A viable hypomorphic mutation in the mitochondrial ribosome subunit, MRPS-31, exhibits mitochondrial dysfunction in C. elegans.

The mitochondrial ribosome (mitoribosome) translates mitochondrial genome encoded proteins essential for cellular energy production. Given this critical role, defects in the mitoribosome can cause mitochondrial stress and manifest as multisystemic diseases. In a screen for unique activators of the mitochondrial unfolded protein response (UPR ^mt ) in Caenorhabditis elegans , we recovered a strain harboring a missense mutation in the gene encoding mitochondrial ribosome protein S31 ( MRPS-31 )-a component of the mitoribosome small subunit. Herein, we confirm causality of the mrps-31 allele and characterize its induction of UPR ^mt and impact on organismal development, providing a valuable model for further study of the mitoribosome.