Nuclear factor I enhances adenovirus DNA replication by increasing the stability of a preinitiation complex.

Mul, Y M; Vliet, Peter C. van der

doi:10.1002/j.1460-2075.1992.tb05108.x

Cited by 73 publications

(77 citation statements)

References 64 publications

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“…The nuclear matrix is considered to be a scaffold to which the replication proteins are recruited. The nuclear matrix affinities of NF1 and OTF may also contribute to the increase in the stability of the PIC (39). The GR has also been shown to interact with the nuclear matrix (18,32).…”

Section: Discussionmentioning

confidence: 99%

Nuclear Factor 1 Is Required for Both Hormone-Dependent Chromatin Remodeling and Transcriptional Activation of the Mouse Mammary Tumor Virus Promoter

Hebbar

Archer

2003

Molecular and Cellular Biology

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The mouse mammary tumor virus (MMTV) promoter has been used as a model to study how the glucocorticoid receptor (GR) remodels chromatin to allow other transcription factors to bind and activate transcription. To dissect the precise role of nuclear factor 1 (NF1) in chromatin remodeling and transcriptional activation, we used linker-scanning mutants of transcription factor binding sites on the MMTV promoter. We compared the NF1 mutant MMTV promoter in the context of transiently transfected templates (transient transfection) and templates organized as chromatin (stable transfection) to understand the effect of chromatin on factor binding and transcription. We show that on a transiently transfected template, mutation in the NF1 binding site reduces both basal and hormone-dependent transcription. This suggests that NF1 is required for transcription in the absence of organized chromatin. We also found that binding of NF1 on a transiently transfected template is independent of mutation in hormone response elements or the octamer transcription factor (OTF) binding site. In contrast, the binding of OTF proteins to a transiently transfected template was found to be dependent on the binding of NF1, which may imply that NF1 has a stabilizing effect on OTF binding. On a chromatin template, mutation in the NF1 binding site does not affect the positioning of nucleosomes on the promoter. We also show that in the absence of NF1 binding, GR-mediated chromatin remodeling of nucleosome B is reduced and hormone-dependent activation of transcription is abolished. Further, we demonstrate that NF1 is required for both the association of BRG1 chromatin remodeling complex and the GR on the promoter in vivo. These results suggest the novel possibility that NF1 may participate in chromatin remodeling activities in addition to directly enhancing transcription and that in the absence of its binding site the GR is unable to effectively bind the promoter and recruit the remodeling complex.The eukaryotic genome is structurally organized into nucleosomes to form chromatin (55). During gene expression, there is a need for distinct multiprotein complexes to modulate higher-order chromatin structure (20, 30), modify nucleosomal structures (45), and bind to regulatory sequences to initiate transcription. Sequence-specific DNA binding factors represent a large group of regulatory proteins that bind to the upstream regulatory regions of promoters and enhancer regions to mediate transcription (26). The organization of DNA in chromatin influences the ability of these factors to interact with their cognate recognition sites (51, 54). Steroid receptors are a class of transcription factors that can interact with the repressive chromatin structure and remodel the chromatin to allow other transcription factors to bind (29). The potential role of steroid receptors in chromatin remodeling and transcription is exemplified by the glucocorticoid receptor (GR)-mediated transactivation of the mouse mammary tumor virus (MMTV) promoter (17).The MMTV promoter is orga...

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Section: Discussionmentioning

confidence: 99%

Nuclear Factor 1 Is Required for Both Hormone-Dependent Chromatin Remodeling and Transcriptional Activation of the Mouse Mammary Tumor Virus Promoter

Hebbar

Archer

2003

Molecular and Cellular Biology

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“…Three of these proteins are of viral origin: precursor terminal protein (pTP), polymerase (Pol), and DBP. pTP and Pol form a tight heterodimer in solution and bind to the origin located at the molecular ends of adenovirus DNA (23,28,31). Two other proteins, nuclear factor I (NFI) and Oct-1, originate from the host cell.…”

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confidence: 99%

Adenovirus Type 5 DNA Binding Protein Stimulates Binding of DNA Polymerase to the Replication Origin

Breukelen

Brenkman

Holthuizen

et al. 2003

J Virol

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The adenovirus (Ad) DNA-binding protein (DBP) is essential for the elongation phase of Ad DNA replication by unwinding the template in an ATP-independent fashion, employing its capacity to form multimers. DBP also enhances the rate of initiation, with the highest levels obtained at low concentrations of Ad DNA polymerase (Pol). Here, we show that stimulation of initiation depends on the template conformation. Maximal stimulation, up to 15-fold, is observed on double-stranded or viral TP-containing origins. The stimulation is reduced on partially single-stranded origins and DBP does not enhance initiation any more once the origin is completely unwound. This suggests a role for DBP in origin unwinding that is comparable to its unwinding capacity during elongation. However, mutant DBP proteins defective in unwinding and elongation can still enhance initiation on ds templates. DBP also stimulates the binding of nuclear factor I (NFI) to the origin and lowers the K m for coupling of the first nucleotide to the precursor terminal protein by Pol. Mobility shift experiments reveal that DBP stimulates the binding of Pol on double-stranded origin and nonorigin DNA but not on single-stranded DNA. This effect is specific for DBP and is also seen with other DNA Pols. Our results suggest that, rather than by origin unwinding, DBP enhances initiation by modulating the origin conformation such that DNA Pol can bind more efficiently.

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“…The N terminus is able to stimulate adenovirus DNA replication by up to a factor of 50, and it has been shown that this stimulation does not require the NFI/CTF C terminus (9,11,12). NFI/CTF directly binds to the adenoviral DNA-polymerase, which is assumed to stabilize the preinitiation complex (13,14). 2 However, the cellular function of the NFI/CTF proteins has not yet been completely elucidated.…”

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confidence: 99%

Identification of Pirin, a Novel Highly Conserved Nuclear Protein

Wendler

Kremmer²,

Förster

et al. 1997

Journal of Biological Chemistry

116

134

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Nuclear factor I enhances adenovirus DNA replication by increasing the stability of a preinitiation complex.

Cited by 73 publications

References 64 publications

Nuclear Factor 1 Is Required for Both Hormone-Dependent Chromatin Remodeling and Transcriptional Activation of the Mouse Mammary Tumor Virus Promoter

Nuclear Factor 1 Is Required for Both Hormone-Dependent Chromatin Remodeling and Transcriptional Activation of the Mouse Mammary Tumor Virus Promoter

Adenovirus Type 5 DNA Binding Protein Stimulates Binding of DNA Polymerase to the Replication Origin

Identification of Pirin, a Novel Highly Conserved Nuclear Protein

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