Why the MOTS-c reading frame gives a different peptide depending on where it is translated

Published 26 October 2026 · REVIVE LAB UAE Research Desk · 5 min read
The 51-nucleotide open reading frame for MOTS-c lies within MT-RNR1, the gene for the mitochondrial 12S ribosomal RNA. Mitochondria use a genetic code that differs from the standard one at several codons. Translated with the standard code, the frame yields the 16-residue peptide; translated with the mitochondrial code, an early stop codon truncates it. Lee and colleagues inferred in 2015 that the transcript is exported and translated by cytoplasmic ribosomes, which is how a mitochondrial gene produces a peptide the mitochondrion itself could not make in full.

The two codes

In mitochondria, UGA codes for tryptophan rather than stop, AUA for methionine rather than isoleucine, and AGA and AGG are stops rather than arginine. A sequence read by both machineries can therefore give different products. For the MOTS-c frame the difference is decisive: one code gives a full peptide, the other a fragment.

This is a general feature of small open reading frames in mitochondrial DNA, several of which encode mitochondrial-derived peptides.

What the 2015 paper inferred

The authors detected a polyadenylated transcript containing the frame in the cytoplasm, and the peptide itself by antibody in cells and tissue. Mitochondrial ribosomes could not have produced the detected sequence. The conclusion that translation is cytoplasmic rests on this reasoning and on the detection data, and later work has not overturned it.

How the transcript leaves the mitochondrion is not fully resolved.

Why it matters

Because it places MOTS-c in an unusual category: a peptide encoded by one genome and made by the machinery of the other. The page on the mitochondrial-derived peptide family sets out the others.

MOTS-c is supplied by REVIVE LAB UAE for laboratory research use only, with identity by mass spectrometry and purity by HPLC for the batch. It is not for human or veterinary use, and no dosing, administration or protocol guidance is provided.

What it costs

FormatStrengthPriceAvailability
MOTS-c Pack40 mgAED 950In stock

Delivery is AED 40 flat and free on orders over AED 700. Payment is cash on delivery anywhere in the UAE, or USDT (TRC20) in advance, which takes 5% off the order total.

Frequently asked

The two codes?

In mitochondria, UGA codes for tryptophan rather than stop, AUA for methionine rather than isoleucine, and AGA and AGG are stops rather than arginine. A sequence read by both machineries can therefore give different products. For the MOTS-c frame the difference is decisive: one code gives a full peptide, the other a fragment.

Does REVIVE LAB UAE provide dosing guidance?

No. REVIVE LAB UAE supplies research materials and provides no dosing, administration or protocol guidance of any kind. Every product is sold for laboratory research use only and is not for human or veterinary consumption.

How fast is delivery in the UAE?

Stock is held in Dubai. An order confirmed before 4 PM Dubai time is dispatched the same working day, reaching Dubai and Abu Dhabi the same day and the remaining emirates within 24 hours. Delivery is AED 40 flat and free over AED 700.

MOTS-c Pack — in stock, dispatched from Dubai
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Related reading

Supplied for laboratory research use only. Not for human or veterinary consumption. REVIVE LAB UAE provides no dosing, administration or protocol guidance.