MT-TW encodes mitochondrial tRNA-Trp, 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 tryptophan by the corresponding mitochondrial aminoacyl-tRNA synthetase and, in the mitochondrial matrix, acts as the adaptor that reads the tryptophan codons UGA and UGG (UGR) of the 13 mtDNA-encoded mRNAs on the mitoribosome, delivering tryptophan to the growing polypeptide. In the vertebrate mitochondrial genetic code UGA specifies tryptophan rather than termination, so this tRNA reads both UGG and UGA. Pathogenic variants in MT-TW, 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:0030533 triplet codon-amino acid adaptor activity | TAS | NEW | Summary: No GOA annotation exists for MT-TW (RNAcentral/Rfam2GO supplies GO:0030533 for some but not all mt-tRNA sequences). Proposed to record the canonical tRNA adaptor function. Reason: MT-TW is one of the 22 mtDNA-encoded tRNAs used by the mitochondrial translation machinery; the codon-anticodon adaptor function is carried out by the tRNA itself. The same term is assigned by Rfam2GO to sister mt-tRNAs (e.g. MT-TQ, MT-TH, MT-TS1). 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:0032543 mitochondrial translation | TAS | NEW | Summary: Proposed process annotation for the mitochondrial tRNA. Reason: The tRNA directly performs the decoding step of mitochondrial translation (it is not merely required for it), so involved_in mitochondrial translation is appropriate; this is the specific child of translation that sister mt-tRNAs receive via the MODIFY of their IEA translation annotation. 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. |
Loading supporting content…
Download this section (compressed HTML)Q: Should GO annotate all 22 mtDNA-encoded tRNAs, including MT-TW, 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
Loading supporting content…
Download this section (compressed HTML)Loading supporting content…
Download this section (compressed HTML)