Study reveals widespread stop codon readthrough as major regulatory mechanism in fruit flies
Researchers systematically characterized stop codon readthrough (SCR) in Drosophila melanogaster, identifying approximately 1,400 genes where ribosomes continue translating past the stop codon. Using ribosome profiling, comparative genomics, proteomics, and functional screening, they found conserved regulatory elements that can also function in mammalian cells. The findings reframe SCR not as a rare error but as a pervasive regulatory mechanism with implications for protein output and proteome diversity.
A new study published on bioRxiv presents a comprehensive atlas of stop codon readthrough (SCR) in Drosophila melanogaster, identifying roughly 1,400 genes subject to this phenomenon, in which ribosomes bypass the stop codon and continue translation. The researchers integrated multiple high-throughput approaches—ribosome profiling, comparative genomics, proteomics, and functional screening—to characterize both constitutive and tissue-restricted modes of SCR. They identified conserved cis-regulatory elements sufficient to stimulate SCR and showed that many of these elements retain functionality when tested in mammalian cells. Notably, the key difference between insect and mammalian SCR was not the efficiency of translation termination per se, but rather the greater responsiveness of insect cells to SCR-promoting regulatory elements. An unexpected finding was that SCR correlated with increased overall protein output, suggesting its biological role extends beyond simply diversifying the proteome. The work provides a new conceptual framework and a publicly accessible resource—the Drosophila Stop Codon Readthrough Atlas—for future investigation of this regulatory mechanism.
What's missing
The study does not fully resolve the molecular mechanisms by which insect cells are more responsive to SCR-promoting elements than mammalian cells, nor does it establish the functional consequences of SCR for most of the ~1,400 identified genes. The extent to which these findings generalize beyond Drosophila melanogaster to other insect species remains an open question.
What different sources said
- bioRxivCenter
Regulatory landscape of widespread stop codon readthrough in Drosophila
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