YBEY is an essential biogenesis factor for mitochondrial ribosomes

Area of Science:

• Cell Biology
• Molecular Biology
• Genetics

Background:

• Ribosome biogenesis is essential for protein synthesis and involves conserved trans-acting factors.
• The endoribonuclease YbeY (YBEY) is implicated in bacterial 16S rRNA processing and eukaryotic mitochondrial/chloroplast functions.

Purpose of the Study:

• To investigate the role of human YBEY in mitochondrial function and ribosome biogenesis.
• To elucidate the specific mechanism by which YBEY influences mitochondrial health.

Main Methods:

• Gene deletion studies in human cells to create YBEY knockout lines.
• Analysis of mitochondrial morphology, respiratory function, and ribosomal components (12S rRNA, small ribosomal subunit proteins).
• Biochemical assays to determine protein interactions, specifically between YBEY and mitoribosomal protein uS11m.

Main Results:

• YBEY deletion led to severe respiratory deficiency and morphologically abnormal mitochondria.
• YBEY knockout cells exhibited reduced 12S rRNA stability and a deficiency in small ribosomal subunit proteins.
• A specific interaction was identified between YBEY and the mitoribosomal protein uS11m, suggesting a role in late-stage assembly.

Conclusions:

• Human YBEY is essential for mitochondrial ribosome biogenesis, particularly for the proper incorporation of uS11m during late assembly stages.
• Dysfunction of YBEY impairs mitochondrial translation, leading to cellular respiratory defects.
• YBEY may act as a checkpoint in the final stages of mitoribosome assembly before translation initiation.