Molecular Mechanisms of Myofibril Assembly in Heart.

Auerbach, Daniel; RothenRuthishauser, Barbara; Bantle, Stefan; Leu, Martin; Ehler, Elisabeth; Helfman, David M.; Perriard, Jean‐Claude

doi:10.1247/csf.22.139

Cited by 36 publications

(26 citation statements)

References 27 publications

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“…A cross-reacting antibody would also explain the detection of skelemin in smooth muscle (17). Previous investigations on myomesin expression by several laboratories have characterized myomesin as a sarcomeric protein and also reported its expression exclusively in striated muscle (8,12,15,27,31,34,35). In the present study we confirm by the means of RT-PCR and immunodetection that the expression of all myomesin isoforms is restricted to heart and skeletal muscle.…”

Section: Fig 10supporting

confidence: 85%

A Novel Marker for Vertebrate Embryonic Heart, the EH-myomesin Isoform

Agarkova

Auerbach

Ehler

et al. 2000

Journal of Biological Chemistry

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Myomesin is a structural component of the M-band that is expressed in all types of striated muscle. Its primary function may be the maintenance of the thick filament lattice and its anchoring to the elastic filament system composed of titin. Different myomesin isoforms have been described in chicken and mice, but no particular function has been assigned to them. Here we investigate the spatio-temporal expression pattern of myomesin isoforms by means of reverse transcriptasepolymerase chain reaction and isoform-specific antibodies. We find that two alternative splicing events give rise to four myomesin isoforms in chicken contrary to only one splicing event with two possible isoforms in mice. A splicing event at the C terminus results in two splice variants termed H-myomesin and S-myomesin, which represent the major myomesin species in heart and skeletal muscle of avian species, respectively. In contrast, in mammalian heart and skeletal muscle only S-myomesin is expressed. In embryonic heart of birds and mammals, alternative splicing in the central part of the molecule gives rise to the isoform that we termed EH-myomesin. It represents the major myomesin isoform at early embryonic stages of heart but is rapidly down-regulated around birth. Thus, the strict developmental regulation of the EH-myomesin makes it an ideally suited marker for embryonic heart.

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Section: Fig 10supporting

confidence: 85%

A Novel Marker for Vertebrate Embryonic Heart, the EH-myomesin Isoform

Agarkova

Auerbach

Ehler

et al. 2000

Journal of Biological Chemistry

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“…Isolation and culture of embryonic rat cardiomyocytes (ERC) Embryonic (day 14) rat hearts were dissected, digested with collagenase (Worthington Biochemical Corp., Freehold, NJ) and pancreatin (Gibco Laboratories, Grand Island, NY) and cultured in maintenance medium (20% medium M199, 75% DBSS-K, 4% horse serum, 4 mM glutamine, 1% penicillin/streptomycin, 0.1 mM phenylephrine; DBSS-K: 6.8 g/l NaCl, 0.14 mM NaH2PO4, 0.2 mM CaCl2, 0.2 mM MgSO4, 1 mM dextrose, 2.7 mM NaHCO3) in fibronectin-coated (10 µg/ml; Sigma) plastic dishes (Nunc) (Auerbach et al, 1997).…”

Section: Methodsmentioning

confidence: 99%

Sequential myofibrillar breakdown accompanies mitotic division of mammalian cardiomyocytes

Ahuja¹,

Perriard²,

Perriard³

et al. 2004

Journal of Cell Science

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The contractile tissue of the heart is composed of individual cardiomyocytes. During mammalian embryonic development, heart growth is achieved by cell division while at the same time the heart is already exerting its essential pumping activity. There is still some debate whether the proliferative activity is carried out by a less differentiated, stem cell-like type of cardiomyocytes or whether embryonic cardiomyocytes are able to perform both of these completely different dynamic tasks, contraction and cell division. Our analysis of triple-stained specimen of cultured embryonic cardiomyocytes and of whole mount preparations of embryonic mouse hearts by confocal microscopy revealed that differentiated cardiomyocytes are indeed able to proliferate. However, to go through cell division, a disassembly of the contractile elements, the myofibrils, has to take place. This disassembly occurs in two steps with Z-disk and thin (actin)-filament-associated proteins getting disassembled before disassembly of the M-bands and the thick (myosin) filaments happens. After cytokinesis reassembly of the myofibrillar proteins to their mature cross-striated pattern can be seen. Another interesting observation was that the cell-cell contacts remain seemingly intact during division, probably reflecting the requirement of intact integration sites of the individual cells in the contractile tissue. Our results suggest that embryonic cardiomyocytes have developed an interesting strategy to deal with their major cytoskeletal elements, the myofibrils, during mitosis. The complex disassembly-reassembly process might also provide a mechanistic explanation, why cardiomyocytes cede to divide postnatally.

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“…Neonatal rat hearts were dissected, digested with collagenase (Worthington Biochemical) as well as pancreatin (GIBCO Laboratories), and plated as previously described (Auerbach et al 1997). Two hours prior to transfection, plating medium was exchanged to transfection medium (20% M199, 73% DBSS-K [6.8 g/L NaCl, 0.14 mM NaH 2 PO 4 , 0.2 mM CaCl 2 , 0.2 mM MgSO 4 , 1 mM dextrose, 2.7 mM NaHCO 3 ], 4% horse serum, and 2% glutamine 200 mM).…”

Section: Transfection Experimentsmentioning

confidence: 99%

“…Cells have been transfected with a plasmid containing Flag-tagged junD cDNA (generous gift from Dr. Latifa Bakiri) under the control of the cytomegalovirus promoter using Escort III (Sigma) according to the manufacturer's protocol. After 4 h, medium has been replaced by maintenance medium (Auerbach et al 1997). After 72 h, cells have been fixed, costained with a mouse monoclonal anti-Flag antibody (Chemicon) and phalloidin (Molecular Probes), mounted, and analyzed by fluorescence microscopy as previously described.…”

Section: Transfection Experimentsmentioning

confidence: 99%

Distinct functions of junD in cardiac hypertrophy and heart failure

Ricci¹,

Eriksson²,

Oudit³

et al. 2005

Genes Dev.

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Cardiac hypertrophic stimuli induce both adaptive and maladaptive growth response pathways in heart. Here we show that mice lacking junD develop less adaptive hypertrophy in heart after mechanical pressure overload, while cardiomyocyte-specific expression of junD in mice results in spontaneous ventricular dilation and decreased contractility. In contrast, fra-1 conditional knock-out mice have a normal hypertrophic response, whereas hearts from fra-1 transgenic mice decompensate prematurely. Moreover, fra-1 transgenic mice simultaneously lacking junD reveal a spontaneous dilated cardiomyopathy associated with increased cardiomyocyte apoptosis and a primary mitochondrial defect. These data suggest that junD promotes both adaptive-protective and maladaptive hypertrophy in heart, depending on its expression levels.Supplemental material is available at http://www.genesdev.org.

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Molecular Mechanisms of Myofibril Assembly in Heart.

Cited by 36 publications

References 27 publications

A Novel Marker for Vertebrate Embryonic Heart, the EH-myomesin Isoform

A Novel Marker for Vertebrate Embryonic Heart, the EH-myomesin Isoform

Sequential myofibrillar breakdown accompanies mitotic division of mammalian cardiomyocytes

Distinct functions of junD in cardiac hypertrophy and heart failure

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