Rhomboid-7 over-expression results in Opa1-like processing and malfunctioning mitochondria

Area of Science:

• Molecular Biology
• Neuroscience
• Genetics

Background:

• Rhomboid-7 (rho-7) is a mitochondrial protease.
• Loss-of-function mutations in rho-7 lead to semi-lethality, neurological disorders, and reduced lifespan in surviving Drosophila.
• The precise role of rho-7 in mitochondrial function and its associated pathologies remains unclear.

Purpose of the Study:

• To investigate the effects of rho-7 expression levels on Drosophila development, lifespan, and neurological function.
• To elucidate the molecular mechanisms underlying rho-7-associated mitochondrial dysfunction and apoptosis.
• To identify potential interacting partners of rho-7 in cellular pathways.

Main Methods:

• Generated transgenic Drosophila with varying expression levels of rho-7 (rescue and overexpression).
• Assessed viability, lifespan, locomotion, and neurological phenotypes.
• Quantified ATP levels, cytochrome c oxidase subunit II mRNA, mitochondrial morphology, and apoptotic index.
• Investigated the genetic interaction between rho-7 and Opa1-like.

Main Results:

• CNS-specific or general rho-7 expression rescued rho-7 loss-of-function lethality.
• rho-7 overexpression caused semi-lethality, shortened lifespan, larval locomotion defects, reduced ATP levels, mitochondrial abnormalities, and increased apoptosis.
• rho-7 overexpression correlated with elevated Opa1-like levels, and Opa1-like heterozygosity suppressed most rho-7 overexpression phenotypes.

Conclusions:

• rho-7 plays a critical role in maintaining mitochondrial function and preventing apoptosis in Drosophila.
• Dysregulation of rho-7 impacts mitochondrial dynamics, energy production, and neuronal health.
• rho-7 and Opa1-like likely function in a common pathway influencing mitochondrial homeostasis and programmed cell death.