MT-TL1

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title: "MT-TL1" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public description: "Transfer RNA in the species Homo sapiens" topic_path: "uncategorized" source: "https://en.wikipedia.org/wiki/MT-TL1" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Transfer RNA in the species Homo sapiens ::

::data[format=table title="infobox protein"]

Field	Value
Name	mitochondrially encoded tRNA leucine 1 (UUA/G)
HGNCid	7490
Symbol	MT-TL1
AltSymbols	MTTL1
EntrezGene	4567
OMIM	590050
RefSeq	NC_001807
Chromosome	MT
::

|Name=mitochondrially encoded tRNA leucine 1 (UUA/G) |caption= |image= |width= |HGNCid=7490 |Symbol=MT-TL1 |AltSymbols=MTTL1 |EntrezGene=4567 |OMIM=590050 |RefSeq= NC_001807 |UniProt= |PDB= |ECnumber= |Chromosome=MT |Arm= |Band= |LocusSupplementaryData= 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.

Structure

The MT-TL1 gene is located on the p arm of the mitochondrial DNA at position 12 and it spans 75 base pairs. The structure of a tRNA molecule is a distinctive folded structure which contains three hairpin loops and resembles a three-leafed clover.

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.

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). 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. A common mutation is A3243G. This mutation has been theorized to be associated with several other mitochondrial diseases, including diabetes mellitus and deafness. 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.

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 AG.

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 3302AG mutation has been found in a patient with the deficiency.

References

References

1. (April 1981). "Sequence and organization of the human mitochondrial genome". Nature.
2. "tRNA / transfer RNA". Learn Science at Scitable.
3. (March 2020). "A Novel Amplification-Refractory Mutation System-PCR Strategy to Screen ''MT-TL1'' Pathogenic Variants in Patient Repositories". Genetic Testing and Molecular Biomarkers.
4. (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.
5. "MT-TH gene".
6. (July 2007). "Genetic, pathogenetic, and phenotypic implications of the mitochondrial A3243G tRNALeu(UUR) mutation". Acta Neurologica Scandinavica.
7. (December 1992). "Diabetes mellitus associated with a pathogenic point mutation in mitochondrial DNA". Lancet.
8. (2012-04-19). "Mitochondrial diabetes in children: seek and you will find it". PLOS ONE.
9. (April 1998). "Novel mitochondrial DNA mutation in tRNA(Lys) (8296A→G) associated with diabetes". Biochemical and Biophysical Research Communications.
10. (October 2004). "Increased risk for cardiorespiratory failure associated with the A3302G mutation in the mitochondrial DNA encoded tRNALeu(UUR) gene". Neuromuscular Disorders.

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