The manner in which DNA is packaged with TFAM has an impact on transcription activation and inhibition

For successful mitochondrial transgene expression, an optimal packaging exogenous DNA is an important issue. We report herein on the effects of DNA packaged with mitochondrial transcription factor A (TFAM), which packages mitochondrial DNA (mtDNA), on the transcription process. Our initial findings indicated that the transcription of the TFAM/DNA complex was activated, when the complex was formed at an optimal ratio. We also found that TFAM has a significant advantage over protamine, a nuclear DNA packaging protein, from the viewpoint of transcription efficiency. This result indicates that TFAM can be useful packaging protein for exogenous DNA to achieve mitochondrial transgene expression.