MT-TH encodes mitochondrial tRNA-His, one of the 22 transfer RNAs encoded by mitochondrial DNA. After excision from the polycistronic mtDNA transcript and post-transcriptional maturation, it is charged with histidine by the corresponding mitochondrial aminoacyl-tRNA synthetase and, in the mitochondrial matrix, acts as the adaptor that reads the histidine codons CAU and CAC (CAY) of the 13 mtDNA-encoded mRNAs on the mitoribosome, delivering histidine to the growing polypeptide. Pathogenic variants in MT-TH, like those in other mt-tRNA genes, impair mitochondrial translation and oxidative phosphorylation and cause maternally inherited mitochondrial disease.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0006412 translation | IEA GO_REF:0000108 | MODIFY | Summary: Electronic inference from the Rfam-derived adaptor MF (GO:0030533 part_of translation). Correct in kind, but this mtDNA-encoded tRNA functions only in mitochondrial translation. Reason: The tRNA participates directly in translation (it performs the codon-reading adaptor step), so the process is right; the specific process for an mtDNA-encoded tRNA read on the mitoribosome is mitochondrial translation (GO:0032543, is_a translation). Proposed replacements: mitochondrial translation Supporting Evidence: PMID:21910628 These mRNAs are translated by the mitochondrial protein synthesis machinery, which uses the 22 species of mitochondrial tRNAs (mt tRNAs) encoded by mtDNA. |
| GO:0030533 triplet codon-amino acid adaptor activity | IEA GO_REF:0000115 | ACCEPT | Summary: Rfam2GO (RF00005 tRNA family) assignment of the canonical tRNA molecular function. Reason: Codon-anticodon adaptor activity is the core molecular function of a tRNA and is carried out by the tRNA itself; MT-TH is the mitochondrial tRNA-His that reads the histidine codons of mtDNA-encoded mRNAs. Supporting Evidence: PMID:21910628 These mRNAs are translated by the mitochondrial protein synthesis machinery, which uses the 22 species of mitochondrial tRNAs (mt tRNAs) encoded by mtDNA. |
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Download this section (compressed HTML)Q: Should GO annotate all 22 mtDNA-encoded tRNAs, including MT-TH, uniformly to triplet codon-amino acid adaptor activity and mitochondrial translation, rather than relying on Rfam2GO coverage that varies between mt-tRNA sequences?
Suggested experts: GO RNA annotation curators
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