scholarly journals Development of three different cell types is associated with the activity of a specific MYB transcription factor in the ventral petal of Antirrhinum majus flowers

Development ◽  
2005 ◽  
Vol 132 (2) ◽  
pp. 359-370 ◽  
Author(s):  
M. Perez-Rodriguez
Keyword(s):  
Transcription Factor ◽  
Cell Types ◽  
Antirrhinum Majus ◽  
Myb Transcription Factor ◽  
Different Cell Types

scholarly journals Repression of Virus-Induced Interferon A Promoters by Homeodomain Transcription Factor Ptx1

2000 ◽  
Vol 20 (20) ◽  
pp. 7527-7540 ◽  
Author(s):  
Sébastien Lopez ◽  
Marie-Laure Island ◽  
Jacques Drouin ◽  
Marie-Thérese Bandu ◽  
Nicolas Christeff ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Differential Expression ◽  
Antisense Rna ◽  
Differentially Express ◽  
Regulatory Element ◽  
Cell Types ◽  
Functional Feature ◽  
Homeodomain Transcription Factor ◽  
Responsive Element ◽  
Different Cell Types

ABSTRACT Interferon A (IFN-A) genes are differentially expressed after virus induction. The differential expression of individual IFN-A genes is modulated by substitutions in the proximal positive virus responsive element A (VRE-A) of their promoters and by the presence or absence of a distal negative regulatory element (DNRE). The functional feature of the DNRE is to specifically act by repression of VRE-A activity. With the use of the yeast one-hybrid system, we describe here the identification of a specific DNRE-binding protein, the pituitary homeobox 1 (Ptx1 or Pitx1). Ptx1 is detectable in different cell types that differentially express IFN-A genes, and the endogenous Ptx1 protein binds specifically to the DNRE. Upon virus induction, Ptx1 negatively regulates the transcription of DNRE-containing IFN-A promoters, and the C-terminal region, as well as the homeodomain of the Ptx1 protein, is required for this repression. After virus induction, the expression of the Ptx1 antisense RNA leads to a significant increase of endogenous IFN-A gene transcription and is able to modify the pattern of differential expression of individual IFN-A genes. These studies suggest that Ptx1 contributes to the differential transcriptional strength of the promoters of different IFN-A genes and that these genes may provide new targets for transcriptional regulation by a homeodomain transcription factor.

scholarly journals Positive and negative regulation of c-Myb by cyclin D1, cyclin-dependent kinases, and p27 Kip1

Blood ◽  
2005 ◽  
Vol 105 (10) ◽  
pp. 3855-3861 ◽  
Author(s):  
Wanli Lei ◽  
Fan Liu ◽  
Scott A. Ness
Keyword(s):  
Cell Cycle ◽  
Transcription Factor ◽  
Cyclin D1 ◽  
Target Genes ◽  
Cell Types ◽  
Myb Transcription Factor ◽  
Human T Cells ◽  
Transforming Activity ◽  
Differentiation And Proliferation ◽  
P27 Kip1

AbstractThe c-Myb transcription factor controls differentiation and proliferation in hematopoietic and other cell types and has latent transforming activity, but little is known about its regulation during the cell cycle. Here, c-Myb was identified as part of a protein complex from human T cells containing the cyclin-dependent kinase (CDK) CDK6. Assays using model reporter constructs as well as endogenous target genes showed that the activity of c-Myb was inhibited by cyclin D1 plus CDK4 or CDK6 but stimulated by expression of the CDK inhibitors p16 Ink4a, p21 Cip1, or p27 Kip1. Mapping experiments identified a highly conserved region in c-Myb which, when transferred to the related A-Myb transcription factor, also rendered it responsive to CDKs and p27. The results suggest that c-Myb activity is directly regulated by cyclin D1 and CDKs and imply that c-Myb activity is regulated during the cell cycle in hematopoietic cells.

scholarly journals Lmx1b influences correct post-mitotic coding of mesodiencephalic dopaminergic neurons

2018 ◽  
Author(s):  
Iris Wever ◽  
Pablo Largo Barrientos ◽  
Elisa J. Hoekstra ◽  
Marten P. Smidt
Keyword(s):  
Transcription Factor ◽  
Dopaminergic Neurons ◽  
Cell Types ◽  
Late Development ◽  
Genetic Ablation ◽  
Depth Analysis ◽  
Homeobox Transcription Factor ◽  
Different Cell Types ◽  
Transcription Factor 1 ◽  
Inductive Activity

AbstractThe Lim Homeobox transcription factor 1 beta (LMX1b) has been identified as one of the transcription factors important for the development of mesodiencephalic dopaminergic (mdDA) neurons. During early development, Lmx1b is essential for induction and maintenance of the Isthmic Organizer (IsO), and genetic ablation results in the disruption of inductive activity from the IsO and loss of properly differentiated mdDA neurons.To study the downstream targets of Lmx1b without affecting the IsO, we generated a conditional model in which Lmx1b was selectively deleted in Pitx3 expressing cells from embryonic day (E)13 onward. Supporting previous data, no significant changes could be observed in general dopamine (DA) marks, like Th, Pitx3 and Vmat2 at E14.5. However, in depth analysis by means of RNA-sequencing revealed that Lmx1b is important for the expression level of survival factors En1 and En2 and for the repression of mdDA subset mark Ahd2 during (late) development. Interestingly, the regulation of Ahd2 by Lmx1b was found to be Pitx3 independent, since Pitx3 levels were not altered in Lmx1b conditional knock-outs (cKO) and Ahd2 expression was also up-regulated in Lmx1b/Pitx3 double mutants compared to Pitx3 mutants. Further analysis of Lmx1b cKOs showed that post-mitotic deletion of Lmx1b additional leads to a loss of TH+ cells at 3 months age both in the VTA and SNc. Remarkably, different cell types were affected in the SNc and the VTA. While TH+AHD2+ cells were lost the SNc, TH+AHD2- neurons were affected in the VTA, reflected by a loss of Cck expression, indicating that Lmx1b is important for the survival of a sub-group of mdDA neurons.

scholarly journals HIV-2/SIV Vpx antagonises NF-𝜅B activation by targeting p65

2021 ◽  
Author(s):  
Douglas L Fink ◽  
James Cai ◽  
Matthew VX Whelan ◽  
Christopher Monit ◽  
Carlos Maaluquer de Motes ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Immune Responses ◽  
Gene Networks ◽  
Nuclear Translocation ◽  
Cell Types ◽  
Viral Pathogen ◽  
Mona Monkey ◽  
Molecular Patterns ◽  
Different Cell Types

The NF-𝜅B family of transcription factors and associated signalling pathways are abundant and ubiquitous in human immune responses. Activation of NF-𝜅B transcription factors by viral pathogen-associated molecular patterns, such as viral RNA and DNA, is fundamental to anti-viral innate immune defences and pro-inflammatory cytokine production that steers adaptive immune responses. Diverse non-viral stimuli, such as lipopolysaccharide and cytokines, also activate NF-𝜅B and the same anti-pathogen gene networks. Viruses adapted to human cells often encode multiple proteins aimed at varied NF-𝜅B pathway targeted to mitigate the anti-viral effects of NF-𝜅B-dependent host immunity. In this study we have demonstrated using numerous assays, in a number of different cell types, that plasmid-encoded or virus-delivered Simian Immunodeficiency Virus (SIV) accessory protein Vpx is a broad antagonist of NF-𝜅B signalling active against diverse innate NF-𝜅B agonists. Using targeted Vpx mutagenesis, we showed that this novel Vpx phenotype is independent of known Vpx cofactor DCAF1 and other cellular binding partners, including SAMHD1, STING and the HUSH complex. We found that Vpx co-immunoprecipitated with canonical NF-𝜅B transcription factor p65 and not NF-𝜅B transcription factor proteins p50 or p100, preventing nuclear translocation of p65, a novel mechanism of NF-𝜅B antagonism by lentiviruses. We found that broad antagonism of NF-𝜅B activation by Vpx was conserved across distantly related lentiviruses as well as for Vpr from SIV Mona monkey (SIVmon), which has Vpx-like SAMHD1-degradation activity.

scholarly journals TET2 binding to enhancers facilitates transcription factor recruitment in hematopoietic cells

2018 ◽  
Author(s):  
Kasper D. Rasmussen ◽  
Ivan Berest ◽  
Sandra Kessler ◽  
Koutarou Nishimura ◽  
Lucía Simón-Carrasco ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Expression Patterns ◽  
Cell Types ◽  
Open Chromatin ◽  
Disease Development ◽  
Hematopoietic Stem ◽  
Hematopoietic Malignancy ◽  
Genome Wide ◽  
Increased Risk ◽  
Different Cell Types

ABSTRACTThe epigenetic regulator TET2 is frequently mutated in hematological diseases. Mutations have been shown to arise in hematopoietic stem cells early in disease development, lead to altered DNA methylation landscapes and to an increased risk of hematopoietic malignancy. Here, we show by genome-wide mapping of TET2 binding sites in different cell types that TET2 localizes to regions of open chromatin and cell-type specific enhancers. We find that deletion of Tet2 in native hematopoiesis as well as fully transformed Acute Myeloid Leukemia (AML) results in changes in transcription factor (TF) activity within these regions, and we demonstrate that loss of TET2 leads to enzymatic activity-dependent attenuation of chromatin binding of the hematopoietic TF CDX4. Together, these findings demonstrate that TET2 activity shapes the local chromatin environment at enhancers to facilitate TF binding and provide a compelling example of how epigenetic dysregulation can affect gene expression patterns and drive disease development.

Study of the Molecular Architecture of Keratin Filaments by Electron Microscopy

1982 ◽  
Vol 40 ◽  
pp. 118-119
Author(s):  
U. Aebi ◽  
P. Rew ◽  
T.-T. Sun
Keyword(s):  
Electron Microscopy ◽  
Structural Organization ◽  
Cell Types ◽  
Structural Features ◽  
Molecular Architecture ◽  
The Past ◽  
Keratin Filaments ◽  
Different Types ◽  
10 Nm Filaments ◽  
Different Cell Types

Various types of intermediate-sized (10-nm) filaments have been found and described in many different cell types during the past few years. Despite the differences in the chemical composition among the different types of filaments, they all yield common structural features: they are usually up to several microns long and have a diameter of 7 to 10 nm; there is evidence that they are made of several 2 to 3.5 nm wide protofilaments which are helically wound around each other; the secondary structure of the polypeptides constituting the filaments is rich in ∞-helix. However a detailed description of their structural organization is lacking to date.

Processing and Characterization of Recombinant von Willebrand Factor Expressed in Different Cell Types Using a Vaccinia Virus Vector

1992 ◽  
Vol 67 (01) ◽  
pp. 154-160 ◽  
Author(s):  
P Meulien ◽  
M Nishino ◽  
C Mazurier ◽  
K Dott ◽  
G Piétu ◽  
...  
Keyword(s):  
Vaccinia Virus ◽  
Von Willebrand Factor ◽  
Human Fibroblasts ◽  
Active Form ◽  
Cell Types ◽  
Biologically Active ◽  
L Cells ◽  
Von Willebrand ◽  
Different Cell Types ◽  
Willebrand Factor

SummaryThe cloning of the cDNA encoding von Willebrand factor (vWF) has revealed that it is synthesized as a large precursor (pre-pro-vWF) molecule and it is now clear that the prosequence or vWAgll is responsible for the intracellular multimerization of vWF. We have cloned the complete vWF cDNA and expressed it using a recombinant vaccinia virus as vector. We have characterized the structure and function of the recombinant vWF (rvWF) secreted from five different cell types: baby hamster kidney (BHK), Chinese hamster ovary (CHO), human fibroblasts (143B), mouse fibroblasts (L) and primary embryonic chicken cells. Forty-eight hours after infection, the quantity of vWF antigen found in the cell supernatant varied from 3 to 12 U/dl depending on the cell type. By SDS-agarose gel electrophoresis, the percentage of high molecular weight forms of vWF varied from 39 to 49% relative to normal plasma for BHK, CHO, 143B and chicken cells but was less than 10% for L cells. In all cell types, the two anodic subbands of each multimer were missing. The two cathodic subbands were easily detected only in BHK and L cells. By SDS-PAGE of reduced samples, pro-vWF was present in similar quantity to the fully processed vWF subunit in L cells, present in moderate amounts in BHK and CHO and in very low amounts in 143B and chicken cells. rvWF from all cells bound to collagen and to platelets in the presence of ristocetin, the latter showing a high correlation between binding efficiency and degree of multimerization. rvWF from all cells was also shown to bind to purified FVIII and in this case binding appeared to be independent of the degree of multimerization. We conclude that whereas vWF is naturally synthesized only by endothelial cells and megakaryocytes, it can be expressed in a biologically active form from various other cell types.

Role of Transcriptional Read-Through in PRE Activity in Drosophila melanogaster

Acta Naturae ◽  
2016 ◽  
Vol 8 (2) ◽  
pp. 79-86 ◽  
Author(s):  
P. V. Elizar’ev ◽  
D. V. Lomaev ◽  
D. A. Chetverina ◽  
P. G. Georgiev ◽  
M. M. Erokhin
Keyword(s):  
Dna Sequences ◽  
Cell Types ◽  
Transcription Terminator ◽  
Response Elements ◽  
Polycomb Response Elements ◽  
The Individual ◽  
Multicellular Organisms ◽  
Different Cell Types ◽  
Main Factor

Maintenance of the individual patterns of gene expression in different cell types is required for the differentiation and development of multicellular organisms. Expression of many genes is controlled by Polycomb (PcG) and Trithorax (TrxG) group proteins that act through association with chromatin. PcG/TrxG are assembled on the DNA sequences termed PREs (Polycomb Response Elements), the activity of which can be modulated and switched from repression to activation. In this study, we analyzed the influence of transcriptional read-through on PRE activity switch mediated by the yeast activator GAL4. We show that a transcription terminator inserted between the promoter and PRE doesnt prevent switching of PRE activity from repression to activation. We demonstrate that, independently of PRE orientation, high levels of transcription fail to dislodge PcG/TrxG proteins from PRE in the absence of a terminator. Thus, transcription is not the main factor required for PRE activity switch.

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