The human transcriptional repressor protein NAB1: expression and biological activity

Thiel, Gerald; Kaufmann, Katrin; Magin, Angela; Lietz, Michael; Bach, Karl; Cramer, Matthias

doi:10.1016/s0167-4781(00)00207-4

Cited by 102 publications

(121 citation statements)

References 42 publications

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“…21 4 -luc harbors four copies of the minimal Egr-1-responsive element linked to luc. 22 ASMA-luc harbors a 1.1-kb promoter fragment from the mouse alpha smooth muscle actin (ASMA; gene symbol, ACTA) gene upstream of luc. 23 Fibroblasts at early confluence were transfected with the indicated constructs using a kit (SuperFect Transfection kit; Qiagen).…”

Section: Plasmids and Transient Transfection Assaysmentioning

confidence: 99%

The Early Growth Response Gene Egr2 (Alias Krox20) Is a Novel Transcriptional Target of Transforming Growth Factor-β that Is Up-Regulated in Systemic Sclerosis and Mediates Profibrotic Responses

Fang

Ooka

Bhattachyya

et al. 2011

The American Journal of Pathology

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Although the early growth response-2 (Egr-2, alias Krox20) protein shows structural and functional similarities to Egr-1, these two related early-immediate transcription factors are nonredundant. Egr-2 plays essential roles in peripheral nerve myelination, adipogenesis, and immune tolerance; however, its regulation and role in tissue repair and fibrosis remain poorly understood. We show herein that transforming growth factor (TGF)-␤ induced a Smad3-dependent sustained stimulation of Egr2 gene expression in normal fibroblasts. Overexpression of Egr-2 was sufficient to stimulate collagen gene expression and myofibroblast differentiation, whereas these profibrotic TGF-␤ responses were attenuated in Egr-2-depleted fibroblasts. Genomewide transcriptional profiling revealed that multiple genes associated with tissue remodeling and wound healing were up-regulated by Egr-2, but the Egr-2-regulated gene expression profile overlapped only partially with the Egr-1-regulated gene profile. Levels of Egr-2 were elevated in lesional tissue from mice with bleomycin-induced scleroderma. Moreover, elevated Egr-2 was noted in biopsy specimens of skin and lung from patients with systemic sclerosis.These results provide the first evidence that Egr-2 is a functionally distinct transcription factor that is both necessary and sufficient for TGF-␤-induced profibrotic responses and is aberrantly expressed in lesional tissue in systemic sclerosis and in a murine model of scleroderma. Together, these findings suggest that Egr-2 plays an important nonredundant role in the pathogenesis of fibrosis. Targeting Egr-2 might represent a novel therapeutic strategy to control fibrosis.

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Section: Plasmids and Transient Transfection Assaysmentioning

confidence: 99%

The Early Growth Response Gene Egr2 (Alias Krox20) Is a Novel Transcriptional Target of Transforming Growth Factor-β that Is Up-Regulated in Systemic Sclerosis and Mediates Profibrotic Responses

Fang

Ooka

Bhattachyya

et al. 2011

The American Journal of Pathology

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“…The plasmid was cut with PmeI and BglII and cloned upstream of the luciferase gene, generating the lentiviral transfer vector pFWInsluc. Cell extracts of stimulated cells were prepared using reporter lysis buffer (Promega) and analyzed for luciferase activities as described (33). Luciferase activity was normalized to the protein concentration.…”

Section: Methodsmentioning

confidence: 99%

“…These proteins bind to Egr-1 and block transcriptional activation via Egr-1 (33,39,40). Thus, elevated Egr-1 protein levels do not automatically indicate an increased transcription of Egr-1 target genes.…”

Section: Stimulation Of Ins-1 Pancreatic ␤-Cells With Pregnenolone Sumentioning

confidence: 99%

Signal Transduction of Pregnenolone Sulfate in Insulinoma Cells

Mayer¹,

Muller²,

Mannebach

et al. 2011

Journal of Biological Chemistry

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The neurosteroid pregnenolone sulfate acts on the nervous system by modifying neurotransmission and receptor functions, thus influencing synaptic strength, neuronal survival, and neurogenesis. Here we show that pregnenolone sulfate induces a signaling cascade in insulinoma cells leading to enhanced expression of the zinc finger transcription factor Egr-1 and Egr-1-responsive target genes. Pharmacological and genetic experiments revealed that influx of Ca 2؉ ions via transient receptor potential M3 and voltage-gated Ca 2؉ channels, elevation of the cytosolic Ca 2؉ level, and activation of ERK are essential for connecting pregnenolone sulfate stimulation with enhanced Egr-1 biosynthesis. Expression of a dominant-negative mutant of Elk-1, a key regulator of gene transcription driven by a serum response element, attenuated Egr-1 expression following stimulation, indicating that Elk-1 or related ternary complex factors connect the transcription of the Egr-1 gene with the pregnenolone sulfate-induced intracellular signaling cascade elicited by the initial influx of Ca 2؉ . The newly synthesized Egr-1 was biologically active and bound under physiological conditions to the regulatory regions of the Pdx-1, Synapsin I, and Chromogranin B genes. Pdx-1 is a major regulator of insulin gene transcription. Accordingly, elevated insulin promoter activity and increased mRNA levels of insulin could be detected in pregnenolone sulfate-stimulated insulinoma cells. Likewise, the biosynthesis of synapsin I, a synaptic vesicle protein that is found at secretory granules in insulinoma cells, was stimulated in pregnenolone sulfate-treated INS-1 cells. Together, these data show that pregnenolone sulfate induces a signaling cascade in insulinoma cells that is very similar to the signaling cascade induced by glucose in ␤-cells.Steroids synthesized in the central and peripheral nervous system that are, at least in part, independent of steroidogenic gland secretion are termed neurosteroids. They include progesterone, pregnenolone, pregnenolone sulfate, and dehydroepiandrosterone. Pregnenolone sulfate directly acts in the nervous system by modifying neurotransmission, receptor functions, and the strength of synaptic transmission (1). Stimulation with pregnenolone sulfate has been shown to exert modulatory effects on several types of receptors and ion channels including the N-methyl-D-aspartate receptor, the ␥-amino butyric acid-A receptor (1-6), voltage-gated Ca 2ϩ channels, and Kir2.3 K ϩ channels (5, 7-9). Intracerebral infusions of pregnenolone sulfate was shown to influence cognitive processes, neuronal survival, and neurogenesis (10, 11). Interestingly, the molecular cell biology of ␤-cells shows remarkable similarity to that of neurons. Neuronal genes are not only expressed in neurons, but also in endocrine cells. Pancreatic ␤-cells express synaptic vesicle proteins such as synapsin I, synaptophysin or synaptotagmin, neurotransmitters, and neurotransmitter-synthesizing enzymes. In line with this, it has recently been reported that the n...

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“…Transcriptional Repression Assays-We used the assay described by Thiel et al (36,37). For these experiments, EED, NIPP1, and the indicated mutants were subcloned in the mammalian expression vector pM in-frame with the GAL4 DNA-binding domain (residues 1-147).…”

Section: Methodsmentioning

confidence: 99%

“…The vector encoding only the GAL4 DNAbinding domain was used as negative control. As positive controls, we expressed fusions of the GAL4 DNA-binding domain and either the transcriptional repression domain of NK10 (residues 1-112) (37,42) or the transcriptional co-repressor NAB1 (36). The plasmids were transiently co-expressed in COS-1 cells with a reporter luciferase gene plasmid.…”

Section: Fig 2 Co-immunoprecipitation and Gst Pull-down Experimentsmentioning

confidence: 99%

The Protein Phosphatase-1 (PP1) Regulator, Nuclear Inhibitor of PP1 (NIPP1), Interacts with the Polycomb Group Protein, Embryonic Ectoderm Development (EED), and Functions as a Transcriptional Repressor

Jin

Eynde

Beullens

et al. 2003

Journal of Biological Chemistry

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The nuclear protein NIPP1 (nuclear inhibitor of protein Ser/Thr phosphatase-1) interacts with the splicing factors SAP155 and CDC5L and is involved in a late step of spliceosome assembly. In addition, NIPP1 is an interactor of protein phosphatase-1 and a COOH-terminal NIPP1 fragment displays an RNase E like endoribonuclease activity. A yeast two-hybrid screening resulted in the identification of the Polycomb group protein EED (embryonic ectoderm development), an established transcriptional repressor, as a novel NIPP1 interactor. NIPP1 only interacted with full-length EED, whereas two EED interaction domains were mapped to the central and COOH-terminal thirds of NIPP1. The NIPP1-EED interaction was potentiated by the binding of (d)Grich nucleic acids to the central domain of NIPP1. Nucleic acids also decreased the potency of NIPP1 as an inhibitor of PP1, but they did not prevent the formation of a ternary NIPP1⅐EED⅐PP1 complex. EED had no effect on the function of NIPP1 as a splicing factor or as an endoribonuclease. However, similar to EED, NIPP1 acted as a transcriptional repressor of targeted genes and this NIPP1 effect was mediated by the EED interaction domain. Also, the histone deacetylase 2 was present in a complex with NIPP1. Our data are in accordance with a role for NIPP1 as a DNA-targeting protein for EED and associated chromatin-modifying enzymes.NIPP1 1 (39 kDa, 351 residues) is a ubiquitously expressed nuclear protein that was originally discovered as a potent and specific inhibitor of protein Ser/Thr phosphatase-1 (PP1), hence its name nuclear inhibitor of PP1 (1). NIPP1 contains binding sites for PP1 in its central and COOH-terminal domains (2,3) and is complexed to 30 -50% of the nuclear pool of PP1 (4). The NIPP1-PP1 holoenzyme in nuclear extracts is inactive but can be activated by the phosphorylation of NIPP1 with protein kinase A (Ser-199), protein kinase CK2 (Ser-204), or protein tyrosine kinases of the Src family (Tyr-335) (3, 5-7). More recently, we demonstrated that NIPP1 is required for a late step in the assembly of spliceosomes (8), which are the complexes of small nuclear RNAs and proteins that catalyze pre-mRNA splicing. The splicing function of NIPP1 depends on the NH 2 -terminal third (residues 1-142) of NIPP1, which largely consists of a forkhead-associated (FHA) domain, and on residues 225-329 in the COOH-terminal domain of NIPP1. The FHA domain of NIPP1 interacts with phosphorylated forms of the splicing factors SAP155 (9) and CDC5L (10), which are components of the U2 small nuclear ribonucleoprotein particle and U4/U5/U6 tri-small nuclear ribonucleoprotein particles, respectively. It is not known how residues 225-329 of NIPP1 contribute to spliceosome assembly. The extreme COOH terminus of NIPP1 (residues 329 -351) does not appear to be involved in spliceosome assembly but has binding sites for PP1 and for A/U-rich single-stranded nucleic acids (3, 11). In addition, a synthetic peptide corresponding to residues 329 -351 as well as NIPP1-(225-351), which may exist as a splice va...

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The human transcriptional repressor protein NAB1: expression and biological activity

Cited by 102 publications

References 42 publications

The Early Growth Response Gene Egr2 (Alias Krox20) Is a Novel Transcriptional Target of Transforming Growth Factor-β that Is Up-Regulated in Systemic Sclerosis and Mediates Profibrotic Responses

The Early Growth Response Gene Egr2 (Alias Krox20) Is a Novel Transcriptional Target of Transforming Growth Factor-β that Is Up-Regulated in Systemic Sclerosis and Mediates Profibrotic Responses

Signal Transduction of Pregnenolone Sulfate in Insulinoma Cells

The Protein Phosphatase-1 (PP1) Regulator, Nuclear Inhibitor of PP1 (NIPP1), Interacts with the Polycomb Group Protein, Embryonic Ectoderm Development (EED), and Functions as a Transcriptional Repressor

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