochondrial genome

Cytochrome c oxidase subunit 2, also known as cytochrome c oxidase polypeptide II, is a protein that in humans is encoded by the MT-CO2 gene. Cytochrome c oxidase subunit II, abbreviated COXII, COX2, COII, or MT-CO2, is the second subunit of cytochrome c oxidase. It is also one of the three mitochondrial DNA (mtDNA) encoded subunits of respiratory complex IV.

Cytochrome c oxidase subunit III Enzyme of the respiratory chain encoded by the mitochondrial genome

Cytochrome c oxidase subunit III (COX3) is an enzyme that in humans is encoded by the MT-CO3 gene. It is one of main transmembrane subunits of cytochrome c oxidase. It is also one of the three mitochondrial DNA (mtDNA) encoded subunits of respiratory complex IV. Variants of it have been associated with isolated myopathy, severe encephalomyopathy, Leber hereditary optic neuropathy, mitochondrial complex IV deficiency, and recurrent myoglobinuria.

SURF1 Protein-coding gene in the species Homo sapiens

Surfeit locus protein 1 (SURF1) is a protein that in humans is encoded by the SURF1 gene. The protein encoded by SURF1 is a component of the mitochondrial translation regulation assembly intermediate of cytochrome c oxidase complex, which is involved in the regulation of cytochrome c oxidase assembly. Defects in this gene are a cause of Leigh syndrome, a severe neurological disorder that is commonly associated with systemic cytochrome c oxidase deficiency, and Charcot-Marie-Tooth disease 4K (CMT4K).

COX6B1 Protein-coding gene in the species Homo sapiens

Cytochrome c oxidase subunit 6B1 is an enzyme that in humans is encoded by the COX6B1 gene. Cytochrome c oxidase 6B1 is a subunit of the cytochrome c oxidase complex, also known as Complex IV, the last enzyme in the mitochondrial electron transport chain. Mutations of the COX6B1 gene are associated with severe infantile encephalomyopathy and mitochondrial complex IV deficiency (MT-C4D).

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 glycine also known as MT-TG is a transfer RNA which in humans is encoded by the mitochondrial MT-TG 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.

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-TI mitochondrially encoded tRNA isoleucine [Homo sapiens (human)] - Gene - NCBI". www.ncbi.nlm.nih.gov.
  3. "tRNA / transfer RNA". Learn Science at Scitable.
  4. "Myoclonic epilepsy with ragged-red fibers". Genetics Home Reference. U.S. National Library of Medicine.PD-icon.svgThis article incorporates text from this source, which is in the public domain .
  5. "Familial hypertrophic cardiomyopathy". Genetics Home Reference. U.S. National Library of Medicine.PD-icon.svgThis article incorporates text from this source, which is in the public domain .
  6. Tanaka M, Ino H, Ohno K, Hattori K, Sato W, Ozawa T, et al. (December 1990). "Mitochondrial mutation in fatal infantile cardiomyopathy". Lancet. 336 (8728): 1452. doi:10.1016/0140-6736(90)93162-I. PMID   1978914. S2CID   27652968.
  7. Taniike M, Fukushima H, Yanagihara I, Tsukamoto H, Tanaka J, Fujimura H, et al. (July 1992). "Mitochondrial tRNA(Ile) mutation in fatal cardiomyopathy". Biochemical and Biophysical Research Communications. 186 (1): 47–53. doi:10.1016/S0006-291X(05)80773-9. PMID   1632786.
  8. Merante F, Myint T, Tein I, Benson L, Robinson BH (1996). "An additional mitochondrial tRNA(Ile) point mutation (A-to-G at nucleotide 4295) causing hypertrophic cardiomyopathy". Human Mutation. 8 (3): 216–22. doi:10.1002/(SICI)1098-1004(1996)8:3<216::AID-HUMU4>3.0.CO;2-7. PMID   8889580. S2CID   34527275.
  9. Taylor RW, Giordano C, Davidson MM, d'Amati G, Bain H, Hayes CM, et al. (May 2003). "A homoplasmic mitochondrial transfer ribonucleic acid mutation as a cause of maternally inherited hypertrophic cardiomyopathy". Journal of the American College of Cardiology. 41 (10): 1786–96. doi: 10.1016/S0735-1097(03)00300-0 . PMID   12767666.
  10. Reference, Genetics Home. "Cytochrome c oxidase deficiency". Genetics Home Reference.PD-icon.svgThis article incorporates text from this source, which is in the public domain .
  11. Kaido M, Fujimura H, Taniike M, Yoshikawa H, Toyooka K, Yorifuji S, Inui K, Okada S, Sparaco M, Yanagihara T (August 1995). "Focal cytochrome c oxidase deficiency in the brain and dorsal root ganglia in a case with mitochondrial encephalomyopathy (tRNA(Ile) 4269 mutation): histochemical, immunohistochemical, and ultrastructural study". Journal of the Neurological Sciences. 131 (2): 170–6. doi:10.1016/0022-510X(95)00111-E. PMID   7595643. S2CID   41493869.

Further reading

Finsterer, J (January 2003). "Mitochondriopathy mimicking amyotrophic lateral sclerosis". The Neurologist. 9 (1): 45–8. doi:10.1097/01.nrl.0000038589.58012.a8. PMID   12801431. S2CID   43440359.

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