scholarly journals Transcription enhancer factor 1 interacts with a basic helix-loop-helix zipper protein, Max, for positive regulation of cardiac alpha-myosin heavy-chain gene expression.

1997 ◽  
Vol 17 (7) ◽  
pp. 3924-3936 ◽  
Author(s):  
M P Gupta ◽  
C S Amin ◽  
M Gupta ◽  
N Hay ◽  
R Zak
Keyword(s):  
Myosin Heavy Chain ◽  
Reporter Gene ◽  
Heavy Chain ◽  
Troponin T ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
E Box ◽  
Two Factors ◽  
Transcription Enhancer ◽  
Enhancer Factor

The M-CAT binding factor transcription enhancer factor 1 (TEF-1) has been implicated in the regulation of several cardiac and skeletal muscle genes. Previously, we identified an E-box-M-CAT hybrid (EM) motif that is responsible for the basal and cyclic AMP-inducible expression of the rat cardiac alpha-myosin heavy chain (alpha-MHC) gene in cardiac myocytes. In this study, we report that two factors, TEF-1 and a basic helix-loop-helix leucine zipper protein, Max, bind to the alpha-MHC EM motif. We also found that Max was a part of the cardiac troponin T M-CAT-TEF-1 complex even when the DNA template did not contain an apparent E-box binding site. In the protein-protein interaction assay, a stable association of Max with TEF-1 was observed when glutathione S-transferase (GST)-TEF-1 or GST-Max was used to pull down in vitro-translated Max or TEF-1, respectively. In addition, Max was coimmunoprecipitated with TEF-1, thus documenting an in vivo TEF-1-Max interaction. In the transient transcription assay, overexpression of either Max or TEF-1 resulted a mild activation of the alpha-MHC-chloramphenicol acetyltransferase (CAT) reporter gene at lower concentrations and repression of this gene at higher concentrations. However, when Max and TEF-1 expression plasmids were transfected together, the repression mediated by a single expression plasmid was alleviated and a three- to fourfold transactivation of the alpha-MHC-CAT reporter gene was observed. This effect was abolished once the EM motif in the promoter-reporter construct was mutated, thus suggesting that the synergistic transactivation function of the TEF-1-Max heterotypic complex is mediated through binding of the complex to the EM motif. These results demonstrate a novel association between Max and TEF-1 and indicate a positive cooperation between these two factors in alpha-MHC gene regulation.

scholarly journals Displacement of an E-box-binding repressor by basic helix-loop-helix proteins: implications for B-cell specificity of the immunoglobulin heavy-chain enhancer.

1994 ◽  
Vol 14 (9) ◽  
pp. 6153-6163 ◽  
Author(s):  
T Genetta ◽  
D Ruezinsky ◽  
T Kadesch
Keyword(s):  
B Cells ◽  
B Cell ◽  
Heavy Chain ◽  
Zinc Finger Protein ◽  
Immunoglobulin Heavy Chain ◽  
Bhlh Protein ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
E Box ◽  
Bhlh Proteins

The activity of the immunoglobulin heavy-chain (IgH) enhancer is restricted to B cells, although it binds both B-cell-restricted and ubiquitous transcription factors. Activation of the enhancer in non-B cells upon overexpression of the basic helix-loop-helix (bHLH) protein E2A appears to be mediated not only by the binding of E2A to its cognate E box but also by the resulting displacement of a repressor from that same site. We have identified a "two-handed" zinc finger protein, denoted ZEB, the DNA-binding specificity of which mimics that of the cellular repressor. By employing a derivative E box that binds ZEB but not E2A, we have shown that the repressor is active in B cells and the IgH enhancer is silenced in the absence of binding competition by bHLH proteins. Hence, we propose that a necessary prerequisite of enhancer activity is the B-cell-specific displacement of a ZEB-like repressor by bHLH proteins.

Effect of unloading on type I myosin heavy chain gene regulation in rat soleus muscle

2005 ◽  
Vol 98 (4) ◽  
pp. 1185-1194 ◽  
Author(s):  
Julia M. Giger ◽  
Fadia Haddad ◽  
Anqi X. Qin ◽  
Ming Zeng ◽  
Kenneth M. Baldwin
Keyword(s):  
Myosin Heavy Chain ◽  
Soleus Muscle ◽  
Heavy Chain ◽  
Regulatory Elements ◽  
Hindlimb Suspension ◽  
Type I ◽  
Transcriptional Enhancer ◽  
Western Blots ◽  
E Box ◽  
Enhancer Factor

Slow-twitch soleus, a weight-bearing hindlimb muscle, predominantly expresses the type I myosin heavy chain (MHC) isoform. However, under unloading conditions, a transition in MHC expression occurs from slow type I toward the fast-type isoforms. Transcriptional processes are believed to be involved in this adaptation. To test the hypothesis that the downregulation of MHC1 in soleus muscle following unloading is controlled through cis element(s) in the proximal region of the promoter, the MHC1 promoter was injected into soleus muscles of control rats and those subjected to 7 days of hindlimb suspension. Mutation analyses of six putative regulatory elements within the −408-bp region demonstrated that three elements, an A/T-rich, the proximal muscle-type CAT (βe3), and an E-box (−63 bp), play an important role in the basal level of MHC1 gene activity in the control soleus and function as unloading-responsive elements. Gel mobility shift assays revealed a diminished level of complex formation of the βe3 and E-box probes with nuclear extract from hindlimb suspension soleus compared with control soleus. Supershift assays indicated that transcriptional enhancer factor 1 and myogenin factors bind the βe3 and E-box elements, respectively, in the control soleus. Western blots showed that the relative concentrations of the transcriptional enhancer factor 1 and myogenin factors were significantly attenuated in the unloaded soleus compared with the control muscle. We conclude that the downregulation of MHC1 in response to unloading is due, in part, to a significant decrease in the concentration of these transcription factors available for binding the positive regulatory elements.

Displacement of an E-box-binding repressor by basic helix-loop-helix proteins: implications for B-cell specificity of the immunoglobulin heavy-chain enhancer

1994 ◽  
Vol 14 (9) ◽  
pp. 6153-6163
Author(s):  
T Genetta ◽  
D Ruezinsky ◽  
T Kadesch
Keyword(s):  
B Cells ◽  
B Cell ◽  
Heavy Chain ◽  
Zinc Finger Protein ◽  
Immunoglobulin Heavy Chain ◽  
Bhlh Protein ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
E Box ◽  
Bhlh Proteins

The activity of the immunoglobulin heavy-chain (IgH) enhancer is restricted to B cells, although it binds both B-cell-restricted and ubiquitous transcription factors. Activation of the enhancer in non-B cells upon overexpression of the basic helix-loop-helix (bHLH) protein E2A appears to be mediated not only by the binding of E2A to its cognate E box but also by the resulting displacement of a repressor from that same site. We have identified a "two-handed" zinc finger protein, denoted ZEB, the DNA-binding specificity of which mimics that of the cellular repressor. By employing a derivative E box that binds ZEB but not E2A, we have shown that the repressor is active in B cells and the IgH enhancer is silenced in the absence of binding competition by bHLH proteins. Hence, we propose that a necessary prerequisite of enhancer activity is the B-cell-specific displacement of a ZEB-like repressor by bHLH proteins.

scholarly journals Selective utilization of basic helix-loop-helix-leucine zipper proteins at the immunoglobulin heavy-chain enhancer.

1997 ◽  
Vol 17 (1) ◽  
pp. 18-23 ◽  
Author(s):  
R S Carter ◽  
P Ordentlich ◽  
T Kadesch
Keyword(s):  
Heavy Chain ◽  
Leucine Zipper ◽  
Physiological Role ◽  
Immunoglobulin Heavy Chain ◽  
Dominant Negative ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
E Box ◽  
Derivatives Of

The microE3 E box within the immunoglobulin heavy-chain (IgH) enhancer binds several proteins of the basic helix-loop-helix-leucine zipper (bHLHzip) class, including TFE3, USF1, and Max. Both TFE3 and USF have been described as transcriptional activators, and so we investigated their possible roles in activating the IgH enhancer in vivo. Although TFE3 activated various enhancer-based reporters, both USF1 and Max effectively inhibited transcription. Inhibition by USF correlated with the lack of a strong activation domain and was the result of the protein neutralizing the microE3 site. The effects of dominant-negative derivatives of TFE3 and USF1 confirmed that TFE3, or a TFE3-like protein, is the primary cellular bHLHzip protein that activates the IgH enhancer. In addition to providing a physiological role for TFE3, our results call into question the traditional view of USF1 as an obligate transcriptional activator.

Transcriptional regulation of the type I myosin heavy chain promoter in inactive rat soleus

2002 ◽  
Vol 282 (3) ◽  
pp. C528-C537 ◽  
Author(s):  
K. A. Huey ◽  
R. R. Roy ◽  
F. Haddad ◽  
V. R. Edgerton ◽  
K. M. Baldwin
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Gene Promoter ◽  
Type I ◽  
Mobility Shift ◽  
Cis Acting ◽  
Gel Mobility Shift ◽  
Transcription Enhancer ◽  
Enhancer Factor

Chronic muscle inactivity with spinal cord isolation (SI) decreases expression of slow type I myosin heavy chain (MHC) while increasing expression of the faster MHC isoforms, primarily IIx. The purpose of this study was to determine whether type I MHC downregulation in the soleus muscle of SI rats is regulated transcriptionally and to identify cis-acting elements or regions of the rat type I MHC gene promoter involved in this response. One week of SI significantly decreased in vivo activity of the −3500-, −408-, −299-, −215-, and −171-bp type I MHC promoters. The activity of all tested deletions of the type I MHC promoter, relative to the human skeletal α-actin promoter, were significantly reduced in the SI soleus, except activity of the −171-bp promoter, which increased. Mutation of the βe3 element (−214/−190 bp) in the −215- and −408-bp promoters and deletion of this element (−171-bp promoter) attenuated type I downregulation with SI. Gel mobility shift assays demonstrated a decrease in transcription enhancer factor-1 binding to the βe3 element with SI, despite an increase in total binding to this region. These results demonstrate that type I MHC downregulation with SI is transcriptionally regulated and suggest that interactions between transcription enhancer factor-1 and the βe3 element are likely involved in this response.

Scleraxis: a basic helix-loop-helix protein that prefigures skeletal formation during mouse embryogenesis

Development ◽  
1995 ◽  
Vol 121 (4) ◽  
pp. 1099-1110 ◽  
Author(s):  
P. Cserjesi ◽  
D. Brown ◽  
K.L. Ligon ◽  
G.E. Lyons ◽  
N.G. Copeland ◽  
...  
Keyword(s):  
Connective Tissue ◽  
Expression Pattern ◽  
Consensus Sequence ◽  
Cell Types ◽  
Cell Type ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
E Box ◽  
Cell Type Specific ◽  
Bhlh Proteins

Members of the basic helix-loop-helix (bHLH) family of transcription factors have been shown to regulate growth and differentiation of numerous cell types. Cell-type-specific bHLH proteins typically form heterodimers with ubiquitous bHLH proteins, such as E12, and bind a DNA consensus sequence known as an E-box. We used the yeast two-hybrid system to screen mouse embryo cDNA libraries for cDNAs encoding novel cell-type-specific bHLH proteins that dimerize with E12. One of the cDNAs isolated encoded a novel bHLH protein, called scleraxis. During mouse embryogenesis, scleraxis transcripts were first detected between day 9.5 and 10.5 post coitum (p.c.) in the sclerotome of the somites and in mesenchymal cells in the body wall and limb buds. Subsequently, scleraxis was expressed at high levels within mesenchymal precursors of the axial and appendicular skeleton and in cranial mesenchyme in advance of chondrogenesis; its expression pattern in these cell types foreshadowed the developing skeleton. Prior to formation of the embryonic cartilaginous skeleton, scleraxis expression declined to low levels. As development proceeded, high levels of scleraxis expression became restricted to regions where cartilage and connective tissue formation take place. Scleraxis bound the E-box consensus sequence as a heterodimer with E12 and activated transcription of a reporter gene linked to its DNA-binding site. The expression pattern, DNA-binding properties and transcriptional activity of scleraxis suggest that it is a regulator of gene expression within mesenchymal cell lineages that give rise to cartilage and connective tissue.

scholarly journals mTFE3, an X-linked transcriptional activator containing basic helix-loop-helix and zipper domains, utilizes the zipper to stabilize both DNA binding and multimerization.

1992 ◽  
Vol 12 (2) ◽  
pp. 817-827 ◽  
Author(s):  
C Roman ◽  
A G Matera ◽  
C Cooper ◽  
S Artandi ◽  
S Blain ◽  
...  
Keyword(s):  
Dna Binding ◽  
Heavy Chain ◽  
Leucine Zipper ◽  
Immunoglobulin Heavy Chain ◽  
Functional Roles ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
The Individual ◽  
Bhlh Proteins ◽  
High Degree

Southwestern (DNA-protein) screening of a murine L-cell cDNA library by using a probe for the microE3 site in the immunoglobulin heavy-chain enhancer yielded a clone, mTFE3, which is a member of the subset of basic helix-loop-helix (BHLH) proteins that also contain a leucine zipper (ZIP). Since the individual contribution of these domains is not well understood for proteins which contain them both, mutational analyses were performed to assess the functional roles of the HLH and ZIP regions for DNA binding and multimerization. The HLH region is stringently required for DNA binding but not for multimerization. The ZIP region is not stringently required for binding or multimerization, but stabilizes both multimer formation and DNA binding. A high degree of conservation at both the amino acid and nucleotide levels between the human transcription factor TFE3 and mTFE3 suggests that mTFE3 is the murine homolog of human TFE3. By using fluorescent in situ hybridization, mTFE3 was mapped to mouse chromosome X in band A2, which is just below the centromere. We show that in addition to the immunoglobulin heavy-chain microE3 site, mTFE3 binds to transcriptional elements important for lymphoid-specific, muscle-specific, and ubiquitously expressed genes. Binding of mTFE3 to DNA induces DNA bending.

Sign in / Sign up

Export Citation Format

Share Document