Chromatin remodelling of the cardiac β-myosin heavy chain gene

To investigate the role of chromatin structure in cardiac gene expression, we used the DNase I and micrococcal nuclease to probe the chromatin structure of the hamster cardiac β-MyHC gene. Two cardiac-specific DNase I hypersensitive sites (DHS) were identified, one of which was mapped to the -2.3 kb (β-2.3 kb) region and the other to the proximal promoter region of the β-MyHC gene. The two sites were readily detectable using nuclei from neonatal hamster heart; however, the proximal promoter site disappeared when adult hamster heart nuclei were used, and the -2.3 kb site decreased in intensity. We were able to demonstrate the gradual disappearance of this proximal promoter DHS by comparing heart nuclei isolated from animals at late-gestation and 1-day-old stages. Furthermore, injecting thyroid hormone caused the disappearance of the proximal promoter DHS in late gestational fetal ventricular nuclei. Digestion of nuclei from various tissues by micrococcal nuclease revealed that the β-MyHC gene proximal promoter exists in an array of three specifically-positioned nucleosomes only in fetal heart chromatin. The β-MyHC gene proximal promoter is DNase I hypersensitive within one of the nucleosomal particles. Our data suggest that chromatin structure may participate actively in cardiac gene expression.

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Chromatin Structure and Cardiac Gene Expression

Journal of Molecular and Cellular Cardiology ◽

10.1006/jmcc.1998.0738 ◽

1998 ◽

Vol 30 (9) ◽

pp. 1673-1681 ◽

Cited By ~ 6

Author(s):

Weei-Yuarn Huang ◽

Choong-Chin Liew

Keyword(s):

Gene Expression ◽

Chromatin Structure ◽

Cardiac Gene Expression ◽

Cardiac Gene

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Changes in chromatin structure at the replication fork. DNase I and trypsin-micrococcal nuclease effects on approximately 300- and 150-base pair nascent DNAs.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(17)44414-0 ◽

1983 ◽

Vol 258 (18) ◽

pp. 11274-11279

Author(s):

G Galili ◽

A Levy ◽

K M Jakob

Keyword(s):

Chromatin Structure ◽

Base Pair ◽

Replication Fork ◽

Dnase I ◽

Micrococcal Nuclease

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Doppler Echocardiographic Assessment and Cardiac Gene Expression Analysis of the Left Ventricle in Myocardial lnfarcted Rats

Japanese Circulation Journal ◽

10.1253/jcj.62.436 ◽

1998 ◽

Vol 62 (6) ◽

pp. 436-442 ◽

Cited By ~ 14

Author(s):

Naruhito Shimizu ◽

Minoru Yoshiyama ◽

Kazuhide Takeuchi ◽

Akihisa Hanatani ◽

Shokei Kim ◽

...

Keyword(s):

Gene Expression ◽

Left Ventricle ◽

Expression Analysis ◽

Gene Expression Analysis ◽

Cardiac Gene Expression ◽

Cardiac Gene ◽

Echocardiographic Assessment

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Myocardin Marks the Earliest Cardiac Gene Expression and Plays an Important Role in Heart Development

The Anatomical Record ◽

10.1002/ar.20756 ◽

2008 ◽

Vol 291 (10) ◽

pp. 1200-1211 ◽

Cited By ~ 8

Author(s):

Jian-Fu Chen ◽

Shusheng Wang ◽

Qiulian Wu ◽

Dongsun Cao ◽

Thiha Nguyen ◽

...

Keyword(s):

Gene Expression ◽

Heart Development ◽

Cardiac Gene Expression ◽

Cardiac Gene

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Major histocompatibility complex class I genes in murine fibrosarcoma IC9 are down regulated at the level of the chromatin structure

Molecular and Cellular Biology ◽

10.1128/mcb.9.7.3136-3142.1989 ◽

1989 ◽

Vol 9 (7) ◽

pp. 3136-3142

Author(s):

U Maschek ◽

W Pülm ◽

S Segal ◽

G J Hämmerling

Keyword(s):

Major Histocompatibility Complex ◽

Major Histocompatibility Complex Class ◽

Chromatin Structure ◽

Dnase I ◽

Class I ◽

Micrococcal Nuclease ◽

Complex Class ◽

Major Histocompatibility ◽

Histocompatibility Complex ◽

Nuclear Extracts

The fibrosarcoma IC9 is deficient in the expression of the major histocompatibility complex class I genes Kb, Kk, and Dk and expresses only the Db molecule. Because class I deficiency may enable tumor cells to escape the immune response by cytotoxic T lymphocytes, we investigated why the class I genes are not expressed. Expression of the silent class I genes could not be induced, but all known DNA-binding factors specific for class I genes could be detected in nuclear extracts of IC9 cells. After cloning of the silent Kb gene from the IC9 cells and subsequent transfection of this cloned Kb gene into LTK- and IC9 cells, normal Kb antigens were expressed on the cell surface of both cell lines. Digestion of the chromatin of IC9 cells with micrococcal nuclease and DNase I showed a decreased nuclease sensitivity of the silent class I genes in comparison with active genes and the absence of DNase I hypersensitive sites in the promoter region of the silent Dk gene. These findings demonstrate that class I expression is turned off by a cis-acting regulatory mechanism at the level of the chromatin structure.

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Abstract 247: Scaffold-stiffness Dependent Notch1 Activation Regulates Cardiogenic Gene Expression In Cardiac Progenitor Cells

Circulation Research ◽

10.1161/res.113.suppl_1.a247 ◽

2013 ◽

Vol 113 (suppl_1) ◽

Author(s):

Archana V Boopathy ◽

Pao L Che ◽

Yoshie Narui ◽

Khalid Salaita ◽

Michael E Davis

Keyword(s):

Gene Expression ◽

Smooth Muscle ◽

Cardiac Function ◽

Progenitor Cells ◽

Adult Stem Cells ◽

Cardiac Progenitor Cells ◽

Critical Pathway ◽

Cardiac Gene Expression ◽

Self Assembling ◽

Cardiac Gene

Rationale: Cardiac progenitor cells (CPCs) are multipotent, self-renewing cells that can regenerate the myocardium and improve cardiac function in animal models of myocardial infarction (MI). However, limited survival of stem/progenitor cells inhibits cardiac regeneration. Force dependent Notch activation promotes cardiac development and cardiac gene expression in many adult stem cells. As dysregulation of Notch signaling leads to embryonic lethal cardiovascular defects, activating this critical pathway during cell transplantation could improve efficacy of stem cell therapy. Objective: Investigate i) whether self-assembling peptide scaffolds can be used to activate Notch1 signaling in CPCs to promote cardiogenic differentiation and ii) the effect of scaffold stiffness on Notch1 activation and differentiation. Methods: Rat CPCs (c-kit + ) were cultured for 48h in 3D self-assembling scaffolds of varying stiffness (1% low, 2% high): empty scaffolds (RADA), scaffolds modified with peptide mimicking Notch1 ligand, Jagged1 (RJAG), or scaffolds modified with a scrambled peptide (RSCR) and cardiogenic gene expression measured by qRT-PCR. CHO cells expressing Notch1 responsive YFP were also cultured in the above scaffolds for 48h and YFP expression was determined. Results are mean ± SEM with p<0.05 considered significant by one or two-way ANOVA with appropriate post test. Results: In the Notch1 reporter cells, Notch1 activation increased significantly in presence of RJAG (p<0.01) and on increasing scaffold stiffness (p<0.01,n=6) indicating scaffold stiffness-dependent Notch1 activation. Culture of CPCs in RJAG containing 1% scaffolds (low stiffness) significantly increased early endothelial and smooth muscle but not cardiac gene expression while in 2% scaffolds (high stiffness) significantly increased only cardiac and not endothelial or smooth muscle gene expression (p<0.05, n≥4). Conclusions: Taken together, these data show that i) Notch1 activation in 3D is dependent on ligand density and scaffold stiffness and ii) stiffness dependent Notch1 activation differentially regulates cardiogenic gene expression in CPCs. Therefore, delivery of CPCs in JAG containing scaffolds could be used to improve cardiac function following MI.

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