New DNA-binding activity of rat mitochondrial transcription termination factor (mTERF).

The molecular mechanisms involved in the regulation of the balance between rRNA and mRNA in mitochondria are poorly understood. The mitochondrial transcription termination factor (mTERF) was highlighted as a potential transcription-control point. In this study, rat mTERF has been expressed in vitro and in Escherichia coli. The mature protein, in addition to the expected specific DNA-binding capacity for the sequence required for termination, has a new DNA-binding activity, and is able to bind to rat mitochondrial promoter region. This finding suggests communication between transcription initiation and termination regions. However, the results of a competition experiment argue against the formation of a complex between rat mTERF and the termination probe and promoter probe simultaneously, although it remains to be investigated whether another factor(s) might be involved in this interaction. In addition, recombinant human mTERF is also able to bind to human mitochondrial promoter region.