Human Mitoribosome Profiling: A Re-engineered Approach Tailored to Study Mitochondrial Translation

To understand the human mitochondrial translation process, tools are required to dissect this system at a global scale. The mechanisms and regulation of translation in mitochondria are different from those in the cytosol, and mitochondrial ribosomes have distinct biochemical properties. In this chapter, we describe in detail the modifications we have made to the ribosome profiling approach to adapt it to the unique characteristics of the human mitochondrial ribosome. This approach maximizes the fraction of mitochondrial ribosomes recovered, providing a snapshot of the mitochondrial translation landscape with minimal bias. We also describe the use of mouse lysate as an internal spike-in control for normalization, allowing quantification of global changes in translation across samples. Finally, we outline the bioinformatic pipelines to process the raw reads and identify mitoribosome A sites in the absence of untranslated regions flanking open reading frames. This method offers a subcodon-resolution time-sensitive global approach to explore the mitochondrial translation process in human cells.