Triiodothyronine-mediated myosin heavy chain gene transcription in the heart

2003 ◽  
Vol 284 (6) ◽  
pp. H2255-H2262 ◽  
Author(s):  
Sara Danzi ◽  
Kaie Ojamaa ◽  
Irwin Klein
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Time Course ◽  
Molecular Mechanisms ◽  
Chain Gene ◽  
Regulation Of Transcription ◽  
Mhc Genes ◽  
Coordinated Regulation ◽  
Relationship Of

We developed an RT-PCR assay to study both the time course and the mechanism for the triiodothyronine (T3)-induced transcription of the α- and β-myosin heavy chain (MHC) genes in vivo on the basis of the quantity of specific heterogeneous nuclear RNA (hnRNA). The temporal relationship of changes in transcriptional activity to the amount of α-MHC mRNA and the coordinated regulation of transcription of more than one gene in response to T3 are demonstrated here for the first time. Quantitation of α-MHC hnRNA demonstrated that T3 induced α-MHC transcription in hypothyroid rats within 30 min of a single injection of T3 (0.5 μg/100 g body wt). Maximal transcription rates (135% ± 15.8 of euthyroid values) occurred 6 h after injection and subsequently declined in parallel with serum T3 levels. The transcription of β-MHC was reduced to 86% of peak hypothyroid levels 6 h after a single T3injection and reached a nadir of 59% of hypothyroid levels at 36 h. Analysis of the time course of T3-mediated induction of α-MHC hnRNA and repression of β-MHC hnRNA indicates that separate molecular mechanisms are involved in the coordinated regulation of these genes.

Transcriptional regulation of the type I myosin heavy chain gene in denervated rat soleus

2003 ◽  
Vol 284 (3) ◽  
pp. C738-C748 ◽  
Author(s):  
K. A. Huey ◽  
F. Haddad ◽  
A. X. Qin ◽  
K. M. Baldwin
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Molecular Mechanisms ◽  
Mutational Analysis ◽  
Chain Gene ◽  
Type I ◽  
Slow Type ◽  
Actin Promoter ◽  
Mrna Analysis

Denervation (DEN) of rat soleus is associated with a decreased expression of slow type I myosin heavy chain (MHC) and an increased expression of the faster MHC isoforms. The molecular mechanisms behind these shifts remain unclear. We first investigated endogenous transcriptional activity of the type I MHC gene in normal and denervated soleus muscles via pre-mRNA analysis. Our results suggest that the type I MHC gene is regulated via transcriptional processes in the denervated soleus. Deletion and mutational analysis of the rat type I MHC promoter was then used to identify cis elements or regions of the promoter involved in this response. DEN significantly decreased in vivo activity of the −3,500, −2,500, −914, −408, −299, and −215 bp type I MHC promoters, relative to the α-skeletal actin promoter. In contrast, normalized −171 promoter activity was unchanged. Mutation of the βe3 element (−214/−190) in the −215 promoter and deletion of this element (−171 promoter) blunted type I downregulation with DEN. In contrast, βe3 mutation in the −408 promoters was not effective in attenuating the DEN response, suggesting the existence of additional DEN-responsive sites between −408 and −215. Western blotting and gel mobility supershift assays demonstrated decreased expression and DNA binding of transcription enhancer factor 1 (TEF-1) with DEN, suggesting that this decrease may contribute to type I MHC downregulation in denervated muscle.

Differential regulation by thyroid hormones of myosin heavy chain α and β mRNAs in the rat ventricular myocardium

1989 ◽  
Vol 122 (1) ◽  
pp. 193-200 ◽  
Author(s):  
N. K. Green ◽  
J. A. Franklyn ◽  
J. A. O. Ahlquist ◽  
M. D. Gammage ◽  
M. C. Sheppard
Keyword(s):  
Myosin Heavy Chain ◽  
Cardiac Myocytes ◽  
Heavy Chain ◽  
Ventricular Myocardium ◽  
Mhc Genes ◽  
Specific Effects ◽  
Dependent Inhibition ◽  
Dose Dependent

ABSTRACT The effect of tri-iodothyronine (T3) treatment on myocardial levels of α and β myosin heavy chain (MHC) mRNAs in the rat was defined in vivo and in vitro. Dose–response experiments were performed in intact hypothyroid and euthyroid rats; in addition, studies in vitro examined the effect of T3 on MHC mRNAs in neonatal cardiac myocytes in primary culture. Specific α and β MHC mRNAs were determined by Northern blot and dot hybridization to oligonucleotide probes complementary to the 3′ untranslated regions of the MHC genes. An increase in myocardial β MHC mRNA was demonstrated in hypothyroidism, accompanied by a reduction in α MHC mRNA. Marked differences in the sensitivity of α and β MHC mRNAs to T3 replacement were found; a dose-dependent increase in α mRNA was evident at 6 h after T3 treatment, in the absence of consistent effects on β mRNA, whereas 72 h after T3 replacement was commenced, stimulatory effects of T3 on α MHC mRNA, evident at all doses, were accompanied by a dose-dependent inhibition of β MHC mRNA. No effect of thyroid status on actin mRNA was found, indicating the specificity of MHC gene regulation. T3 treatment of cardiac myocytes in vitro exerted similar actions on MHC mRNAs to those found in vivo, with a more marked influence on α than β MHC mRNA. These studies of the action of T3 in vivo and in vitro have thus demonstrated specific effects of T3 on pretranslational regulation of the α and β MHC genes, influences which differ not only in terms of stimulation or inhibition, but also in magnitude of effect. Journal of Endocrinology (1989) 122, 193–200

Molecular characterization of a developmentally regulated porcine skeletal myosin heavy chain gene and its 5′ regulatory region

1995 ◽  
Vol 108 (4) ◽  
pp. 1779-1789 ◽  
Author(s):  
K.C. Chang ◽  
K. Fernandes ◽  
M.J. Dauncey
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Transcriptional Start Site ◽  
Regulatory Region ◽  
Chain Gene ◽  
Specific Expression ◽  
Slow Fibre ◽  
Skeletal Myosin

Members of the myosin heavy chain (MyHC) gene family show developmental stage- and spatial-specificity of expression. We report on the characterization and identification of a porcine skeletal fast MyHC gene, including its corresponding 5′ end cDNA and 5′ regulatory region. This MyHC isoform was found exclusively in skeletal muscles from about the last quarter of gestation through to adulthood. Expression of this isoform was higher postnatally and its spatial distribution resembled a rosette cluster; each with a ring of fast fibres surrounding a central slow fibre. This rosette pattern was absent in the adult diaphragm but about 20% of the fibres continued to express this MyHC isoform. Further in vivo expression studies, in a variety of morphologically and functionally diverse muscles, showed that this particular skeletal MyHC isoform was expressed in fast oxidative-glycolytic fibres, suggesting that it was the equivalent of the fast IIA isoform. Two domains in the upstream regulatory region were found to confer differentiation-specific expression on C2 myotubes (−1007 to -828 and -455 to -101), based on in vitro transient expression assays using the chloramphenicol acetyltransferase (CAT) reporter gene. Interestingly, for high levels of CAT expression to occur, a 3′ region, extending from the transcriptional start site to part. of intron 2, must be present in all the DNA constructs used.

In vivo regulation of the β-myosin heavy chain gene in hypertensive rodent heart

2001 ◽  
Vol 280 (5) ◽  
pp. C1262-C1276 ◽  
Author(s):  
Carola E. Wright ◽  
P. W. Bodell ◽  
F. Haddad ◽  
A. X. Qin ◽  
K. M. Baldwin
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Promoter Activity ◽  
Proximal Promoter ◽  
Future Research ◽  
Chain Gene ◽  
Direct Gene Transfer ◽  
Basal Region ◽  
Mobility Shift

The main goal of this study was to examine the transcriptional activity of different-length β-myosin heavy chain (β-MHC) promoters in the hypertensive rodent heart using the direct gene transfer approach. A hypertensive state was induced by abdominal aortic constriction (AbCon) sufficient to elevate mean arterial pressure by ∼45% relative to control. Results show that β-MHC promoter activity of all tested wild-type constructs, i.e., −3500, −408, −299, −215, −171, and −71 bp, was significantly increased in AbCon hearts. In the normal control hearts, expression of the −71-bp construct was comparable to that of the promoterless vector, but its induction by AbCon was comparable to that of the other constructs. Additional results, based on mutation analysis and DNA gel mobility shift assays targeting βe1, βe2, GATA, and βe3 elements, show that these previously defined cis-elements in the proximal promoter are indeed involved in maintaining basal promoter activity; however, none of these elements, either individually or collectively, appear to be major players in mediating the hypertension response of the β-MHC gene. Collectively, these results indicate that three separate regions on the β-MHC promoter are involved in the induction of the gene in response to hypertension: 1) a distal region between −408 and −3500 bp, 2) a proximal region between −299 and −215 bp, and 3) a basal region within −71 bp of the transcription start site. Future research needs to further characterize these responsive regions to more fully delineate β-MHC transcriptional regulation in response to pressure overload.

IN VIVO GENE REGULATION OF THE ?? MYOSIN HEAVY CHAIN GENE IN RODENT HEART

1998 ◽  
Vol 30 (Supplement) ◽  
pp. 143
Author(s):  
C. E Wright ◽  
F. Haddad ◽  
P. W. Bodell ◽  
K. M. Baldwin
Keyword(s):  
Gene Regulation ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Chain Gene ◽  
Heavy Chain Gene ◽  
Myosin Heavy Chain Gene

Developmental pattern of mouse skeletal myosin heavy chain gene transcripts in vivo and in vitro

Cell ◽  
1987 ◽  
Vol 49 (1) ◽  
pp. 121-129 ◽  
Author(s):  
André Weydert ◽  
Paul Barton ◽  
A.John Harris ◽  
Christian Pinset ◽  
Margaret Buckingham
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Developmental Pattern ◽  
Chain Gene ◽  
Heavy Chain Gene ◽  
Myosin Heavy Chain Gene ◽  
Skeletal Myosin ◽  
Gene Transcripts

In vivo regulation of the β-myosin heavy chain gene in soleus muscle of suspended and weight-bearing rats

2000 ◽  
Vol 278 (6) ◽  
pp. C1153-C1161 ◽  
Author(s):  
Julia M. Giger ◽  
Fadia Haddad ◽  
Anqi X. Qin ◽  
Kenneth M. Baldwin
Keyword(s):  
Myosin Heavy Chain ◽  
Soleus Muscle ◽  
Heavy Chain ◽  
Weight Bearing ◽  
Hindlimb Suspension ◽  
Luciferase Reporter ◽  
Chain Gene ◽  
Direct Gene Transfer ◽  
Luciferase Reporter Gene

In the weight-bearing hindlimb soleus muscle of the rat, ∼90% of muscle fibers express the β-myosin heavy chain (β-MHC) isoform protein. Hindlimb suspension (HS) causes the MHC isoform population to shift from β toward the fast MHC isoforms. Our aim was to establish a model to test the hypothesis that this shift in expression is transcriptionally regulated through specific cis elements of the β-MHC promoter. With the use of a direct gene transfer approach, we determined the activity of different length β-MHC promoter fragments, linked to a firefly luciferase reporter gene, in soleus muscle of control and HS rats. In weight-bearing rats, the relative luciferase activity of the longest β-promoter fragment (−3500 bp) was threefold higher than the shorter promoter constructs, which suggests that an enhancer sequence is present in the upstream promoter region. After 1 wk of HS, the reporter activities of the −3500-, −914-, and −408-bp promoter constructs were significantly reduced (∼40%), compared with the control muscles. However, using the −215-bp construct, no differences in promoter activity were observed between HS and control muscles, which indicates that the response to HS in the rodent appears to be regulated within the −408 and −215 bp of the promoter.

scholarly journals Cardiac myosin heavy chain gene regulation by thyroid hormone involves altered histone modifications

2010 ◽  
Vol 299 (6) ◽  
pp. H1968-H1980 ◽  
Author(s):  
F. Haddad ◽  
W. Jiang ◽  
P. W. Bodell ◽  
A. X. Qin ◽  
K. M. Baldwin
Keyword(s):  
Thyroid Hormone ◽  
Myosin Heavy Chain ◽  
Histone Modifications ◽  
Heavy Chain ◽  
Histone H3 ◽  
Chain Gene ◽  
Thyroid State ◽  
Cis Acting ◽  
Mhc Genes ◽  
Altered Thyroid

The antithetical regulation of cardiac α- and β-myosin heavy chain (MHC) genes by thyroid hormone (T3) is not well understood but appears to involve thyroid hormone interaction with its nuclear receptor and MHC promoters as well as cis-acting noncoding regulatory RNA (ncRNA). Both of these phenomena involve epigenetic regulations. This study investigated the extent that altered thyroid state induces histone modifications in the chromatin associated with the cardiac MHC genes. We hypothesized that specific epigenetic events could be identified and linked to cardiac MHC gene switching in response to a hypothyroid or hyperthyroid state. A hypothyroid state was induced in rats by propylthiouracil treatment (PTU), whereas a hyperthyroid (T3) was induced by T3treatment. The left ventricle was analyzed after 7 days for MHC pre-mRNA expression, and the chromatin was assessed for enrichment in specific histone modifications using chromatin immunoprecipitation quantitative PCR assays. At both the α-MHC promoter and the intergenic region, the enrichment in acetyl histone H3 at K9/14 (H3K9/14ac) and trimethyl histone H3 at K4 (H3K4me3) changed in a similar fashion. They were both decreased with PTU treatment but did not change under T3, except at a location situated 5′ to the antisense intergenic transcription start site. These same marks varied differently on the β-MHC promoter. For example, H3K4me3 enrichment correlated with the β-promoter activity in PTU and T3groups, whereas H3K9/14ac was repressed in the T3group but did not change under PTU. Histone H3K9me was enriched in chromatin of both the intergenic and α-MHC promoters in the PTU group, whereas histone H4K20me1 was enriched in chromatin of β-MHC promoter in the normal control and T3groups. Collectively, these findings provide evidence that specific epigenetic phenomena modulate MHC gene expression in altered thyroid states.

Sign in / Sign up

Export Citation Format

Share Document