MT-TF

mitochondrially encoded tRNA phenylalanine
mitochondrially encoded tRNA phenylalanine
Identifiers
Symbol	MT-TF
Alt. symbols	MTTF
NCBI gene	4558
HGNC	7481
RefSeq	NC_001807
Other data
Locus	Chr. MT

Last updated August 19, 2023

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

Structure

The MT-TF gene is located on the p arm of the mitochondrial DNA at position 12 and it spans 71 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-TF is a small transfer RNA (human mitochondrial map position 577-647) that transfers the amino acid phenylalanine to a growing polypeptide chain at the ribosome site of protein synthesis during translation.

Clinical significance

Mutations in MT-TF can result in mitochondrial deficiencies and associated disorders, including Myoclonic epilepsy with ragged-red fibers (MERRF), Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS), Juvenile myopathy, encephalopathy, lactic acidosis, and stroke.^[4]

Myoclonic epilepsy with ragged-red fibers (MERRF)

Mutations in the MT-TF 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:^[4]

A 611G-A transition in MT-TF was found in a patient with MERRF.^[5]

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

Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) is a condition that affects many of the body's systems, particularly the brain and nervous system (encephalo-) and muscles (myopathy). The signs and symptoms of this disorder most often appear in childhood following a period of normal development, although they can begin at any age. Early symptoms may include muscle weakness and pain, recurrent headaches, loss of appetite, vomiting, and seizures. Most affected individuals experience stroke-like episodes beginning before age 40. These episodes often involve temporary muscle weakness on one side of the body (hemiparesis), altered consciousness, vision abnormalities, seizures, and severe headaches resembling migraines. Repeated stroke-like episodes can progressively damage the brain, leading to vision loss, problems with movement, and a loss of intellectual function (dementia).^[6]

A patient with a mutation in the 583G-A position of the MT-TF gene exhibited symptoms of acute episodes of headaches, photophobia, vomiting, and a fully recovered left arm focal motor fitting.^[7]

Complex IV Deficiency

MT-TF 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.^[8] 622G>A mutations have been associated with the deficiency.^[9]

Related Research Articles

Mitochondrial myopathies are types of myopathies associated with mitochondrial disease. On biopsy, the muscle tissue of patients with these diseases usually demonstrate "ragged red" muscle fibers. These ragged-red fibers contain mild accumulations of glycogen and neutral lipids, and may show an increased reactivity for succinate dehydrogenase and a decreased reactivity for cytochrome c oxidase. Inheritance was believed to be maternal. It is now known that certain nuclear DNA deletions can also cause mitochondrial myopathy such as the OPA1 gene deletion. There are several subcategories of mitochondrial myopathies.

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.

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.

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 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.

MT-ND5 is a gene of the mitochondrial genome coding for the NADH-ubiquinone oxidoreductase chain 5 protein (ND5). The ND5 protein is a subunit of NADH dehydrogenase (ubiquinone), which is located in the mitochondrial inner membrane and is the largest of the five complexes of the electron transport chain. Variations in human MT-ND5 are associated with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) as well as some symptoms of Leigh's syndrome and Leber's hereditary optic neuropathy (LHON).

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

↑ 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.
↑ "MT-TF mitochondrially encoded tRNA phenylalanine [Homo sapiens (human)] - Gene - NCBI". www.ncbi.nlm.nih.gov.
↑ "transfer RNA / tRNA". Scitable. Nature Education.
1 2 "MT-TF gene". Genetics Home Reference. U.S. National Library of Medicine.
↑ Mancuso M, Filosto M, Mootha VK, Rocchi A, Pistolesi S, Murri L, DiMauro S, Siciliano G (June 2004). "A novel mitochondrial tRNAPhe mutation causes MERRF syndrome". Neurology. 62 (11): 2119–21. doi:10.1212/01.wnl.0000127608.48406.f1. PMID 15184630. S2CID 12423569.
↑ "Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes". Genetics Home Reference. U.S. National Library of Medicine.
↑ Shapira Y, Cederbaum SD, Cancilla PA, Nielsen D, Lippe BM (July 1975). "Familial poliodystrophy, mitochondrial myopathy, and lactate acidemia". Neurology. 25 (7): 614–21. doi:10.1212/wnl.25.7.614. PMID 1171391. S2CID 39471179.
↑ "Cytochrome c oxidase deficiency". Genetics Home Reference. This article incorporates text from this source, which is in the public domain .
↑ Deschauer M, Swalwell H, Strauss M, Zierz S, Taylor RW (June 2006). "Novel mitochondrial transfer RNA(Phe) gene mutation associated with late-onset neuromuscular disease". Archives of Neurology. 63 (6): 902–5. doi:10.1001/archneur.63.6.902. PMID 16769874.