scholarly journals Zyxin and cCRP: two interactive LIM domain proteins associated with the cytoskeleton.

1992 ◽  
Vol 119 (6) ◽  
pp. 1573-1587 ◽  
Author(s):  
I Sadler ◽  
A W Crawford ◽  
J W Michelsen ◽  
M C Beckerle
Keyword(s):  
Gene Expression ◽  
Transcriptional Regulation ◽  
Protein Interactions ◽  
Signal Transduction Pathway ◽  
Cytoskeletal Proteins ◽  
Specific Gene ◽  
Sequence Motif ◽  
Lim Domains

Interaction with extracellular matrix can trigger a variety of responses by cells including changes in specific gene expression and cell differentiation. The mechanism by which cell surface events are coupled to the transcriptional machinery is not understood, however, proteins localized at sites of cell-substratum contact are likely to function as signal transducers. We have recently purified and characterized a low abundance adhesion plaque protein called zyxin (Crawford, A. W., and M. C. Beckerle. 1991. J. Biol. Chem. 266:5847-5853; Crawford, A. W., J. W. Michelsen, and M. C. Beckerle. 1992. J. Cell Biol. 116:1381-1393). We have now isolated and sequenced zyxin cDNA and we report here that zyxin exhibits an unusual proline-rich NH2-terminus followed by three tandemly arrayed LIM domains. LIM domains have previously been identified in proteins that play important roles in transcriptional regulation and cellular differentiation. LIM domains have been proposed to coordinate metal ions and we have demonstrated by atomic absorption spectroscopy that purified zyxin binds zinc, a result consistent with the idea that zyxin has zinc fingers. In addition, we have discovered that zyxin interacts in vitro with a 23-kD protein that also exhibits LIM domains. Microsequence analysis has revealed that the 23-kD protein (or cCRP) is the chicken homologue of the human cysteine-rich protein (hCRP). By double-label indirect immunofluorescence, we found that zyxin and cCRP are extensively colocalized in chicken embryo fibroblasts, consistent with the idea that they interact in vivo. We conclude that LIM domains are zinc-binding sequences that may be involved in protein-protein interactions. The demonstration that two cytoskeletal proteins, zyxin and cCRP, share a sequence motif with proteins important for transcriptional regulation raises the possibility that zyxin and cCRP are components of a signal transduction pathway that mediates adhesion-stimulated changes in gene expression.

Serial analysis of gene expression (SAGE) during porcine embryo development

2004 ◽  
Vol 16 (2) ◽  
pp. 87 ◽  
Author(s):  
Le Ann Blomberg ◽  
Kurt A. Zuelke
Keyword(s):  
Gene Expression ◽  
Functional Genomics ◽  
Embryo Development ◽  
Molecular Mechanisms ◽  
Physiological Role ◽  
Transgenic Animals ◽  
Specific Gene ◽  
Research Strategies

Functional genomics provides a powerful means for delving into the molecular mechanisms involved in pre-implantation development of porcine embryos. High rates of embryonic mortality (30%), following either natural mating or artificial insemination, emphasise the need to improve the efficiency of reproduction in the pig. The poor success rate of live offspring from in vitro-manipulated pig embryos also hampers efforts to generate transgenic animals for biotechnology applications. Previous analysis of differential gene expression has demonstrated stage-specific gene expression for in vivo-derived embryos and altered gene expression for in vitro-derived embryos. However, the methods used to date examine relatively few genes simultaneously and, thus, provide an incomplete glimpse of the physiological role of these genes during embryogenesis. The present review will focus on two aspects of applying functional genomics research strategies for analysing the expression of genes during elongation of pig embryos between gestational day (D) 11 and D12. First, we compare and contrast current methodologies that are being used for gene discovery and expression analysis during pig embryo development. Second, we establish a paradigm for applying serial analysis of gene expression as a functional genomics tool to obtain preliminary information essential for discovering the physiological mechanisms by which distinct embryonic phenotypes are derived.

scholarly journals A Dual Role for Oncostatin M Signaling in the Differentiation and Death of Mammary Epithelial Cells in Vivo

2008 ◽  
Vol 22 (12) ◽  
pp. 2677-2688 ◽  
Author(s):  
Paul G. Tiffen ◽  
Nader Omidvar ◽  
Nuria Marquez-Almuina ◽  
Dawn Croston ◽  
Christine J. Watson ◽  
...  
Keyword(s):  
Gene Expression ◽  
Epithelial Cell ◽  
Epithelial Cells ◽  
Mammary Epithelial Cells ◽  
Mammary Epithelial ◽  
Oncostatin M ◽  
Specific Gene ◽  
Mammary Involution

Abstract Recent studies in breast cancer cell lines have shown that oncostatin M (OSM) not only inhibits proliferation but also promotes cell detachment and enhances cell motility. In this study, we have looked at the role of OSM signaling in nontransformed mouse mammary epithelial cells in vitro using the KIM-2 mammary epithelial cell line and in vivo using OSM receptor (OSMR)-deficient mice. OSM and its receptor were up-regulated approximately 2 d after the onset of postlactational mammary regression, in response to leukemia inhibitory factor (LIF)-induced signal transducer and activator of transcription-3 (STAT3). This resulted in sustained STAT3 activity, increased epithelial apoptosis, and enhanced clearance of epithelial structures during the remodeling phase of mammary involution. Concurrently, OSM signaling precipitated the dephosphorylation of STAT5 and repressed expression of the milk protein genes β-casein and whey acidic protein (WAP). Similarly, during pregnancy, OSM signaling suppressed β-casein and WAP gene expression. In vitro, OSM but not LIF persistently down-regulated phosphorylated (p)-STAT5, even in the continued presence of prolactin. OSM also promoted the expression of metalloproteinases MMP3, MMP12, and MMP14, which, in vitro, were responsible for OSM-specific apoptosis. Thus, the sequential activation of IL-6-related cytokines during mammary involution culminates in an OSM-dependent repression of epithelial-specific gene expression and the potentiation of epithelial cell extinction mediated, at least in part, by the reciprocal regulation of p-STAT5 and p-STAT3.

scholarly journals Cyclic AMP-dependent protein kinase inhibits the activity of myogenic helix-loop-helix proteins.

1992 ◽  
Vol 12 (10) ◽  
pp. 4478-4485 ◽  
Author(s):  
L Li ◽  
R Heller-Harrison ◽  
M Czech ◽  
E N Olson
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Transcriptional Activation ◽  
Consensus Sequence ◽  
Signal Transduction Pathway ◽  
Specific Gene ◽  
Dependent Protein Kinase ◽  
Dependent Protein

Differentiation of skeletal muscle cells is inhibited by the cyclic AMP (cAMP) signal transduction pathway. Here we report that the catalytic subunit of cAMP-dependent protein kinase (PKA) can substitute for cAMP and suppress muscle-specific transcription by silencing the activity of the MyoD family of regulatory factors, which includes MyoD, myogenin, myf5, and MRF4. Repression by the PKA catalytic (C) subunit is directed at the consensus sequence CANNTG, the target for DNA binding and transcriptional activation by these myogenic regulators. Phosphopeptide mapping of myogenin in vitro and in vivo revealed two PKA phosphorylation sites, both within the basic region. However, repression of myogenin function by PKA does not require direct phosphorylation of these sites but instead involves an indirect mechanism with one or more intermediate steps. Regulation of the transcriptional activity of the MyoD family by modulation of the cAMP signaling pathway may account for the inhibitory effects of certain peptide growth factors on muscle-specific gene expression and may also determine the responsiveness of different cell types to myogenic conversion by these myogenic regulators.

Cyclic AMP-dependent protein kinase inhibits the activity of myogenic helix-loop-helix proteins

1992 ◽  
Vol 12 (10) ◽  
pp. 4478-4485
Author(s):  
L Li ◽  
R Heller-Harrison ◽  
M Czech ◽  
E N Olson
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Transcriptional Activation ◽  
Consensus Sequence ◽  
Signal Transduction Pathway ◽  
Specific Gene ◽  
Dependent Protein Kinase ◽  
Dependent Protein

Differentiation of skeletal muscle cells is inhibited by the cyclic AMP (cAMP) signal transduction pathway. Here we report that the catalytic subunit of cAMP-dependent protein kinase (PKA) can substitute for cAMP and suppress muscle-specific transcription by silencing the activity of the MyoD family of regulatory factors, which includes MyoD, myogenin, myf5, and MRF4. Repression by the PKA catalytic (C) subunit is directed at the consensus sequence CANNTG, the target for DNA binding and transcriptional activation by these myogenic regulators. Phosphopeptide mapping of myogenin in vitro and in vivo revealed two PKA phosphorylation sites, both within the basic region. However, repression of myogenin function by PKA does not require direct phosphorylation of these sites but instead involves an indirect mechanism with one or more intermediate steps. Regulation of the transcriptional activity of the MyoD family by modulation of the cAMP signaling pathway may account for the inhibitory effects of certain peptide growth factors on muscle-specific gene expression and may also determine the responsiveness of different cell types to myogenic conversion by these myogenic regulators.

scholarly journals Epigenetic regulation of neural cell differentiation plasticity in the adult mammalian brain

2008 ◽  
Vol 105 (46) ◽  
pp. 18012-18017 ◽  
Author(s):  
Jun Kohyama ◽  
Takuro Kojima ◽  
Eriko Takatsuka ◽  
Toru Yamashita ◽  
Jun Namiki ◽  
...  
Keyword(s):  
Gene Expression ◽  
Target Genes ◽  
Epigenetic Modification ◽  
Mammalian Brain ◽  
Cytokine Signaling ◽  
Specific Gene ◽  
Neural Cells ◽  
Specific Gene Expression

Neural stem/progenitor cells (NSCs/NPCs) give rise to neurons, astrocytes, and oligodendrocytes. It has become apparent that intracellular epigenetic modification including DNA methylation, in concert with extracellular cues such as cytokine signaling, is deeply involved in fate specification of NSCs/NPCs by defining cell-type specific gene expression. However, it is still unclear how differentiated neural cells retain their specific attributes by repressing cellular properties characteristic of other lineages. In previous work we have shown that methyl-CpG binding protein transcriptional repressors (MBDs), which are expressed predominantly in neurons in the central nervous system, inhibit astrocyte-specific gene expression by binding to highly methylated regions of their target genes. Here we report that oligodendrocytes, which do not express MBDs, can transdifferentiate into astrocytes both in vitro (cytokine stimulation) and in vivo (ischemic injury) through the activation of the JAK/STAT signaling pathway. These findings suggest that differentiation plasticity in neural cells is regulated by cell-intrinsic epigenetic mechanisms in collaboration with ambient cell-extrinsic cues.

scholarly journals c-Jun Homodimers Can Function as a Context-Specific Coactivator

2007 ◽  
Vol 27 (8) ◽  
pp. 2919-2933 ◽  
Author(s):  
Benoit Grondin ◽  
Martin Lefrancois ◽  
Mathieu Tremblay ◽  
Marianne Saint-Denis ◽  
André Haman ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Dna Binding ◽  
Rna Polymerase Ii ◽  
Protein Interactions ◽  
Expression Profiles ◽  
Basic Domain ◽  
Interaction Mode

ABSTRACT Transcription factors can function as DNA-binding-specific activators or as coactivators. c-Jun drives gene expression via binding to AP-1 sequences or as a cofactor for PU.1 in macrophages. c-Jun heterodimers bind AP-1 sequences with higher affinity than homodimers, but how c-Jun works as a coactivator is unknown. Here, we provide in vitro and in vivo evidence that c-Jun homodimers are recruited to the interleukin-1β (IL-1β) promoter in the absence of direct DNA binding via protein-protein interactions with DNA-anchored PU.1 and CCAAT/enhancer-binding protein β (C/EBPβ). Unexpectedly, the interaction interface with PU.1 and C/EBPβ involves four of the residues within the basic domain of c-Jun that contact DNA, indicating that the capacities of c-Jun to function as a coactivator or as a DNA-bound transcription factor are mutually exclusive. Our observations indicate that the IL-1β locus is occupied by PU.1 and C/EBPβ and poised for expression and that c-Jun enhances transcription by facilitating a rate-limiting step, the assembly of the RNA polymerase II preinitiation complex, with minimal effect on the local chromatin status. We propose that the basic domain of other transcription factors may also be redirected from a DNA interaction mode to a protein-protein interaction mode and that this switch represents a novel mechanism regulating gene expression profiles.

scholarly journals OncogenicGata1causes stage-specific megakaryocyte differentiation delay

2019 ◽  
Author(s):  
Gaëtan Juban ◽  
Nathalie Sakakini ◽  
Hedia Chagraoui ◽  
Qian Cheng ◽  
Kelly Soady ◽  
...  
Keyword(s):  
Gene Expression ◽  
Es Cells ◽  
Erythroid Differentiation ◽  
Detailed Examination ◽  
S Phase ◽  
Myeloproliferative Disorder ◽  
Specific Gene ◽  
Specific Stage

AbstractThe megakaryocyte/erythroid Transient Myeloproliferative Disorder (TMD) in newborns with Down Syndrome (DS) occurs when N-terminal truncating mutations of the hemopoietic transcription factor GATA1, that produce GATA1short protein (GATA1s), are acquired early in development. Prior work has shown that murine GATA1s, by itself, causes a transient yolk sac myeloproliferative disorder. However, it is unclear where in the hemopoietic cellular hierarchy GATA1s exerts its effects to produce this myeloproliferative state. Here, through a detailed examination of hemopoiesis from murine GATA1s ES cells and GATA1s embryos we define defects in erythroid and megakaryocytic differentiation that occur relatively in hemopoiesis. GATA1s causes an arrest late in erythroid differentiationin vivo, and even more profoundly in ES-cell derived cultures, with a marked reduction of Ter-119 cells and reduced erythroid gene expression. In megakaryopoiesis, GATA1s causes a differentiation delay at a specific stage, with accumulation of immature, kit-expressing CD41himegakaryocytic cells. In this specific megakaryocytic compartment, there are increased numbers of GATA1s cells in S-phase of cell cycle and reduced number of apoptotic cells compared to GATA1 cells in the same cell compartment. There is also a delay in maturation of these immature GATA1s megakaryocytic lineage cells compared to GATA1 cells at the same stage of differentiation. Finally, even when GATA1s megakaryocytic cells mature, they mature aberrantly with altered megakaryocyte-specific gene expression and activity of the mature megakaryocyte enzyme, acetylcholinesterase. These studies pinpoint the hemopoietic compartment where GATA1s megakaryocyte myeloproliferation occurs, defining where molecular studies should now be focussed to understand the oncogenic action of GATA1s.Scientific CategoryHaematopoiesis and Stem CellsKey PointsGATA1s-induced stage-specific differentiation delay increases immature megakaryocytesin vivoandin vitro, during development.Differentiation delay is associated with increased numbers of cells in S-phase and reduced apoptosis.

scholarly journals Orphan Nuclear Receptor ERRγ Is a Novel Transcriptional Regulator of IL-6 Mediated Hepatic BMP6 Gene Expression in Mice

2020 ◽  
Vol 21 (19) ◽  
pp. 7148
Author(s):  
Kamalakannan Radhakrishnan ◽  
Yong-Hoon Kim ◽  
Yoon Seok Jung ◽  
Jina Kim ◽  
Don-Kyu Kim ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcriptional Regulation ◽  
Molecular Mechanism ◽  
Nuclear Receptor ◽  
Iron Homeostasis ◽  
Luciferase Reporter ◽  
Orphan Nuclear Receptor ◽  
Knock Out

Bone morphogenetic protein 6 (BMP6) is a multifunctional growth factor involved in organ development and homeostasis. BMP6 controls expression of the liver hormone, hepcidin, and thereby plays a crucial role in regulating iron homeostasis. BMP6 gene transcriptional regulation in liver is largely unknown, but would be of great help to externally modulate iron load in pathologic conditions. Here, we describe a detailed molecular mechanism of hepatic BMP6 gene expression by an orphan nuclear receptor, estrogen-related receptor γ (ERRγ), in response to the pro-inflammatory cytokine interleukin 6 (IL-6). Recombinant IL-6 treatment increases hepatic ERRγ and BMP6 expression. Overexpression of ERRγ is sufficient to increase BMP6 gene expression in hepatocytes, suggesting that IL-6 is upstream of ERRγ. In line, knock-down of ERRγ in cell lines or a hepatocyte specific knock-out of ERRγ in mice significantly decreases IL-6 mediated BMP6 expression. Promoter studies show that ERRγ directly binds to the ERR response element (ERRE) in the mouse BMP6 gene promoter and positively regulates BMP6 gene transcription in IL-6 treatment conditions, which is further confirmed by ERRE mutated mBMP6-luciferase reporter assays. Finally, an inverse agonist of ERRγ, GSK5182, markedly inhibits IL-6 induced hepatic BMP6 expression in vitro and in vivo. Taken together, these results reveal a novel molecular mechanism on ERRγ mediated transcriptional regulation of hepatic BMP6 gene expression in response to IL-6.

scholarly journals hsp72, a Host Determinant of Measles Virus Neurovirulence

2006 ◽  
Vol 80 (22) ◽  
pp. 11031-11039 ◽  
Author(s):  
Thomas Carsillo ◽  
Zachary Traylor ◽  
Changsun Choi ◽  
Stefan Niewiesk ◽  
Michael Oglesbee
Keyword(s):  
Gene Expression ◽  
Heat Shock ◽  
Heat Shock Protein ◽  
Protein Interactions ◽  
Measles Virus ◽  
Viral Rna ◽  
Viral Gene ◽  
Febrile Episodes

ABSTRACT Transient hyperthermia such as that experienced during febrile episodes increases expression of the major inducible 70-kDa heat shock protein (hsp72). Despite the relevance of febrile episodes to viral pathogenesis and the multiple in vitro roles of heat shock proteins in viral replication and gene expression, the in vivo significance of virus-heat shock protein interactions is unknown. The present work determined the in vivo relationship between hsp72 levels and neurovirulence of an hsp72-responsive virus using the mouse model of measles virus (MV) encephalitis. Transgenic C57BL/6 mice were created to constitutively overexpress hsp72 in neurons, and these mice were inoculated intracranially with Edmonston MV (Ed MV) at 42 h of age. The mean viral RNA burden in brain was approximately 2 orders of magnitude higher in transgenic animals than in nontransgenic animals 2 to 4 weeks postinfection, and this increased burden was associated with a fivefold increase in mortality. Mice were also challenged with an Ed MV variant exhibiting an attenuated in vitro response to hsp72-dependent stimulation of viral transcription (Ed N-522D). This virus exhibited an attenuated neuropathogenicity in transgenic mice, where mortality and viral RNA burdens were not significantly different from nontransgenic mice infected with either Ed N-522D or parent Ed MV. Collectively, these results indicate that hsp72 levels can serve as a host determinant of viral neurovirulence in C57BL/6 mice, reflecting the direct influence of hsp72 on viral gene expression.

scholarly journals The stringency and magnitude of androgen-specific gene activation are combinatorial functions of receptor and nonreceptor binding site sequences.

1993 ◽  
Vol 13 (10) ◽  
pp. 6326-6335 ◽  
Author(s):  
A J Adler ◽  
A Scheller ◽  
D M Robins
Keyword(s):  
Androgen Receptor ◽  
Protein Interactions ◽  
Hormonal Regulation ◽  
Steroid Receptors ◽  
Regulation Of Gene Expression ◽  
Gene Activation ◽  
Specific Gene ◽  
Sequence Variations

The mechanism by which specific hormonal regulation of gene expression is attained in vivo is a paradox in that several of the steroid receptors recognize the same DNA element in vitro. We have characterized a complex enhancer of the mouse sex-limited protein (Slp) gene that is activated exclusively by androgens but not by glucocorticoids in transfection. Potent androgen induction requires both the consensus hormone response element (HRE) and auxiliary elements residing within the 120-bp DNA fragment C' delta 9. Multiple nonreceptor factors are involved in androgen specificity, with respect to both the elevation of androgen receptor activity and the inactivity of glucocorticoid receptor (GR), since clustered base changes at any of several sites reduce or abolish androgen induction and do not increase glucocorticoid response. However, moving the HRE as little as 10 bases away from the rest of the enhancer allows GR to function, suggesting that GR is repressed by juxtaposition to particular factors within the androgen-specific complex. Surprisingly, some sequence variations of the HRE itself, within the context of C' delta 9, alter the stringency of specificity, as well as the magnitude, of hormonal response. These HRE sequence effects on expression correspond in a qualitative manner with receptor binding, i.e., GR shows a threefold difference in affinities for HREs amongst which androgen receptor does not discriminate. Altering the HRE orientation within the enhancer also affects hormonal stringency, increasing glucocorticoid but not androgen response. The effect of these subtle variations suggests that they alter receptor position with respect to other factors. Thus, protein-protein interactions that elicit specific gene regulation are established by the array of DNA elements in a complex enhancer and can be modulated by sequence variations within these elements that may influence selection of precise protein contacts.

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