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Biology subjects

Madern, M. F.

Publications and source records attributed to Madern, M. F..

2 recordsLinked to original sources

Ribosome cooperativity promotes fast and efficient translation

The genetic information stored in mRNA is decoded by ribosomes during mRNA translation. mRNAs are typically translated by multiple ribosomes simultaneously, but it is unclear if different ribosomes translating the same mRNA functionally interact with each other. Here, we combine single-ribosome imaging and simulations to compare translation dynamics of individual ribosomes in either monosomes or polysomes to determine how ribosomes interact during translation. We find that ribosomes frequently undergo transient collisions, but that transient collisions, unlike persistent collisions, escape detection by cellular quality control pathways. Instead, our results indicate that transient ribosome collisions promote productive translation by suppressing ribosome pausing when ribosomes encounter problems, a process we term ribosome cooperativity. Ribosome cooperativity also suppresses ribosome recycling on problematic sequences, likely by reducing pause duration, thus stimulating processive translation. Together, our results show that ribosomes cooperate during translation to ensure fast and efficient translation.

molecular biology↗

Dissecting translation elongation dynamics through ultra-long tracking of single ribosomes

mRNA translation by ribosomes is a highly dynamic and heterogeneous process. However, current approaches cannot readily resolve individual ribosomes during translation, limiting our understanding of translation dynamics. Here, we develop an imaging approach based on Stopless-ORF circular RNAs (socRNAs) to monitor individual translating ribosomes for hours. Using the socRNA imaging technology we obtained accurate measurements of ribosome pausing on various problematic RNA sequences or induced by ribosome-targeting drugs. In addition, we identified a novel translation factor involved in translation elongation, and revealed that translocation rates of ribosomes vary, indicative of intracellular ribosomal heterogeneity. Finally, socRNAs allow very sensitive measurements of translation elongation fidelity, revealing widespread frameshifting during translation. In summary, our single-ribosome imaging approach provides a detailed view of ribosome translocation kinetics and a powerful new tool to study the translation elongation phase.

molecular biology↗