TY - JOUR
T1 - In Vitro-Reconstituted Nucleoids Can Block Mitochondrial DNA Replication and Transcription
AU - Farge, G.A.
AU - Mehmedovic, M.
AU - Baclayon, M.
AU - Wildenberg, S.M.J.L.
AU - Roos, W.H.
AU - Gustafsson, C. M.
AU - Wuite, G.J.L.
AU - Falkenberg, M.
PY - 2014
Y1 - 2014
N2 - The mechanisms regulating the number of active copies of mtDNA are still unclear. A mammalian cell typically contains 1,000-10,000 copies of mtDNA, which are packaged into nucleoprotein complexes termed nucleoids. The main protein component of these structures is mitochondrial transcription factor A (TFAM). Here, we reconstitute nucleoid-like particles in vitro and demonstrate that small changes in TFAM levels dramatically impact the fraction of DNA molecules available for transcription and DNA replication. Compaction by TFAM is highly cooperative, andat physiological ratios of TFAM to DNA, there are large variations in compaction, from fully compacted nucleoids to naked DNA. In compacted nucleoids, TFAM forms stable protein filaments on DNA that block melting and prevent progression of the replication and transcription machineries. Based on our observations, we suggest that small variations in the TFAM-to-mtDNA ratio may be used to regulate mitochondrial gene transcription and DNA replication. © 2014 The Authors.
AB - The mechanisms regulating the number of active copies of mtDNA are still unclear. A mammalian cell typically contains 1,000-10,000 copies of mtDNA, which are packaged into nucleoprotein complexes termed nucleoids. The main protein component of these structures is mitochondrial transcription factor A (TFAM). Here, we reconstitute nucleoid-like particles in vitro and demonstrate that small changes in TFAM levels dramatically impact the fraction of DNA molecules available for transcription and DNA replication. Compaction by TFAM is highly cooperative, andat physiological ratios of TFAM to DNA, there are large variations in compaction, from fully compacted nucleoids to naked DNA. In compacted nucleoids, TFAM forms stable protein filaments on DNA that block melting and prevent progression of the replication and transcription machineries. Based on our observations, we suggest that small variations in the TFAM-to-mtDNA ratio may be used to regulate mitochondrial gene transcription and DNA replication. © 2014 The Authors.
U2 - 10.1016/j.celrep.2014.05.046
DO - 10.1016/j.celrep.2014.05.046
M3 - Article
SN - 2211-1247
VL - 2014
SP - 66
EP - 74
JO - Cell Reports
JF - Cell Reports
IS - 8
ER -