scholarly journals The MYCL and MXD1 transcription factors regulate the fitness of murine dendritic cells

2020 ◽  
Vol 117 (9) ◽  
pp. 4885-4893 ◽  
Author(s):  
David A. Anderson ◽  
Theresa L. Murphy ◽  
Robert N. Eisenman ◽  
Kenneth M. Murphy
Keyword(s):  
Transcription Factors ◽  
Cell Subset ◽  
Underlying Mechanism ◽  
Regulation Of Transcription ◽  
Dendritic Cell Subset ◽  
Transcriptional Program ◽  
Specific Expression ◽  
Transcriptional Signature ◽  
Helix Loop Helix

We previously found that MYCL is required by aBatf3-dependent classical dendritic cell subset (cDC1) for optimal CD8 T cell priming, but the underlying mechanism has remained unclear. The MAX-binding proteins encompass a family of transcription factors with overlapping DNA-binding specificities, conferred by a C-terminal basic helix-loop-helix domain, which mediates heterodimerization. Thus, regulation of transcription by these factors is dependent on divergent N-terminal domains. The MYC family, including MYCL, has actions that are reciprocal to the MXD family, which is mediated through the recruitment of higher-order activator and repressor complexes, respectively. As potent proto-oncogenes, models of MYC family function have been largely derived from their activity at supraphysiological levels in tumor cell lines. MYC and MYCN have been studied extensively, but empirical analysis of MYCL function had been limited due to highly restricted, lineage-specific expression in vivo. Here we observed thatMyclis expressed in immature cDC1s but repressed on maturation, concomitant withMxd1induction in mature cDC1s. We hypothesized that MYCL and MXD1 regulate a shared, but reciprocal, transcriptional program during cDC1 maturation. In agreement, immature cDC1s inMycl−/−-deficient mice exhibited reduced expression of genes that regulate core biosynthetic processes. Mature cDC1s fromMxd1−/−mice exhibited impaired ability to inhibit the transcriptional signature otherwise supported by MYCL. The present study reveals LMYC and MXD1 as regulators of a transcriptional program that is modulated during the maturation ofBatf3-dependent cDC1s.

scholarly journals Single molecule tracking of Ace1p in Saccharomyces cerevisiae defines a characteristic residence time for non-specific interactions of transcription factors with chromatin

2016 ◽  
Vol 44 (21) ◽  
pp. e160-e160 ◽  
Author(s):  
David A Ball ◽  
Gunjan D Mehta ◽  
Ronit Salomon-Kent ◽  
Davide Mazza ◽  
Tatsuya Morisaki ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Residence Time ◽  
Single Molecule ◽  
Specific Binding ◽  
Underlying Mechanism ◽  
Specific Interactions ◽  
Single Molecule Tracking ◽  
Reliable Performance ◽  
Transient Interactions

Abstract In vivo single molecule tracking has recently developed into a powerful technique for measuring and understanding the transient interactions of transcription factors (TF) with their chromatin response elements. However, this method still lacks a solid foundation for distinguishing between specific and non-specific interactions. To address this issue, we took advantage of the power of molecular genetics of yeast. Yeast TF Ace1p has only five specific sites in the genome and thus serves as a benchmark to distinguish specific from non-specific binding. Here, we show that the estimated residence time of the short-residence molecules is essentially the same for Hht1p, Ace1p and Hsf1p, equaling 0.12–0.32 s. These three DNA-binding proteins are very different in their structure, function and intracellular concentration. This suggests that (i) short-residence molecules are bound to DNA non-specifically, and (ii) that non-specific binding shares common characteristics between vastly different DNA-bound proteins and thus may have a common underlying mechanism. We develop new and robust procedure for evaluation of adverse effects of labeling, and new quantitative analysis procedures that significantly improve residence time measurements by accounting for fluorophore blinking. Our results provide a framework for the reliable performance and analysis of single molecule TF experiments in yeast.

scholarly journals Regulation of Transcription Factors and Repression of Sp1 by Prolactin Signaling Through the Short Isoform of Its Cognate Receptor

Endocrinology ◽  
2009 ◽  
Vol 150 (7) ◽  
pp. 3327-3335 ◽  
Author(s):  
Y. Sangeeta Devi ◽  
Aurora Shehu ◽  
Carlos Stocco ◽  
Julia Halperin ◽  
Jamie Le ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Signaling Pathway ◽  
Short Form ◽  
Binding Activity ◽  
In Vivo Model ◽  
Regulation Of Transcription ◽  
Signaling Mechanism ◽  
Dna Binding Activity ◽  
And Function

Prolactin (PRL) affects the development and function of the reproductive system by binding to two types of receptors, which differ by the size of their intracellular domain in rodents. Whereas the signaling pathway through the long form of the receptor (PRL-RL) is well characterized, signaling through the short form (PRL-RS) remains obscure. In this investigation, we examined transcription factors regulated by PRL in the ovary and decidua of mice expressing only PRL-RS in a PRL receptor null background. These mice provide a powerful in vivo model to study the selective signaling mechanism of PRL through PRL-RS independent of PRL-RL. We also examined the regulation of transcription factors in ovarian and uterine cell lines stably transfected with PRL-RS or PRL-RL. We focused our investigation on transcription factors similarly regulated in both these tissues and clearly established that signaling through PRL-RS does not activate the JaK/Stat in vivo but leads to severe down-regulation of Sp1 expression, DNA binding activity, and nuclear localization, events that appear to involve the calmodulin-dependent protein kinase pathway. Our in vivo and in culture data demonstrate that the PRL-RS activates a signaling pathway distinct from that of the PRL-RL.

scholarly journals The CD8+ Dendritic Cell Subset Selectively Endocytoses Dying Cells in Culture and In Vivo

2002 ◽  
Vol 195 (10) ◽  
pp. 1289-1302 ◽  
Author(s):  
Tomonori Iyoda ◽  
Susumu Shimoyama ◽  
Kang Liu ◽  
Yoshiki Omatsu ◽  
Yuji Akiyama ◽  
...  
Keyword(s):  
T Cells ◽  
Cd8 T Cells ◽  
Ex Vivo ◽  
Osmotic Shock ◽  
Cell Subset ◽  
Fluorescent Labeling ◽  
Dendritic Cell Subset ◽  
Dying Cells

Dendritic cells (DCs) are able in tissue culture to phagocytose and present antigens derived from infected, malignant, and allogeneic cells. Here we show directly that DCs in situ take up these types of cells after fluorescent labeling with carboxyfluorescein succinimidyl ester (CFSE) and injection into mice. The injected cells include syngeneic splenocytes and tumor cell lines, induced to undergo apoptosis ex vivo by exposure to osmotic shock, and allogeneic B cells killed by NK cells in situ. The CFSE-labeled cells in each case are actively endocytosed by DCs in vivo, but only the CD8+ subset. After uptake, all of the phagocytic CD8+ DCs can form major histocompatibility complex class II–peptide complexes, as detected with a monoclonal antibody specific for these complexes. The CD8+ DCs also selectively present cell-associated antigens to both CD4+ and CD8+ T cells. Similar events take place with cultured DCs; CD8+ DCs again selectively take up and present dying cells. In contrast, both CD8+ and CD8− DCs phagocytose latex particles in culture, and both DC subsets present soluble ovalbumin captured in vivo. Therefore CD8+ DCs are specialized to capture dying cells, and this helps to explain their selective ability to cross present cellular antigens to both CD4+ and CD8+ T cells.

New Approaches for Mapping Epigenome Dynamics

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. SCI-21-SCI-21
Author(s):  
Steven Henikoff
Keyword(s):  
Transcription Factors ◽  
Rna Polymerase Ii ◽  
Conflicts Of Interest ◽  
Regulation Of Transcription ◽  
Base Pairs ◽  
Simple Method ◽  
Genome Wide ◽  
Resolution Mapping

Abstract The protein complexes that package our genomes must be mobilized for active processes to occur, including replication and transcription, but until recently we have only had a static, low resolution view of the "epigenome". Genomes are packaged into nucleosomes, octamers of four core histones wrapped by 147 base pairs of DNA. Nucleosomes present obstacles to transcription, which over genes is the RNA Polymerase II (RNAPII) complex, and one current challenge is to understand what happens to a nucleosome when RNAPII transcribes through the DNA that it occupies. We study this process by developing methods for following nucleosomes as they are evicted and replaced. Among the factors that we have implicated in the process is torsional stress, which we can now measure genome-wide. RNAPII movement can unwrap nucleosomes and thus destabilize them, causing them to be occasionally evicted and replaced. Interestingly, we find that destabilization of nucleosomes during transcription is enhanced by anthracycline compounds, widely used chemotherapeutic drugs that intercalate between DNA base pairs, thus suggesting a new mechanism for cell killing during chemotherapy. We are also interested in what happens to RNAPII during its encounter with a nucleosomes. In vitro, RNAPII cannot transcribe completely through a nucleosome, but rather stalls as it tries to unwrap the DNA from around the core. We have been studying this process in vivo, and have developed a simple method for precisely mapping RNAPII genome-wide. We have used this method to show exactly where RNAPII stalls as it unwraps a nucleosome in vivo, surprisingly in a different place in vivo from where it stalls in vitro. We also have discovered that a variant histone, H2A.Z, which is found in essentially all eukaryotes, helps to reduce the nucleosome barrier to transcription, and in this way may modulate transcription. Other protein components of the epigenome involved in dynamic processes are nucleosome remodelers, which use the energy of ATP to slide or even evict nucleosomes from DNA. Some remodelers help RNAPII get started and others help it overcome the nucleosome barrier to transcription, and by mapping them at base-pair resolution, we can gain insight into how they act. We have also applied our high-resolution mapping tools to transcription factors, which bind DNA at specific sites to regulate transcription and other processes. Our ability to achieve high spatial and temporal resolution mapping of the binding and action of nucleosomes, transcription factors, remodelers and RNAPII provides us with a detailed picture of epigenome dynamics. By using these tools we are beginning to understand how DNA sequence and conformation are recognized for regulation of transcription and other epigenomic processes. Disclosures No relevant conflicts of interest to declare.

scholarly journals SCL Assembles a Multifactorial Complex That Determines Glycophorin A Expression

2004 ◽  
Vol 24 (4) ◽  
pp. 1439-1452 ◽  
Author(s):  
Rachid Lahlil ◽  
Eric Lécuyer ◽  
Sabine Herblot ◽  
Trang Hoang
Keyword(s):  
Transcription Factors ◽  
Hematopoietic Cells ◽  
Inhibitory Effect ◽  
Erythroid Cell ◽  
Glycophorin A ◽  
Protein Activity ◽  
Protein Levels ◽  
Helix Loop Helix

ABSTRACT SCL/TAL1 is a hematopoietic-specific transcription factor of the basic helix-loop-helix (bHLH) family that is essential for erythropoiesis. Here we identify the erythroid cell-specific glycophorin A gene (GPA) as a target of SCL in primary hematopoietic cells and show that SCL occupies the GPA locus in vivo. GPA promoter activation is dependent on the assembly of a multifactorial complex containing SCL as well as ubiquitous (E47, Sp1, and Ldb1) and tissue-specific (LMO2 and GATA-1) transcription factors. In addition, our observations suggest functional specialization within this complex, as SCL provides its HLH protein interaction motif, GATA-1 exerts a DNA-tethering function through its binding to a critical GATA element in the GPA promoter, and E47 requires its N-terminal moiety (most likely entailing a transactivation function). Finally, endogenous GPA expression is disrupted in hematopoietic cells through the dominant-inhibitory effect of a truncated form of E47 (E47-bHLH) on E-protein activity or of FOG (Friend of GATA) on GATA activity or when LMO2 or Ldb-1 protein levels are decreased. Together, these observations reveal the functional complementarities of transcription factors within the SCL complex and the essential role of SCL as a nucleation factor within a higher-order complex required to activate gene GPA expression.

scholarly journals Homologous BHLH transcription factors induce distinct deformations of torsionally-stressed DNA: a potential transcription regulation mechanism.

2022 ◽  
Author(s):  
Johanna Hörberg ◽  
Kevin Moreau ◽  
Anna Reymer
Keyword(s):  
Transcription Factors ◽  
Specific Binding ◽  
Torsional Rigidity ◽  
Regulation Mechanism ◽  
Regulation Of Transcription ◽  
Torsional Stress ◽  
Bioinformatics Analyses ◽  
Helix Loop Helix ◽  
Dynamics Simulations ◽  
The Impact

Changing torsional restraints on DNA is essential for the regulation of transcription. Torsional stress, introduced by RNA polymerase, can propagate along chromatin facilitating topological transitions and modulating the specific binding of transcription factors (TFs) to DNA. Despite the importance, the mechanistic details on how torsional stress impacts the TFs-DNA complexation remain scarce. Herein we address the impact of torsional stress on DNA complexation with homologous human basic-helix-loop-helix (BHLH) hetero- and homodimers: MycMax, MadMax, and MaxMax. The three TF dimers exhibit specificity towards the same DNA consensus sequences, the E-box response element, while regulating different transcriptional pathways. Using microseconds-long atomistic molecular dynamics simulations together with the torsional restraint that controls DNA total helical twist, we gradually over- and underwind naked and complexed DNA to a maximum of ±5°/b.p. step. We observe that the binding of the BHLH dimers results in a similar increase in DNA torsional rigidity. However, under torsional stress the BHLH dimers induce distinct DNA deformations, characterised by changes in DNA grooves geometry and a significant asymmetric DNA bending. Supported by bioinformatics analyses, our data suggest that torsional stress may contribute to the execution of differential transcriptional programs of the homologous TFs by modulating their collaborative interactions.

scholarly journals Achieving dendritic cell subset-specific targeting in vivo by site-directed conjugation of targeting antibodies to nanocarriers

2021 ◽  
Author(s):  
Johanna Simon ◽  
Michael Fichter ◽  
Gabor Kuhn ◽  
Maxmimilian Brueckner ◽  
Cinja Kappel ◽  
...  
Keyword(s):  
Surface Functionalization ◽  
Targeted Delivery ◽  
Immune Cell ◽  
Specific Interaction ◽  
Cell Subset ◽  
Target Cells ◽  
Dendritic Cell Subset ◽  
Specific Targeting ◽  
Body Distribution

The major challenge of nanocarrier-based anti-cancer vaccination approaches is the targeted delivery of antigens and immunostimulatory agents to cells of interest, such as specific subtypes of dendritic cells (DCs), in order to induce robust antigen-specific anti-tumor responses. An undirected cell and body distribution of nanocarriers can lead to unwanted delivery to other immune cell types like macrophages reducing the vaccine efficacy. An often-used approach to overcome this issue is the surface functionalization of nanocarriers with targeting moieties, such as antibodies, mediating cell type-specific interaction. Numerous studies could successfully prove the targeting efficiency of antibody-conjugated carrier systems in vitro, however, most of them failed when targeting DCs in vivo that is partly due to cells of the reticuloendothelial system unspecifically clearing nanocarriers from the blood stream via Fc receptor ligation. Therefore, this study shows a surface functionalization strategy to site-specifically attach antibodies in an orientated direction onto the nanocarrier surface. Different DC-targeting antibodies, such as anti-CD11c, anti-CLEC9A, anti-DEC205 and anti-XCR1, were conjugated to the nanocarrier surface at their Fc domains. Anti-mouse CD11c antibody-conjugated nanocarriers specifically accumulated in the targeted organ (spleen) over time. Additionally, antibodies against CD11c and CLEC9A proved to specifically direct nanocarriers to the targeted DC subtype, conventional DCs type 1. In conclusion, site-directed antibody conjugation to nanocarriers is essential in order to avoid unspecific uptake by non-target cells while achieving antibody-specific targeting of DC subsets. This novel conjugation technique paves the way for the development of antibody-functionalized nanocarriers for DC-based vaccination approaches in the field of cancer immunotherapy.

scholarly journals PU.1/Pip and Basic Helix Loop Helix Zipper Transcription Factors Interact With Binding Sites in the CD20 Promoter to Help Confer Lineage- and Stage-Specific Expression of CD20 in B Lymphocytes

Blood ◽  
1997 ◽  
Vol 90 (10) ◽  
pp. 3984-3995 ◽  
Author(s):  
Andreas Himmelmann ◽  
Agostino Riva ◽  
Gaye Lynn Wilson ◽  
Brian P. Lucas ◽  
Claire Thevenin ◽  
...  
Keyword(s):  
B Cell ◽  
Plasma Cells ◽  
Expression Vectors ◽  
Specific Gene ◽  
Cell Stage ◽  
Specific Expression ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
E Box

Abstract CD20 is a B-lineage–specific gene expressed at the pre–B-cell stage of B-cell development that disappears on differentiation to plasma cells. As such, it serves as an excellent paradigm for the study of lineage and developmental stage-specific gene expression. Using in vivo footprinting we identified two sites in the promoter at −45 and −160 that were occupied only in CD20+ B cells. The −45 site is an E box that binds basic helix-loop-helix-zipper proteins whereas the −160 site is a composite PU.1 and Pip binding site. Transfection studies with reporter constructs and various expression vectors verified the importance of these sites. The composite PU.1 and Pip site likely accounts for both lineage and stage-specific expression of CD20 whereas the CD20 E box binding proteins enhance overall promoter activity and may link the promoter to a distant enhancer.

Sign in / Sign up

Export Citation Format

Share Document