mtCLIC is up-regulated and maintains a mitochondrial membrane potential in mtDNA-depleted L929 cells

SPECIFIC AIMSThe aim was to identify differentially expressed genes in mtDNA-depleted cells that could play a role in two interesting features of these cells such as mitobiogenesis and the generation of a mitochondrial potential. The functional characterization led us to identify mtCLIC, a mitochondrial chloride channel, as a protein that participates in generating a mitochondrial membrane potential in these cells.PRINCIPAL FINDINGS1. Mitochondria are present in mtDNA-depleted L929 cellsWe first confirmed that mitochondria are present in mtDNA-depleted L929 cells. When rhodamine 123 (R123) accumulation is used to measure the mitochondrial membrane potential (Δψm), mitochondria from mtDNA-depleted L929 cells seem to incorporate less probe than the parental cells. These results suggest that mitobiogenesis still occurs in mtDNA-depleted L929 cells even in the absence of functional respiration and mtDNA, but also that mitochondria of these cells retain an electrochemical gradient that generates a potential wh...