scholarly journals Transactivation of gene expression by nuclear and cytoplasmic rel proteins.

1989 ◽  
Vol 9 (10) ◽  
pp. 4323-4336 ◽  
Author(s):  
M Hannink ◽  
H M Temin
Keyword(s):  
Gene Expression ◽  
Transcriptional Activation ◽  
Signal Transduction Pathway ◽  
Cellular Transformation ◽  
C Terminus ◽  
Intracellular Signal Transduction Pathway ◽  
Transforming Activity ◽  
A Cell ◽  
Rat Fibroblasts ◽  
Intracellular Signal

Transcriptional activation of gene expression by oncogenic proteins can lead to cellular transformation. It has recently been demonstrated that the protein encoded by the v-rel oncogene from reticuloendotheliosis virus strain T can transactivate gene expression from certain promoters in a cell-specific manner. We have examined the cytological location, transforming properties, and transactivation properties of proteins encoded by chimeric turkey v-rel/chicken c-rel genes. We found that whereas the v-rel protein was nuclear in both chicken embryo and rat fibroblasts, the presence of the C terminus of the c-rel protein inhibited nuclear localization of the rel protein in these fibroblasts. Cytoplasmic rel proteins containing C-terminal c-rel sequences transactivated gene expression from the polyomavirus late promoter as efficiently as did similar rel proteins located in the nucleus. These results indicate that the cellular location of rel proteins is not important for transactivation of gene expression and suggest that transactivation by rel proteins is indirect, perhaps by affecting an intracellular signal transduction pathway that eventually results in the alteration of gene expression. The transforming properties of the rel protein were unaltered by the presence of the c-rel C terminus, but, as previously reported for turkey c-rel sequences, substitution of chicken c-rel sequences for internal v-rel sequences reduced the transforming activity of the rel protein and eliminated the immortalization ability. However, all of the chimeric v/c-rel proteins were able to transactivate gene expression, indicating that transactivation does not correlate with transformation. These results suggest that transactivation may be necessary but is not sufficient for transformation by rel proteins.

Transactivation of gene expression by nuclear and cytoplasmic rel proteins

1989 ◽  
Vol 9 (10) ◽  
pp. 4323-4336
Author(s):  
M Hannink ◽  
H M Temin
Keyword(s):  
Gene Expression ◽  
Transcriptional Activation ◽  
Signal Transduction Pathway ◽  
Cellular Transformation ◽  
C Terminus ◽  
Intracellular Signal Transduction Pathway ◽  
Transforming Activity ◽  
A Cell ◽  
Rat Fibroblasts ◽  
Intracellular Signal

Transcriptional activation of gene expression by oncogenic proteins can lead to cellular transformation. It has recently been demonstrated that the protein encoded by the v-rel oncogene from reticuloendotheliosis virus strain T can transactivate gene expression from certain promoters in a cell-specific manner. We have examined the cytological location, transforming properties, and transactivation properties of proteins encoded by chimeric turkey v-rel/chicken c-rel genes. We found that whereas the v-rel protein was nuclear in both chicken embryo and rat fibroblasts, the presence of the C terminus of the c-rel protein inhibited nuclear localization of the rel protein in these fibroblasts. Cytoplasmic rel proteins containing C-terminal c-rel sequences transactivated gene expression from the polyomavirus late promoter as efficiently as did similar rel proteins located in the nucleus. These results indicate that the cellular location of rel proteins is not important for transactivation of gene expression and suggest that transactivation by rel proteins is indirect, perhaps by affecting an intracellular signal transduction pathway that eventually results in the alteration of gene expression. The transforming properties of the rel protein were unaltered by the presence of the c-rel C terminus, but, as previously reported for turkey c-rel sequences, substitution of chicken c-rel sequences for internal v-rel sequences reduced the transforming activity of the rel protein and eliminated the immortalization ability. However, all of the chimeric v/c-rel proteins were able to transactivate gene expression, indicating that transactivation does not correlate with transformation. These results suggest that transactivation may be necessary but is not sufficient for transformation by rel proteins.

ras-induced neuronal differentiation of PC12 cells: possible involvement of fos and jun

1989 ◽  
Vol 9 (8) ◽  
pp. 3174-3183
Author(s):  
P Sassone-Corsi ◽  
C J Der ◽  
I M Verma
Keyword(s):  
Signal Transduction ◽  
Neuronal Differentiation ◽  
Pc12 Cells ◽  
Transcriptional Activation ◽  
Signal Transduction Pathway ◽  
Cellular Transformation ◽  
Sympathetic Neuron ◽  
Binding Activity ◽  
Ras Protein ◽  
Dna Binding Activity

Rat pheochromocytoma PC12 cells differentiate to sympathetic neuron-like cells upon treatment with nerve growth factor (NGF). The ras and src transforming proteins also induce PC12 neuronal differentiation and are likely to involve the protein kinase C signal transduction pathway. Using a number of ras mutants, we have established that the domains of oncogenic ras protein responsible for PC12 differentiation overlap those required for cellular transformation. All of the ras mutants that induced neuronal differentiation also activated c-fos transcription through the dyad symmetry element (DSE). Transforming ras protein activated an intracellular signal pathway, which led to the induction of 12-O-tetradecanoyl phorbol-13-acetate-responsive elements; activation was enhanced by coexpression of the proto-oncogene jun (encoding AP-1) and was further augmented by fos. Nuclear extracts from ras-infected PC12 cells showed an increased AP-1 DNA-binding activity. Transcriptional activation by ras was independent of the cyclic AMP-dependent pathway of signal transduction. We propose a possible involvement of fos and jun in ras-induced differentiation.

scholarly journals ras-induced neuronal differentiation of PC12 cells: possible involvement of fos and jun.

1989 ◽  
Vol 9 (8) ◽  
pp. 3174-3183 ◽  
Author(s):  
P Sassone-Corsi ◽  
C J Der ◽  
I M Verma
Keyword(s):  
Signal Transduction ◽  
Neuronal Differentiation ◽  
Pc12 Cells ◽  
Transcriptional Activation ◽  
Signal Transduction Pathway ◽  
Cellular Transformation ◽  
Sympathetic Neuron ◽  
Binding Activity ◽  
Ras Protein ◽  
Dna Binding Activity

Rat pheochromocytoma PC12 cells differentiate to sympathetic neuron-like cells upon treatment with nerve growth factor (NGF). The ras and src transforming proteins also induce PC12 neuronal differentiation and are likely to involve the protein kinase C signal transduction pathway. Using a number of ras mutants, we have established that the domains of oncogenic ras protein responsible for PC12 differentiation overlap those required for cellular transformation. All of the ras mutants that induced neuronal differentiation also activated c-fos transcription through the dyad symmetry element (DSE). Transforming ras protein activated an intracellular signal pathway, which led to the induction of 12-O-tetradecanoyl phorbol-13-acetate-responsive elements; activation was enhanced by coexpression of the proto-oncogene jun (encoding AP-1) and was further augmented by fos. Nuclear extracts from ras-infected PC12 cells showed an increased AP-1 DNA-binding activity. Transcriptional activation by ras was independent of the cyclic AMP-dependent pathway of signal transduction. We propose a possible involvement of fos and jun in ras-induced differentiation.

scholarly journals Alternate RNA splicing of murine nfkb1 generates a nuclear isoform of the p50 precursor NF-kappa B1 that can function as a transactivator of NF-kappa B-regulated transcription.

1994 ◽  
Vol 14 (12) ◽  
pp. 8460-8470 ◽  
Author(s):  
R J Grumont ◽  
J Fecondo ◽  
S Gerondakis
Keyword(s):  
Gene Expression ◽  
Dna Binding ◽  
Rna Splicing ◽  
Coding Region ◽  
Nf Kappa B ◽  
Reading Frame ◽  
C Terminus ◽  
A Cell ◽  
Regulated Gene Expression

The NF-kappa B1 subunit of the transcription factor NF-kappa B is derived by proteolytic cleavage from the N terminus of a 105-kDa precursor protein. The C terminus of p105NF-kappa B1, like those of I kappa B proteins, contains ankyrin-related repeats that inhibit DNA binding and nuclear localization of the precursor and confer I kappa B-like properties upon p105NF-kappa B1. Here we report the characterization of two novel NF-kappa B1 precursor isoforms, p84NF-kappa B1 and p98NF-kappa B1, that arise by alternate splicing within the C-terminal coding region of murine nfkb1. p98NF-kappa B1, which lacks the 111 C-terminal amino acids (aa) of p105NF-kappa B1, has a novel 35-aa C terminus encoded by an alternate reading frame of the gene. p84NF-kappa B1 lacks the C-terminal 190 aa of p105NF-kappa B1, including part of ankyrin repeat 7. RNA and protein analyses indicated that the expression of p84NF-kappa B1 and p98NF-kappa B1 is restricted to certain tissues and that the phorbol myristate acetate-mediated induction of p84NF-kappa B1 and p105NF-kappa B1 differs in a cell-type-specific manner. Both p84NF-kappa B1 and p98NF-kappa B1 are found in the nuclei of transfected cells. Transient transfection analysis revealed that p98NF-kappa B1, but not p105NF-kappa B1 or p84NF-kappa B1, acts as a transactivator of NF-kappa B-regulated gene expression and that this is dependent on sequences in the Rel homology domain required for DNA binding and on the novel 35 C-terminal aa of this isoform. In contrast to previous findings, which indicated that p105NF-kappa B1 does not bind DNA, all of the NF-kappa B1 precursors were found to specifically bind with low affinity to a highly restricted set of NF-kappa B sites in vitro, thereby raising the possibility that certain of the NF-kappa B1 precursor isoforms may directly modulate gene expression.

scholarly journals Wheat Transcription Factor TaSNAC11-4B Positively Regulates Leaf Senescence through Promoting ROS Production in Transgenic Arabidopsis

2020 ◽  
Vol 21 (20) ◽  
pp. 7672
Author(s):  
Zenglin Zhang ◽  
Chen Liu ◽  
Yongfeng Guo
Keyword(s):  
Gene Expression ◽  
Stress Tolerance ◽  
Leaf Senescence ◽  
Transcriptional Activation ◽  
Genetic Manipulation ◽  
Ectopic Expression ◽  
Luciferase Assay ◽  
Yield Increase ◽  
C Terminus ◽  
Functional Homolog

Senescence is the final stage of leaf development which is accompanied by highly coordinated and complicated reprogramming of gene expression. Genetic manipulation of leaf senescence in major crops including wheat has been shown to be able to increase stress tolerance and grain yield. NAC(No apical meristem (NAM), ATAF1/2, and cup-shaped cotyledon (CUC)) transcription factors (TFs) play important roles in regulating gene expression changes during leaf senescence and in response to abiotic stresses. Here, we report the characterization of TaSNAC11-4B (Uniprot: A0A1D5XI64), a wheat NAC family member that acts as a functional homolog of AtNAP, a key regulator of leaf senescence in Arabidopsis. The expression of TaSNAC11-4B was up-regulated with the progression of leaf senescence, in response to abscisic acid (ABA) and drought treatments in wheat. Ectopic expression of TaSNAC11-4B in Arabidopsis promoted ROS accumulation and significantly accelerated age-dependent as well as drought- and ABA-induced leaf senescence. Results from transcriptional activity assays indicated that the TaSNAC11-4B protein displayed transcriptional activation activities that are dependent on its C terminus. Furthermore, qRT-PCR and dual-Luciferase assay results suggested that TaSNAC11-4B could positively regulate the expression of AtrbohD and AtrbohF, which encode catalytic subunits of the ROS-producing NADPH oxidase. Further analysis of TaSNAC11-4B in wheat senescence and the potential application of this gene in manipulating leaf senescence with the purpose of yield increase and stress tolerance is discussed.

scholarly journals MyD88 Is a Key Mediator of Anorexia, But Not Weight Loss, Induced by Lipopolysaccharide and Interleukin-1β

Endocrinology ◽  
2006 ◽  
Vol 147 (9) ◽  
pp. 4445-4453 ◽  
Author(s):  
Kayoko Ogimoto ◽  
Marvin K. Harris ◽  
Brent E. Wisse
Keyword(s):  
Weight Loss ◽  
Food Intake ◽  
Signal Transduction Pathway ◽  
Toll Like Receptor 4 ◽  
Physiological Regulation ◽  
Intracellular Signal Transduction Pathway ◽  
Intracellular Signal ◽  
Myd88 Signaling ◽  
Deficient Mice ◽  
Pituitary Adrenal Axis

Systemic inflammatory signals can disrupt the physiological regulation of energy balance, causing anorexia and weight loss. In the current studies, we investigated whether MyD88, the primary, but not exclusive, intracellular signal transduction pathway for Toll-like receptor 4 and IL-1 receptor I, is necessary for anorexia and weight loss to occur in response to stimuli that activate these key innate immune receptors. Our findings demonstrate that the absence of MyD88 signaling confers complete protection against anorexia induced by either lipopolysaccharide (LPS) (20 h food intake in MyD88−/− mice 5.4 ± 0.3 vs. 3.3 ± 0.4 g in MyD88+/+ control mice, P < 0.001) or IL-1β (20 h food intake in MyD88−/− mice 4.9 ± 0.5 vs. 4.0 ± 0.3 g in MyD88+/+ control mice, P < 0.001). However, absent MyD88 signaling does not prevent these inflammatory mediators from causing weight loss (LPS, −0.4 ± 0.1 g; IL1β, −0.1 ± 0.1 g, both P < 0.01 vs. vehicle-injected MyD88−/− mice, +0.4 ± 0.2 g). Furthermore, LPS-induced weight loss occurs in the absence of adipsia, fever, or hypothalamus-pituitary-adrenal axis activation in MyD88-deficient mice. In addition, the peripheral inflammatory response to LPS is surprisingly intact in mice lacking MyD88. Together, these observations indicate that LPS reduces food intake via a mechanism that is dissociated from its effect on peripheral cytokine production, and whereas the presence of circulating proinflammatory cytokines per se is insufficient to cause anorexia in the absence of MyD88 signaling, it may contribute to LPS-induced weight loss.

scholarly journals Spatial proximity of homologous alleles and long noncoding RNAs regulate a switch in allelic gene expression

2015 ◽  
Vol 112 (13) ◽  
pp. E1577-E1586 ◽  
Author(s):  
Kalliopi Stratigi ◽  
Manouela Kapsetaki ◽  
Michalis Aivaliotis ◽  
Terrence Town ◽  
Richard A. Flavell ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcriptional Activation ◽  
Gene Expression Regulation ◽  
Noncoding Rnas ◽  
Long Noncoding Rnas ◽  
Fine Tuning ◽  
Allelic Expression ◽  
Spatial Proximity ◽  
Mrna Levels ◽  
A Cell

Physiological processes rely on the regulation of total mRNA levels in a cell. In diploid organisms, the transcriptional activation of one or both alleles of a gene may involve trans-allelic interactions that provide a tight spatial and temporal level of gene expression regulation. The mechanisms underlying such interactions still remain poorly understood. Here, we demonstrate that lipopolysaccharide stimulation of murine macrophages rapidly resulted in the actin-mediated and transient homologous spatial proximity of Tnfα alleles, which was necessary for the mono- to biallelic switch in gene expression. We identified two new complementary long noncoding RNAs transcribed from the TNFα locus and showed that their knockdown had opposite effects in Tnfα spatial proximity and allelic expression. Moreover, the observed spatial proximity of Tnfα alleles depended on pyruvate kinase muscle isoform 2 (PKM2) and T-helper-inducing POZ-Krüppel-like factor (ThPOK). This study suggests a role for lncRNAs in the regulation of somatic homologous spatial proximity and allelic expression control necessary for fine-tuning mammalian immune responses.

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