mtRF1a is a human mitochondrial translation release factor decoding the major termination codons UAA and UAG

Area of Science:

• Mitochondrial biology
• Molecular genetics
• Cellular processes

Background:

• Human mitochondria possess a unique genome encoding 13 essential polypeptides.
• The intricate molecular mechanisms governing mitochondrial translation, particularly termination, remain largely uncharacterized.
• Existing cellular systems utilize two classes of release factors for translation termination, but mitochondrial equivalents are poorly understood.

Purpose of the Study:

• To identify and characterize factors involved in mitochondrial translation termination.
• To investigate the function of a novel mitochondrial protein, mtRF1a, in this process.
• To elucidate the cellular consequences of impaired mitochondrial translation termination.

Main Methods:

• In vitro assays to assess mtRF1a's release factor activity.
• In vivo studies using HeLa cells to evaluate mtRF1a's function.
• Depletion of mtRF1a in cells to observe phenotypic effects.

Main Results:

• Identification of mtRF1a as a functional mitochondrial release factor.
• Demonstration of mtRF1a's capability to terminate translation at UAA/UAG codons both in vitro and in vivo.
• mtRF1a depletion resulted in compromised cell growth in galactose medium and elevated reactive oxygen species production.

Conclusions:

• mtRF1a is a key protein responsible for translation termination at specific codons in human mitochondria.
• The function of mtRF1a is essential for normal mitochondrial protein synthesis and cellular homeostasis.
• Dysregulation of mtRF1a impacts mitochondrial health, leading to impaired growth and oxidative stress.