In organello footprint analysis of human mitochondrial DNA: human mitochondrial transcription factor A interactions at the origin of replication

1994 ◽  
Vol 14 (12) ◽  
pp. 7717-7730
Author(s):  
S C Ghivizzani ◽  
C S Madsen ◽  
M R Nelen ◽  
C V Ammini ◽  
W W Hauswirth
Keyword(s):  
Transcription Factor ◽  
Mitochondrial Dna ◽  
Dna Interaction ◽  
Mitochondrial Transcription ◽  
Mitochondrial Transcription Factor ◽  
In Organello ◽  
D Loop ◽  
Footprint Analysis ◽  
Mitochondrial Transcription Factor A

Using in organello footprint analysis, we demonstrate that within human placental mitochondria there is a high level of protein-DNA binding at regularly phased intervals throughout a 500-bp region encompassing the D-loop DNA origins and two promoter regions. Comparison with in vitro DNase I protection studies indicates that this protein-DNA interaction is due to non-sequence-specific binding by human mitochondrial transcription factor A (h-mtTFA). Since h-mtTFA can bend and wrap DNA, like its yeast counterpart ABF2, a primary function of h-mtTFA appears to be specific packaging of the mitochondrial DNA control region in vivo. Intervals of protein binding coincide with the spacing of the RNA start sites and prominent D-loop DNA 5' ends, suggesting a role for phased h-mtTFA binding in defining transcription and H-strand DNA replication origins. Significant protein-DNA interaction was also observed within the human homolog of conserved sequence block 1, both in organello and in vitro, using purified h-mtTFA.

scholarly journals In organello footprint analysis of human mitochondrial DNA: human mitochondrial transcription factor A interactions at the origin of replication.

1994 ◽  
Vol 14 (12) ◽  
pp. 7717-7730 ◽  
Author(s):  
S C Ghivizzani ◽  
C S Madsen ◽  
M R Nelen ◽  
C V Ammini ◽  
W W Hauswirth
Keyword(s):  
Transcription Factor ◽  
Mitochondrial Dna ◽  
Dna Interaction ◽  
Mitochondrial Transcription ◽  
Mitochondrial Transcription Factor ◽  
In Organello ◽  
D Loop ◽  
Footprint Analysis ◽  
Mitochondrial Transcription Factor A

Using in organello footprint analysis, we demonstrate that within human placental mitochondria there is a high level of protein-DNA binding at regularly phased intervals throughout a 500-bp region encompassing the D-loop DNA origins and two promoter regions. Comparison with in vitro DNase I protection studies indicates that this protein-DNA interaction is due to non-sequence-specific binding by human mitochondrial transcription factor A (h-mtTFA). Since h-mtTFA can bend and wrap DNA, like its yeast counterpart ABF2, a primary function of h-mtTFA appears to be specific packaging of the mitochondrial DNA control region in vivo. Intervals of protein binding coincide with the spacing of the RNA start sites and prominent D-loop DNA 5' ends, suggesting a role for phased h-mtTFA binding in defining transcription and H-strand DNA replication origins. Significant protein-DNA interaction was also observed within the human homolog of conserved sequence block 1, both in organello and in vitro, using purified h-mtTFA.

A human mitochondrial transcriptional activator can functionally replace a yeast mitochondrial HMG-box protein both in vivo and in vitro

1993 ◽  
Vol 13 (3) ◽  
pp. 1951-1961
Author(s):  
M A Parisi ◽  
B Xu ◽  
D A Clayton
Keyword(s):  
Transcription Factor ◽  
Mitochondrial Dna ◽  
Nuclear Gene ◽  
Transcriptional Activator ◽  
Yeast Mitochondria ◽  
Yeast Protein ◽  
Mitochondrial Transcription ◽  
Mitochondrial Transcription Factor ◽  
Mitochondrial Transcription Factor A

Human mitochondrial transcription factor A is a 25-kDa protein that binds immediately upstream of the two major mitochondrial promoters, thereby leading to correct and efficient initiation of transcription. Although the nature of yeast mitochondrial promoters is significantly different from that of human promoters, a potential functional homolog of the human transcriptional activator protein has been previously identified in yeast mitochondria. The importance of the yeast protein in yeast mitochondrial DNA function has been shown by inactivation of its nuclear gene (ABF2) in Saccharomyces cerevisiae cells resulting in loss of mitochondrial DNA. We report here that the nuclear gene for human mitochondrial transcription factor A can be stably expressed in yeast cells devoid of the yeast homolog protein. The human protein is imported efficiently into yeast mitochondria, is processed correctly, and rescues the loss-of-mitochondrial DNA phenotype in a yeast abf2 strain, thus functionally substituting for the yeast protein. Both human and yeast proteins affect yeast mitochondrial transcription initiation in vitro, suggesting that the two proteins may have a common role in this fundamental process.

scholarly journals A human mitochondrial transcriptional activator can functionally replace a yeast mitochondrial HMG-box protein both in vivo and in vitro.

1993 ◽  
Vol 13 (3) ◽  
pp. 1951-1961 ◽  
Author(s):  
M A Parisi ◽  
B Xu ◽  
D A Clayton
Keyword(s):  
Transcription Factor ◽  
Mitochondrial Dna ◽  
Nuclear Gene ◽  
Transcriptional Activator ◽  
Yeast Mitochondria ◽  
Yeast Protein ◽  
Mitochondrial Transcription ◽  
Mitochondrial Transcription Factor ◽  
Mitochondrial Transcription Factor A

Human mitochondrial transcription factor A is a 25-kDa protein that binds immediately upstream of the two major mitochondrial promoters, thereby leading to correct and efficient initiation of transcription. Although the nature of yeast mitochondrial promoters is significantly different from that of human promoters, a potential functional homolog of the human transcriptional activator protein has been previously identified in yeast mitochondria. The importance of the yeast protein in yeast mitochondrial DNA function has been shown by inactivation of its nuclear gene (ABF2) in Saccharomyces cerevisiae cells resulting in loss of mitochondrial DNA. We report here that the nuclear gene for human mitochondrial transcription factor A can be stably expressed in yeast cells devoid of the yeast homolog protein. The human protein is imported efficiently into yeast mitochondria, is processed correctly, and rescues the loss-of-mitochondrial DNA phenotype in a yeast abf2 strain, thus functionally substituting for the yeast protein. Both human and yeast proteins affect yeast mitochondrial transcription initiation in vitro, suggesting that the two proteins may have a common role in this fundamental process.

scholarly journals Architectural Role of Mitochondrial Transcription Factor A in Maintenance of Human Mitochondrial DNA

2004 ◽  
Vol 24 (22) ◽  
pp. 9823-9834 ◽  
Author(s):  
Tomotake Kanki ◽  
Kippei Ohgaki ◽  
Martina Gaspari ◽  
Claes M. Gustafsson ◽  
Atsushi Fukuoh ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Mitochondrial Dna ◽  
Rna Interference ◽  
Normal Level ◽  
Hela Cells ◽  
Mitochondrial Transcription ◽  
Mitochondrial Transcription Factor ◽  
In Organello ◽  
Mitochondrial Transcription Factor A

ABSTRACT Mitochondrial transcription factor A (TFAM), a transcription factor for mitochondrial DNA (mtDNA) that also possesses the property of nonspecific DNA binding, is essential for maintenance of mtDNA. To clarify the role of TFAM, we repressed the expression of endogenous TFAM in HeLa cells by RNA interference. The amount of TFAM decreased maximally to about 15% of the normal level at day 3 after RNA interference and then recovered gradually. The amount of mtDNA changed closely in parallel with the daily change in TFAM while in organello transcription of mtDNA at day 3 was maintained at about 50% of the normal level. TFAM lacking its C-terminal 25 amino acids (TFAM-ΔC) marginally activated transcription in vitro. When TFAM-ΔC was expressed at levels comparable to those of endogenous TFAM in HeLa cells, mtDNA increased twofold, suggesting that TFAM-ΔC is as competent in maintaining mtDNA as endogenous TFAM under these conditions. The in organello transcription of TFAM-ΔC-expressing cells was no more than that in the control. Thus, the mtDNA amount is finely correlated with the amount of TFAM but not with the transcription level. We discuss an architectural role for TFAM in the maintenance of mtDNA in addition to its role in transcription activation.

141 Mitochondrial transcription factor a mitochondrial DNA repair

Mitochondrion ◽  
2010 ◽  
Vol 10 (2) ◽  
pp. 240
Author(s):  
Deborah L. Croteau ◽  
Anne-Cécile V. Bayne ◽  
Chandrika Canugovi ◽  
Scott Maynard ◽  
Nadja de Souza-Pinto ◽  
...  
Keyword(s):  
Dna Repair ◽  
Transcription Factor ◽  
Mitochondrial Dna ◽  
Mitochondrial Transcription ◽  
Mitochondrial Transcription Factor ◽  
Mitochondrial Dna Repair ◽  
Mitochondrial Transcription Factor A

scholarly journals Mitochondrial Transcription Factor A Regulates Mycobacterium bovis–Induced IFN-β Production by Modulating Mitochondrial DNA Replication in Macrophages

2019 ◽  
Author(s):  
Yinjuan Song ◽  
Tariq Hussain ◽  
Jie Wang ◽  
Yi Liao ◽  
Ruichao Yue ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Mitochondrial Dna ◽  
Mycobacterium Bovis ◽  
Intracellular Survival ◽  
Vital Role ◽  
Mitochondrial Transcription ◽  
Host Immune Responses ◽  
Mitochondrial Transcription Factor ◽  
Copy Numbers ◽  
Mitochondrial Transcription Factor A

Abstract Background Mycobacterium bovis persistently survives in macrophages by developing multiple strategies to evade host immune responses, and the early induction of interferon-β (IFN-β) is one of these critical strategies. The mitochondrial transcription factor A (TFAM) plays a vital role in mitochondrial DNA (mtDNA) metabolism and has been suggested to influence IFN-β production in response to viral infection. However, its role in the production of IFN-β by M. bovis has not been elucidated. Methods In the current study, we investigated the role of TFAM in the production of IFN-β in M. bovis–infected macrophages. Results We found that knockdown of TFAM expression significantly reduced M. bovis–induced IFN-β production, mtDNA copy numbers and cytosolic mtDNA were increased in murine macrophages with M. bovis infection, cytosolic mtDNA contributed to IFN-β production, and TFAM was required for the increase in mtDNA copy numbers induced by M. bovis. We also observed that TFAM affected the intracellular survival of M. bovis. Conclusions Our results suggest that TFAM plays an essential role in M. bovis–induced IFN-β production by regulating mtDNA copy numbers. This might be a new strategy adopted by M. bovis for its intracellular survival.

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