scholarly journals alpha-skeletal and alpha-cardiac actin genes are coexpressed in adult human skeletal muscle and heart.

1983 ◽  
Vol 3 (11) ◽  
pp. 1985-1995 ◽  
Author(s):  
P Gunning ◽  
P Ponte ◽  
H Blau ◽  
L Kedes
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Human Skeletal Muscle ◽  
Cdna Clones ◽  
Actin Gene ◽  
Adult Heart ◽  
Adult Human ◽  
Actin Genes ◽  
Cardiac Actin ◽  
Actin Mrna

We determined the actin isotypes encoded by 30 actin cDNA clones previously isolated from an adult human muscle cDNA library. Using 3' untranslated region probes derived from alpha-skeletal, beta- and gamma-actin cDNAs and from an alpha-cardiac actin genomic clone, we showed that 28 of the cDNAs correspond to alpha-skeletal actin transcripts. Unexpectedly, however, the remaining two cDNA clones proved to derive from alpha-cardiac actin mRNA. Sequence analysis confirmed that the two skeletal muscle alpha-cardiac actin cDNAs are derived from transcripts of the cloned alpha-cardiac actin gene. Direct measurements of actin isotype mRNA expression in human skeletal muscle showed that alpha-cardiac actin mRNA is expressed at 5% the level of alpha-skeletal actin. Furthermore, the alpha-cardiac actin gene expressed in skeletal muscle is the same gene which produces alpha-cardiac actin mRNA in the human heart. Of equal surprise, we found that alpha-skeletal actin mRNA accounts for about half of the total actin mRNA in adult heart. Comparison of total actin mRNA levels in adult skeletal muscle and adult heart revealed that the steady-state levels in skeletal muscle are about twofold greater, per microgram of total cellular RNA, than those in heart. Thus, in skeletal muscle and in heart, both of the sarcomeric actin mRNA isotypes are quite abundant transcripts. We conclude that alpha-skeletal and alpha-cardiac actin genes are coexpressed as an actin pair in human adult striated muscles. Since the smooth-muscle actins (aortic and stomach) and the cytoplasmic actins (beta and gamma) are known to be coexpressed in smooth muscle and nonmuscle cells, respectively, we postulate that coexpression of actin pairs may be a common feature of mammalian actin gene expression in all tissues.

alpha-skeletal and alpha-cardiac actin genes are coexpressed in adult human skeletal muscle and heart

1983 ◽  
Vol 3 (11) ◽  
pp. 1985-1995
Author(s):  
P Gunning ◽  
P Ponte ◽  
H Blau ◽  
L Kedes
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Human Skeletal Muscle ◽  
Cdna Clones ◽  
Actin Gene ◽  
Adult Heart ◽  
Adult Human ◽  
Actin Genes ◽  
Cardiac Actin ◽  
Actin Mrna

We determined the actin isotypes encoded by 30 actin cDNA clones previously isolated from an adult human muscle cDNA library. Using 3' untranslated region probes derived from alpha-skeletal, beta- and gamma-actin cDNAs and from an alpha-cardiac actin genomic clone, we showed that 28 of the cDNAs correspond to alpha-skeletal actin transcripts. Unexpectedly, however, the remaining two cDNA clones proved to derive from alpha-cardiac actin mRNA. Sequence analysis confirmed that the two skeletal muscle alpha-cardiac actin cDNAs are derived from transcripts of the cloned alpha-cardiac actin gene. Direct measurements of actin isotype mRNA expression in human skeletal muscle showed that alpha-cardiac actin mRNA is expressed at 5% the level of alpha-skeletal actin. Furthermore, the alpha-cardiac actin gene expressed in skeletal muscle is the same gene which produces alpha-cardiac actin mRNA in the human heart. Of equal surprise, we found that alpha-skeletal actin mRNA accounts for about half of the total actin mRNA in adult heart. Comparison of total actin mRNA levels in adult skeletal muscle and adult heart revealed that the steady-state levels in skeletal muscle are about twofold greater, per microgram of total cellular RNA, than those in heart. Thus, in skeletal muscle and in heart, both of the sarcomeric actin mRNA isotypes are quite abundant transcripts. We conclude that alpha-skeletal and alpha-cardiac actin genes are coexpressed as an actin pair in human adult striated muscles. Since the smooth-muscle actins (aortic and stomach) and the cytoplasmic actins (beta and gamma) are known to be coexpressed in smooth muscle and nonmuscle cells, respectively, we postulate that coexpression of actin pairs may be a common feature of mammalian actin gene expression in all tissues.

Actin genes in Xenopus and their developmental control

Development ◽  
1985 ◽  
Vol 89 (Supplement) ◽  
pp. 125-136
Author(s):  
J. B. Gurdon ◽  
T. J. Mohun ◽  
S. Brennan ◽  
S. Cascio
Keyword(s):  
Skeletal Muscle ◽  
Early Development ◽  
Actin Gene ◽  
Muscle Actin ◽  
Cell Type ◽  
Developmental Control ◽  
Normal Contact ◽  
Actin Genes ◽  
Cardiac Actin ◽  
Cell Type Specific

The results summarized here have established the temporal and regional activation of three kinds of Xenopus actin genes. The cardiac and skeletal muscle actin genes are among the first cell-type-specific genes to be expressed in early development. The first transcripts to be synthesized by these genes appear to be correctly initiated, spliced, and at once translated into proteins. Both cardiac and skeletal actin genes are strongly transcribed in the axial skeletal muscle of embryos. The mechanism by which the cardiac actin gene is first transcribed in only the somite region of an embryo depends, at least in part, on materials already localized in the subequatorial region of a fertilized but uncleaved egg. Cells which acquire this material seem able to activate their cardiac actin genes without requiring normal contact with other cells.

scholarly journals Cardiac actin is the major actin gene product in skeletal muscle cell differentiation in vitro.

1984 ◽  
Vol 4 (8) ◽  
pp. 1449-1453 ◽  
Author(s):  
W Bains ◽  
P Ponte ◽  
H Blau ◽  
L Kedes
Keyword(s):  
Skeletal Muscle ◽  
Muscle Cell ◽  
Skeletal Muscle Cell ◽  
C2c12 Cells ◽  
Adult Skeletal Muscle ◽  
Mature Adult ◽  
Actin Genes ◽  
Cardiac Actin ◽  
Actin Mrna

We examined the expression of alpha-skeletal, alpha-cardiac, and beta- and gamma-cytoskeletal actin genes in a mouse skeletal muscle cell line (C2C12) during differentiation in vitro. Using isotype-specific cDNA probes, we showed that the alpha-skeletal actin mRNA pool reached only 15% of the level reached in adult skeletal muscle and required several days to attain this peak, which was then stably maintained. However, these cells accumulated a pool of alpha-cardiac actin six times higher than the alpha-skeletal actin mRNA peak within 24 h of the initiation of differentiation. After cells had been cultured for an additional 3 days, this pool declined to 10% of its peak level. In contrast, over 95% of the actin mRNA in adult skeletal muscle coded for alpha-actin. This suggests that C2C12 cells express a pattern of sarcomeric actin genes typical of either muscle development or regeneration and distinct from that seen in mature, adult tissue. Concurrently in the course of differentiation the beta- and gamma-cytoskeletal actin mRNA pools decreased to less than 10% of their levels in proliferating cells. The decreases in beta- and gamma-cytoskeletal actin mRNAs are apparently not coordinately regulated.

Cardiac actin is the major actin gene product in skeletal muscle cell differentiation in vitro

1984 ◽  
Vol 4 (8) ◽  
pp. 1449-1453
Author(s):  
W Bains ◽  
P Ponte ◽  
H Blau ◽  
L Kedes
Keyword(s):  
Skeletal Muscle ◽  
Muscle Cell ◽  
Skeletal Muscle Cell ◽  
C2c12 Cells ◽  
Adult Skeletal Muscle ◽  
Mature Adult ◽  
Actin Genes ◽  
Cardiac Actin ◽  
Actin Mrna

We examined the expression of alpha-skeletal, alpha-cardiac, and beta- and gamma-cytoskeletal actin genes in a mouse skeletal muscle cell line (C2C12) during differentiation in vitro. Using isotype-specific cDNA probes, we showed that the alpha-skeletal actin mRNA pool reached only 15% of the level reached in adult skeletal muscle and required several days to attain this peak, which was then stably maintained. However, these cells accumulated a pool of alpha-cardiac actin six times higher than the alpha-skeletal actin mRNA peak within 24 h of the initiation of differentiation. After cells had been cultured for an additional 3 days, this pool declined to 10% of its peak level. In contrast, over 95% of the actin mRNA in adult skeletal muscle coded for alpha-actin. This suggests that C2C12 cells express a pattern of sarcomeric actin genes typical of either muscle development or regeneration and distinct from that seen in mature, adult tissue. Concurrently in the course of differentiation the beta- and gamma-cytoskeletal actin mRNA pools decreased to less than 10% of their levels in proliferating cells. The decreases in beta- and gamma-cytoskeletal actin mRNAs are apparently not coordinately regulated.

Differential patterns of transcript accumulation during human myogenesis

1987 ◽  
Vol 7 (11) ◽  
pp. 4100-4114
Author(s):  
P Gunning ◽  
E Hardeman ◽  
R Wade ◽  
P Ponte ◽  
W Bains ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Carbonic Anhydrase ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Time Course ◽  
Human Skeletal Muscle ◽  
Transcript Accumulation ◽  
Mrna Accumulation ◽  
Adult Human ◽  
Alpha Actin

We evaluated the extent to which muscle-specific genes display identical patterns of mRNA accumulation during human myogenesis. Cloned satellite cells isolated from adult human skeletal muscle were expanded in culture, and RNA was isolated from low- and high-confluence cells and from fusing cultures over a 15-day time course. The accumulation of over 20 different transcripts was compared in these samples with that in fetal and adult human skeletal muscle. The expression of carbonic anhydrase 3, myoglobin, HSP83, and mRNAs encoding eight unknown proteins were examined in human myogenic cultures. In general, the expression of most of the mRNAs was induced after fusion to form myotubes. However, several exceptions, including carbonic anhydrase and myoglobin, showed no detectable expression in early myotubes. Comparison of all transcripts demonstrated little, if any, identity of mRNA accumulation patterns. Similar variability was also seen for mRNAs which were also expressed in nonmuscle cells. Accumulation of mRNAs encoding alpha-skeletal, alpha-cardiac, beta- and gamma-actin, total myosin heavy chain, and alpha- and beta-tubulin also displayed discordant regulation, which has important implications for sarcomere assembly. Cardiac actin was the only muscle-specific transcript that was detected in low-confluency cells and was the major alpha-actin mRNA at all times in fusing cultures. Skeletal actin was transiently induced in fusing cultures and then reduced by an order of magnitude. Total myosin heavy-chain mRNA accumulation lagged behind that of alpha-actin. Whereas beta- and gamma-actin displayed a sharp decrease after initiation of fusion and thereafter did not change, alpha- and beta-tubulin were transiently induced to a high level during the time course in culture. We conclude that each gene may have its own unique determinants of transcript accumulation and that the phenotype of a muscle may not be determined so much by which genes are active or silent but rather by the extent to which their transcript levels are modulated. Finally, we observed that patterns of transcript accumulation established within the myotube cultures were consistent with the hypothesis that myoblasts isolated from adult tissue recapitulate a myogenic developmental program. However, we also detected a transient appearance of adult skeletal muscle-specific transcripts in high-confluence myoblast cultures. This indicates that the initial differentiation of these myoblasts may reflect a more complex process than simple recapitulation of development.

Primary structure of the adult human skeletal muscle voltage-dependent sodium channel

1992 ◽  
Vol 31 (2) ◽  
pp. 131-137 ◽  
Author(s):  
Alfred L. George ◽  
Jeffrey Komisarof ◽  
Roland G. Kallen ◽  
Robert L. Barchi
Keyword(s):  
Skeletal Muscle ◽  
Sodium Channel ◽  
Primary Structure ◽  
Human Skeletal Muscle ◽  
Adult Human ◽  
Voltage Dependent

scholarly journals A three-dimensional culture model of innervated human skeletal muscle enables studies of the adult neuromuscular junction and disease modeling

2018 ◽  
Author(s):  
Mohsen Afshar Bakooshli ◽  
Ethan S Lippmann ◽  
Ben Mulcahy ◽  
Nisha R Iyer ◽  
Christine T Nguyen ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Neuromuscular Junction ◽  
Motor Neuron ◽  
Motor Neurons ◽  
Human Skeletal Muscle ◽  
Disease Modeling ◽  
De Novo ◽  
Muscle Fibers ◽  
Three Dimensional ◽  
Adult Human

SummaryTwo-dimensional (2D) human skeletal muscle fiber cultures are ill equipped to support the contractile properties of maturing muscle fibers. This limits their application to the study of adult human neuromuscular junction (NMJ) development, a process requiring maturation of muscle fibers in the presence of motor neuron endplates. Here we describe a three-dimensional (3D) co-culture method whereby human muscle progenitors mixed with human pluripotent stem cell-derived motor neurons self-organize to form functional NMJ connections within two weeks. Functional connectivity between motor neuron endplates and muscle fibers is confirmed with calcium transient imaging and electrophysiological recordings. Notably, we only observed epsilon acetylcholine receptor subunit protein upregulation and activity in 3D co-culture. This demonstrates that the 3D co-culture system supports a developmental shift from the embryonic to adult form of the receptor that does not occur in 2D co-culture. Further, 3D co-culture treatments with myasthenia gravis patient sera shows the ease of studying human disease with the system. This work delivers a simple, reproducible, and adaptable method to model and evaluate adult human NMJ de novo development and disease in culture.

scholarly journals Sequential activation of alpha-actin genes during avian cardiogenesis: vascular smooth muscle alpha-actin gene transcripts mark the onset of cardiomyocyte differentiation.

1988 ◽  
Vol 107 (6) ◽  
pp. 2575-2586 ◽  
Author(s):  
D L Ruzicka ◽  
R J Schwartz
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Cardiac Cells ◽  
Actin Gene ◽  
Heart Tube ◽  
Specific Expression ◽  
Actin Genes ◽  
Beta Actin ◽  
Smooth Muscle Alpha Actin ◽  
Alpha Actin

The expression of cytoplasmic beta-actin and cardiac, skeletal, and smooth muscle alpha-actins during early avian cardiogenesis was analyzed by in situ hybridization with mRNA-specific single-stranded DNA probes. The cytoplasmic beta-actin gene was ubiquitously expressed in the early chicken embryo. In contrast, the alpha-actin genes were sequentially activated in avian cardiac tissue during the early stages of heart tube formation. The accumulation of large quantities of smooth muscle alpha-actin transcripts in epimyocardial cells preceded the expression of the sarcomeric alpha-actin genes. The accumulation of skeletal alpha-actin mRNAs in the developing heart lagged behind that of cardiac alpha-actin by several embryonic stages. At Hamburger-Hamilton stage 12, the smooth muscle alpha-actin gene was selectively down-regulated in the heart such that only the conus, which subsequently participates in the formation of the vascular trunks, continued to express this gene. This modulation in smooth muscle alpha-actin gene expression correlated with the beginning of coexpression of sarcomeric alpha-actin transcripts in the epimyocardium and the onset of circulation in the embryo. The specific expression of the vascular smooth muscle alpha-actin gene marks the onset of differentiation of cardiac cells and represents the first demonstration of coexpression of both smooth muscle and striated alpha-actin genes within myogenic cells.

Structure and transcription of the actin gene of Trypanosoma brucei

1988 ◽  
Vol 8 (5) ◽  
pp. 2166-2176 ◽  
Author(s):  
M F Ben Amar ◽  
A Pays ◽  
P Tebabi ◽  
B Dero ◽  
T Seebeck ◽  
...  
Keyword(s):  
Trypanosoma Brucei ◽  
Splice Site ◽  
Gene Copy Number ◽  
Gene Copy ◽  
Actin Gene ◽  
S1 Nuclease ◽  
Actin Genes ◽  
Gene Copies ◽  
Actin Mrna

In Trypanosoma brucei, the actin gene is present in a cluster of two, three, or four tandemly linked copies, depending on the strain. Each cluster seems to exist in two allelic versions, as suggested by the polymorphism of both gene number and restriction fragment length in the DNA from cloned trypanosomes. The amplification of the gene copy number probably occurs through unequal sister chromatid exchange. The chromosomes harboring the actin genes belong to the large size class. The coding sequence was 1,128 nucleotides long and showed 60 to 70% homology to other eucaryotic actin genes. Surprisingly, this homology seemed weaker with Trypanosoma congolense, Trypanosoma cruzi, Trypanosoma vivax, Trypanosoma mega, or Leishmania actin-specific sequences. The mRNA was around 1.6 kilobases long and was synthesized at the same level in bloodstream and procyclic forms of the parasite. Large RNA precursors, up to 7.7 kilobases, were found in a pattern identical in strains containing either two or three gene copies. Probing of the flanking regions of the gene with either steady-state or in vitro transcripts, as well as S1 nuclease protection and primer extension experiments, allowed mapping of the 3' splice site of the actin mRNA, 38 nucleotides upstream from the translation initiation codon. A variably sized poly(dT) tract was found about 30 base pairs ahead of the splice site. The largest detected actin mRNA precursor seemed to give rise to at least two additional stable mRNAs. The RNA polymerase transcribing the actin gene exhibited the same sensitivity to inhibition by alpha-amanitin as that transcribing both the spliced leader and the bulk of polyadenylated mRNAs.

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