Figure 3.

Regulatory role of TFAM in DNA transactions. Model of how TFAM levels and DNA compaction (upper panel) regulate replication and transcription in mitochondria (lower panel). Increases in TFAM levels (green) result in more DNA (grey duplex ring) compaction, which ultimately results in a fully compacted nucleoid. Mitochondria with low TFAM levels and, thus, less compacted mtDNA are permissive environments for replication (black arrow) and transcription (orange line). Increases in mitochondrial TFAM levels lead to more fully-compacted nucleoids that are refractory to replication and transcription, and fewer actively replicating/transcribing mtDNA molecules.