Addition of a 29 Residue Carboxyl-terminal Tail Converts a Simple HMG Box-containing Protein into a Transcriptional Activator

Dairaghi, Daniel J.; Shadel, Gerald S.; Clayton, David A.

doi:10.1006/jmbi.1995.9889

Cited by 177 publications

(184 citation statements)

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“…Similar to other HMG box proteins, TFAM is able to bind, wrap, and bend DNA without any obvious sequence specificity 4 . In contrast, the carboxy-terminal tail of TFAM is critical for activation of promoter-specific mtDNA transcription 5 . TFAM's budding yeast homolog (Abf2) consists of two HMG-boxes separated by a short linker, but it has no charged carboxy-terminal tail.…”

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confidence: 98%

TFAM forces mtDNA to make a U-turn

Hällberg

Larsson

2011

Nat Struct Mol Biol

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TFAM forces mtDNA to make a U-turn

Hällberg

Larsson

2011

Nat Struct Mol Biol

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“…In yeast, Abf2p is involved in mtDNA packaging (35,41) and oxidative DNA damage resistance (42) and is missing the C-terminal extension found in the human protein required for its transcriptional stimulatory activity (43,44). This has led to the generalization that the human and yeast basal mitochondrial transcription systems are quite diverged with yeast being a two-component system and human being a three-component system that is dependent on h-mtTFA as an obligate member of the initiation complex (7,22,40,45,46).…”

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Core human mitochondrial transcription apparatus is a regulated two-component system in vitro

Shutt

Lodeiro

Cotney

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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119

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The core human mitochondrial transcription apparatus is currently regarded as an obligate three-component system comprising the bacteriophage T7-related mitochondrial RNA polymerase, the rRNA methyltransferase-related transcription factor, h-mtTFB2, and the high mobility group box transcription/DNA-packaging factor, h-mtTFA/TFAM. Using a faithful recombinant human mitochondrial transcription system from Escherichia coli, we demonstrate that specific initiation from the mtDNA promoters, LSP and HSP1, only requires mitochondrial RNA polymerase and h-mtTFB2 in vitro. When h-mtTFA is added to these basal components, LSP exhibits a much lower threshold for activation and a larger amplitude response than HSP1. In addition, when LSP and HSP1 are together on the same transcription template, h-mtTFA-independent transcription from HSP1 and h-mtTFA-dependent transcription from both promoters is enhanced and a higher concentration of h-mtTFA is required to stimulate HSP1. Promoter competition experiments revealed that, in addition to LSP competing transcription components away from HSP1, additional cis-acting signals are involved in these aspects of promoter regulation. Based on these results, we speculate that the human mitochondrial transcription system may have evolved to differentially regulate transcription initiation and transcription-primed mtDNA replication in response to the amount of h-mtTFA associated with nucleoids, which could begin to explain the heterogeneity of nucleoid structure and activity in vivo. Furthermore, this study sheds new light on the evolution of mitochondrial transcription components by showing that the human system is a regulated two-component system in vitro, and thus more akin to that of budding yeast than thought previously.h-mtTFA/TFAM | mtDNA | nucleoid | POLRMT | h-mtTFB2/TFB2M

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“…Mitochondrial D-loop region; In-vitro transcription; mt RNA polymerase; gel-mobility shift assay; 3D model Both human and mouse mitochondrial (mt) in-vitro reconstituted transcription system and mt lysate were shown to transcribe bidirectionally from D-loop region containing H-strandpromoter/L-strand-promoter (HSP/LSP) of mitochondrial genome .These transcripts ranged between >100bp and >3000bp in both human and mouse [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. The D-loop distal genes were also transcribed in this system [16].…”

Section: Introductionmentioning

confidence: 99%

“…The D-loop distal genes were also transcribed in this system [16]. The nuclear coded RNA polymerase, RNase P and RNase MRP as well as several transcription factors have now been proposed to function in a co-ordinate fashion for the synthesis of the polycistronic RNA and its processing into individual RNA molecules [1][2][3][4][5][6][7][8][9][10][11][12]. The ideal human transcription complex [13] was described to constitute RNA polymerase, transcription factor TFB1M (or TFB2M having weaker activity than TFB2M), LSP/HSP template (1-741bp) and mt general transcription factor TFAM.…”

Section: Introductionmentioning

confidence: 99%

“…Both RNA polymerase and RNase MRP are involved for mt DNA replication from a RNA-D-loop DNA hybrid [1][2][3][4][5][6][7][8][9][10], whereas these two enzymes in addition to RNase P are involved in transcription as well as RNA (mRNA, rRNA and tRNA) processing of human and mouse mt.RNA [1][2][3][4][5][6][7][8][9][10][11][12]23]. RNase MRP cleaves mRNA substrate at an adjacent conserved decamer sequence 5′-CGACCCCUCC-3′ (relative to CSB2 in D-loop), whereas RNase P is involved in 5′ and 3′ end-processing of mt tRNA [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. This conserved decamer sequence 5′-CGACCCCUCC-3′ is also present in MRP RNA [3,4,7,[11][12][13].…”

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3D model of RNA polymerase and bidirectional transcription

Bhattacharya

2007

Biochemical and Biophysical Research Communications

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In the in-vitro mitochondrial (mt) transcription initiation system with mt RNA polymerase fraction and mt lysate, the transcription initiation products were shown to be synthesized bi-directionally from the only H-strand-promoter (HSP)/L-strand-promoter region (LSP) of the mitochondrial Dloop genome segment. These transcription products ranged between >100bp and >800bp with the purified mitochondrial RNA polymerase fraction, but were larger (>2030bp-4000bp) in size with the mitochondrial lysate in both human and mouse [references 1-20]. In this brief report, an invitro reconstituted mitochondrial transcription system purified by affinity chromatography (heparinsepharose) from mouse hypotetraploid letter Ehrlich ascites tumor cell mitochondria was shown to initiate transcription bidirectionally from the mitochondrial D-loop region (HSP/LSP), as evidenced by in-vitro generated transcription products. The in-vitro generated transcription products were separated by sequencing gel. But this in-vitro reconstituted transcription system was not studied beyond the D-loop region. A 3D model of the enzyme RNA polymerase was docked with both ATP and CTP. KeywordsMitochondrial D-loop region; In-vitro transcription; mt RNA polymerase; gel-mobility shift assay; 3D model Both human and mouse mitochondrial (mt) in-vitro reconstituted transcription system and mt lysate were shown to transcribe bidirectionally from D-loop region containing H-strandpromoter/L-strand-promoter (HSP/LSP) of mitochondrial genome .These transcripts ranged between >100bp and >3000bp in both human and mouse [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. The D-loop distal genes were also transcribed in this system [16]. The nuclear coded RNA polymerase, RNase P and RNase MRP as well as several transcription factors have now been proposed to function in a co-ordinate fashion for the synthesis of the polycistronic RNA and its processing into individual RNA molecules [1][2][3][4][5][6][7][8][9][10][11][12]. The ideal human transcription complex [13] was described to constitute RNA polymerase, transcription factor TFB1M (or TFB2M having weaker activity than TFB2M), LSP/HSP template (1-741bp) and mt general transcription factor TFAM. The mouse homologs (or orthologs) mTfb1m and mTfb2m were identified [13]. The transcription termination was reported to occur by 34kd mt-TERM/mtTERF DNA binding protein [14,15], although 24kd Tf1 transcription factor, 48kd TAS-A protein (which binds to termination associated sequence of mt D-loop region) as well as other putative binding proteins (TAS-B, -C, -D, -E, -F, -G; A/B and F/G which bind to partially overlapping sites) in the mt D-loop segment were reported [15,16]. Two-to-three putative mitochondrial transcription termination 1 Corresponding author: Pradip Bhattacharya, Room Nos. 121, School of Life Sciences, Jawaharlal Nehru University, New Delhi-110067, India. Fax: 91-11-26165886; Tel: 91-11-26704529, Email address: ronaldraegon@yahoo.com Publisher's Disclaimer: This is a PDF file o...

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Addition of a 29 Residue Carboxyl-terminal Tail Converts a Simple HMG Box-containing Protein into a Transcriptional Activator

Cited by 177 publications

References 0 publications

TFAM forces mtDNA to make a U-turn

TFAM forces mtDNA to make a U-turn

Core human mitochondrial transcription apparatus is a regulated two-component system in vitro

3D model of RNA polymerase and bidirectional transcription

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