Ectopic expression and dynamics of TPM1α and TPM1κ in myofibrils of avian myotubes

Wang, Jushuo; Sanger, Jean M.; Kang, Songman; Thurston, Harold; Abbott, Lynn; Dube, Dipak K.; Sanger, Joseph W.

doi:10.1002/cm.20221

Cited by 38 publications

(67 citation statements)

References 40 publications

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“…There was no change in the dynamics of these two TM isoforms during cardiac myofibrillogenesis in contrast to the case in skeletal muscle cells [Wang et al, 2007]. These results are discussed in terms of thin filament assembly as premyofibrils transform into mature myofibrils in both cardiac and skeletal muscle cells [Wang et al, 2007].…”

Section: Introductioncontrasting

confidence: 56%

Tropomyosin expression and dynamics in developing avian embryonic muscles

Wang

Thurston

Essandoh

et al. 2008

Cell Motil. Cytoskeleton

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The expression of striated muscle proteins occurs early in the developing embryo in the somites and forming heart. A major component of the assembling myofibrils is the actin-binding protein tropomyosin. In vertebrates, there are four genes for tropomyosin (TM), each of which can be alternatively spliced. TPM1 can generate at least 10 different isoforms including the striated muscle-specific TPM1alpha and TPM1kappa. We have undertaken a detailed study of the expression of various TM isoforms in 2-day-old (stage HH 10-12; 33 h) heart and somites, the progenitor of future skeletal muscles. Both TPM1alpha and TPM1kappa are expressed transiently in embryonic heart while TPM1alpha is expressed in somites. Both RT-PCR and in situ hybridization data suggest that TPM1kappa is expressed in embryonic heart whereas TPM1alpha is expressed in embryonic heart, and also in the branchial arch region of somites, and in the somites. Photobleaching studies of Yellow Fluorescent Protein-TPM1alpha and -TPM1kappa expressed in cultured avian cardiomyocytes revealed that the dynamics of the two probes was the same in both premyofibrils and in mature myofibrils. This was in sharp contrast to skeletal muscle cells in which the fluorescent proteins were more dynamic in premyofibrils. We speculate that the differences in the two muscles is due to the appearance of nebulin in the skeletal myocytes premyofibrils transform into mature myofibrils.

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Section: Introductioncontrasting

confidence: 56%

Tropomyosin expression and dynamics in developing avian embryonic muscles

Wang

Thurston

Essandoh

et al. 2008

Cell Motil. Cytoskeleton

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“…Because of the large number of protein pairs possible in a complicated network such as the Z-band, an approach like this requires a large number of experiments: if one varies both acceptor and donor locations, each pair represents up to four FRET experiments that must be done. Experiments aimed at discovering stepwise changes associated with myofibril development add yet another layer of complexity to an already large data array [Rhee et al, 1997;Sanger et al, 2004Sanger et al, , 2005Golson et al, 2004;Wang et al 2005a,b;Wang et al, 2007]. We have shown that careful statistical analysis, in our case, multiple linear regression, can be used to extract meaningful information from multifaceted data sets.…”

Section: Discussionmentioning

confidence: 84%

“…The z-bodies of premyofibrils are located at the leading edges of the myotubes whereas the Z-bands of the mature myofibrils are best studied in the central shafts of the same myotubes ( Fig. 1) [Wang et al 2005a[Wang et al , 2007[Wang et al , 2008. To look for changes in molecular organization associated with Zband maturation, mYFP-alpha-actinin was co-expressed with mCFP-alpha-actinin in cultured quail skeletal myotubes.…”

Section: Alpha-actinin and Alpha-actininmentioning

confidence: 99%

“…Behind this lies a remarkable degree of organization that arises during development of the embryo and that is maintained through an organism's lifetime by the orderly exchange of bound sarcomeric proteins with those in the cytoplasmic pool [Wang et al, 2005a[Wang et al, , 2007[Wang et al, , 2008. Inside a muscle fiber, the myofibril is the basic structural unit comprising the force generation machinery [Clark et al, 2002].…”

Section: Introductionmentioning

confidence: 98%

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Tracking changes in Z‐band organization during myofibrillogenesis with FRET imaging

Stout

Wang

Sanger

et al. 2008

Cell Motil. Cytoskeleton

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There are a large number of proteins associated with Z-bands in myofibrils, but the precise arrangements of most of these proteins in Z-bands are largely unknown. Even less is known about how these arrangements change during myofibrillogenesis. We have begun to address this issue using Sensitized Emission Fluorescence Resonance Energy Transfer (SE-FRET) microscopy. Cultured skeletal muscle cells from quail embryos were transfected to express fusions of alpha-actinin, FATZ, myotilin, or telethonin with cyan and yellow fluorescent proteins in various pair wise combinations. FATZ and myotilin were selected because previous biochemical studies have suggested that they bind to alpha-actinin, the major protein of the Z-band. Telethonin was selected for its reported ability to bind FATZ. Statistical analysis of data from FRET imaging studies yield results that are in agreement with published biochemical data suggesting that FATZ and myotilin bind to alpha-actinin near its C-terminus as well as to each other and that a region near the amino-terminus of FATZ is responsible for its interaction with telethonin. In addition, our analysis has revealed changes in the arrangement of alpha-actinin and FATZ that take place during the transition as the z-bodies of premyofibrils fuse to form the Z-bands of mature myofibrils. There was no evidence for a change in the arrangement of myotilin as z-bodies transformed into Z-bands. Myotilin is one Z-band protein that does not exhibit decreased dynamics as z-bodies fuse to form Z-bands. These FRET results from living cells support a stepwise model for the assembly of myofibrils.

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“…On the other hand, tropomyosins fused to non-coiled-coil fluorescent proteins can incorporate into sarcomeres suggesting that the mutant tropomyosin in these families might not be completely non-functional. 34 If, however, the extended mutant a-tropomyosin in the present patients is nonfunctional, it would make these patients comparable to the NM patient homozygous for an early nonsense mutation in the TPM3 gene described by Tan et al 17 The present patients would then have no functional slow a-tropomyosin in their slow, type 1, muscle fibres, explaining why the type 1 muscle fibres are severely hypotrophic. The only functional tropomyosin in the patients' type 1 fibres would be whatever b-tropomyosin is present.…”

Section: Discussionmentioning

confidence: 66%

Identification of a founder mutation in TPM3 in nemaline myopathy patients of Turkish origin

et al. 2008

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To date, six genes are known to cause nemaline (rod) myopathy (NM), a rare congenital neuromuscular disorder. In an attempt to find a seventh gene, we performed linkage and subsequent sequence analyses in 12 Turkish families with recessive NM. We found homozygosity in two of the families at 1q12-21.2, a region encompassing the c-tropomyosin gene (TPM3) encoding slow skeletal muscle a-tropomyosin, a known NM gene. Sequencing revealed homozygous deletion of the first nucleotide of the last exon, c.913delA of TPM3 in both families. The mutation removes the last nucleotide before the stop codon, causing a frameshift and readthrough across the termination signal. The encoded aTm slow protein is predicted to be 73 amino acids longer than normal, and the extension to the protein is hypothesised to be unable to form a coiled coil. The resulting tropomyosin protein may therefore be non-functional. The affected children in both families were homozygous for the mutation, while the healthy parents were mutation carriers. Both of the patients in Family 1 had the severe form of NM, and also an unusual chest deformity. The affected children in Family 2 had the intermediate form of NM. Muscle biopsies showed type 1 (slow) fibres to be markedly smaller than type 2 (fast) fibres. Previously, there had been five reports, only, of NM caused by mutations in TPM3. The mutation reported here is the first deletion to be identified in TPM3, and it is likely to be a founder mutation in the Turkish population.

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Ectopic expression and dynamics of TPM1α and TPM1κ in myofibrils of avian myotubes

Cited by 38 publications

References 40 publications

Tropomyosin expression and dynamics in developing avian embryonic muscles

Tropomyosin expression and dynamics in developing avian embryonic muscles

Tracking changes in Z‐band organization during myofibrillogenesis with FRET imaging

Identification of a founder mutation in TPM3 in nemaline myopathy patients of Turkish origin

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