Comprehensive application of an mtDsRed2-Tg mouse strain for mitochondrial imaging.

Mitochondria are essential for many cellular functions such as oxidative phosphorylation and calcium homeostasis; consequently, mitochondrial dysfunction could cause many diseases, including neurological disorders. Recently, mitochondrial dynamics, such as fusion, fission, and transportation, have been visualized in living cells by using time-lapse imaging systems. The changes in mitochondrial morphology could be an indicator for estimating the activity of mitochondrial biological function. Here, we report a transgenic mouse strain, mtDsRed2-Tg, which expresses a red fluorescent protein, DsRed2, exclusively in mitochondria. Mitochondrial morphology could be clearly observed in various tissues of this strain under confocal microscope. Recently, many transgenic mouse strains in which enhanced green fluorescent protein (EGFP)-tagged proteins of interest are expressed have been established for physiological analysis in vivo. After mating these strains with mtDsRed2-Tg mice, red-colored mitochondria and green-colored proteins were detected simultaneously using fluorescent imaging systems, and the interactions between mitochondria and those proteins could be morphologically analyzed in cells and tissues of the F(1) hybrids. Thus, mtDsRed2-Tg mice can be a powerful tool for bioimaging studies on mitochondrial functions.