Molecular cloning and sequence of Sparus aurata skeletal myosin light chains expressed in white muscle: developmental expression and thyroid regulation

SUMMARY Two full-length cDNA clones encoding the skeletal myosin light chain 2 (MLC2; 1452bp) and myosin light chain 3 (MLC3; 972bp) were isolated from a cDNA library prepared from gilthead sea bream Sparus aurata larvae. The MLC2 cDNA encoded a predicted protein of 170 residues that was 79% identical to rabbit MLC2 over the entire length and 87% identical within the Ca2+-binding region. The deduced amino acid sequence of MLC3 was 153 residues in length and was 91% and 69% identical to the zebrafish and rabbit MLC3, respectively. Northern blot analysis revealed that in adults both transcripts were expressed in fast white muscle only. MLC2 appeared earlier in development: MLC2 transcripts were detectable from the beginning of segmentation, whereas MLC3 transcripts did not appear until 27h post-fertilisation. At this developmental stage, a second MLC2 transcript of 0.89 kilobase-pairs was present. MLCs exhibited a different age-related pattern of response to varied thyroidal states, which were experimentally induced by the administration of 1μgg−1bodymass of thyroxine (T4) or triiodothyronine (T3), or 5ngg−1bodymass of the hypothyroidal compound thiourea; MLC3 expression was not significantly affected, whereas levels of MLC2 transcripts were significantly elevated in the white muscle only of juvenile sea bream after administration of T4. Although the mechanism of thyroidal regulation of MLC expression remains unknown, the present results suggest that different regulatory mechanisms exist for different MLCs.

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Characterization and ontogenetic expression analysis of the myosin light chains from the fast white muscle of mandarin fish Siniperca chuatsi

Journal of Fish Biology ◽

10.1111/j.1095-8649.2011.02929.x ◽

2011 ◽

Vol 78 (4) ◽

pp. 1225-1238 ◽

Cited By ~ 9

Author(s):

W. Y. Chu ◽

J. Chen ◽

R. X. Zhou ◽

F. L. Zhao ◽

T. Meng ◽

...

Keyword(s):

Expression Analysis ◽

White Muscle ◽

Light Chains ◽

Myosin Light Chains ◽

Mandarin Fish ◽

Siniperca Chuatsi

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Molecular Cloning and Sequencing of Myosin Light Chains in Human Megakaryoblastic Leukemia Cells.

Journal of Smooth Muscle Research ◽

10.1540/jsmr.37.25 ◽

2001 ◽

Vol 37 (1) ◽

pp. 25-38 ◽

Cited By ~ 4

Author(s):

Mariko WATANABE ◽

Mika KOHRI ◽

Masaaki TAKAISHI ◽

Ryouich HORIE ◽

Masaaki HIGASHIHARA

Keyword(s):

Molecular Cloning ◽

Leukemia Cells ◽

Light Chains ◽

Myosin Light Chains ◽

Cloning And Sequencing ◽

Megakaryoblastic Leukemia

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Synthesis of rat myosin light chains in heterokaryons formed between undifferentiated rat myoblasts and chick skeletal myocytes.

The Journal of Cell Biology ◽

10.1083/jcb.91.1.11 ◽

1981 ◽

Vol 91 (1) ◽

pp. 11-16 ◽

Cited By ~ 20

Author(s):

W E Wright

Keyword(s):

Primary Cultures ◽

Muscle Cells ◽

Thigh Muscle ◽

Light Chains ◽

Myosin Light Chains ◽

Control Of Gene Expression ◽

Cell Functions ◽

Cell Extracts ◽

Skeletal Myosin ◽

Species Specific

The control of gene expression during terminal myogenesis was explored in heterokaryons between differentiated and undifferentiated myogenic cells by analyzing the formation of species specific myosin light chains of chick and rat skeletal muscle. Dividing L6 rat myoblasts served as the biochemically undifferentiated parent. The differentiated parental cells were mononucleated muscle cells (myocytes) that were obtained from primary cultures of embryonic chick thigh muscle by blocking myotube formation with EGTA and later incubating the postimitotic cells in cytochalasin B. Heterokaryons were isolated by the selective rescue of fusion products between cells previously treated with lethal doses of different cell poisons. 95-99% pure populations of heterokaryons formed between undifferentiated rat myoblasts and differentiated chick myocytes were obtained. The cells were labeled with [35S]methionine, and whole cell extracts were analyzed on two-dimensional polyacrylamide gels. These heterokaryons synthesize the light chain of chick myosin and both embryonic and adult light chains of rat skeletal myosin. Control homokaryons formed by fusing undifferentiated cells to themselves did not synthesize skeletal myosin light chains. Control heterokaryons formed between undifferentiated rat myoblasts and chick fibroblasts also failed to synthesize myosin light chains. These results indicate that differentiated chick muscle cells provide some factor that induces L6 myoblasts to synthesize rat myosin light chains. This system provides a model for investigating the processes by which differentiated cell functions are induced.

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Cleavage points of rabbit skeletal myosin light chains selectively modified in situ by limited proteolysis: structural characteristics of the neoformed isozymes

FEBS Letters ◽

10.1016/0014-5793(95)00743-s ◽

1995 ◽

Vol 369 (2-3) ◽

pp. 255-259 ◽

Cited By ~ 5

Author(s):

Jean-Marc Burgat ◽

Charis Ghelis ◽

Robert Cardinaud

Keyword(s):

Structural Characteristics ◽

Limited Proteolysis ◽

Light Chains ◽

Myosin Light Chains ◽

Skeletal Myosin

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Molecular cloning and sequence of gilthead sea bream (Sparus aurata) α-skeletal actin: tissue and developmental expression

Comparative Biochemistry and Physiology Part B Biochemistry and Molecular Biology ◽

10.1016/s1096-4959(01)00381-5 ◽

2001 ◽

Vol 130 (1) ◽

pp. 13-21 ◽

Cited By ~ 5

Author(s):

Katerina A. Moutou ◽

Silvia Socorro ◽

Deborah M. Power ◽

Zissis Mamuris ◽

Adelino V.M. Canario

Keyword(s):

Molecular Cloning ◽

Sparus Aurata ◽

Developmental Expression ◽

Gilthead Sea Bream ◽

Sea Bream

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Induction of muscle genes in neural cells.

The Journal of Cell Biology ◽

10.1083/jcb.98.2.427 ◽

1984 ◽

Vol 98 (2) ◽

pp. 427-435 ◽

Cited By ~ 37

Author(s):

W E Wright

Keyword(s):

Cell Lines ◽

Neural Cell ◽

Light Chains ◽

Myosin Light Chains ◽

Neural Cells ◽

Cell Hybrids ◽

Skeletal Myosin ◽

Muscle Genes ◽

Inducing Factors ◽

Neural Cell Lines

The regulation of skeletal muscle genes was examined in heterokaryons formed by fusing differentiated chick skeletal myocytes to four different rat neural cell lines. Highly enriched populations of heterokaryons isolated using irreversible biochemical inhibitors were labeled with [35S]methionine and analyzed on two-dimensional gels. Rat skeletal myosin light chains were induced in three of the four cell combinations. The one exception, the S-20 cholinergic cell line, not only failed to synthesize rat muscle proteins but also suppressed chick myogenic functions. Experiments with heterokaryons between chick myocytes and cells from whole embryonic rat brain cultures demonstrated that rat skeletal myosin light chains are inducible in normal diploid neural cells as well as in established neural cell lines. In contrast, dividing cell hybrids between rat myoblasts and rat glial cells were nonmyogenic. These results demonstrate that although neural cells may contain factors that prevent the decision to differentiate along myogenic lines in cell hybrids, most neural cell lines do not dominantly suppress the expression of muscle structural genes in heterokaryons. Furthermore, the skeletal myosin light chain genes in most neural cell lines are regulated by a mechanism that permits them to respond to putative chick skeletal myocyte-inducing factors. The "open" state of these myogenic genes may explain many of the reports of apparent "transdifferentiation" to muscle in neural cultures and neural tumors.

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Dictyostelium discoideum myosin: isolation and characterization of cDNAs encoding the regulatory light chain

Molecular and Cellular Biology ◽

10.1128/mcb.9.7.3073-3080.1989 ◽

1989 ◽

Vol 9 (7) ◽

pp. 3073-3080

Author(s):

S R Tafuri ◽

A M Rushforth ◽

E R Kuczmarski ◽

R L Chisholm

Keyword(s):

Amino Acid ◽

Light Chain ◽

Base Pair ◽

Calcium Binding ◽

Expression Patterns ◽

Light Chains ◽

Myosin Light Chains ◽

Base Pairs ◽

Isolation And Characterization ◽

Skeletal Myosin

Phosphorylation of the regulatory light chains (RMLC) of nonmuscle myosin can increase the actin-activated ATPase activity and filament formation. Little is known about these regulatory mechanisms and how the RMLC are involved in ATP hydrolysis. To better characterize the nonmuscle RMLC, we isolated cDNAs encoding the Dictyostelium RMLC. Using an antibody specific for the RMLC, we screened a lambda gt11 expression library and obtained a 200-base-pair clone that encoded a portion of the RMLC. The remainder of the sequence was obtained from two clones identified by DNA hybridization, using the 200-base-pair cDNA. The composite RMLC cDNA was 645 nucleotides long. It contained 60 base pairs of 5' untranslated, 483 bases of coding, and 102 base pairs of 3' untranslated sequence. The amino acid sequence predicted an 18,300-dalton protein that shares 42% amino acid identity with Dictyostelium calmodulin and 30% identity with the chicken skeletal myosin RMLC. This sequence contained three regions that were similar to the E-F hand calcium-binding domains found in calmodulin, troponin C, and other myosin light chains. A sequence similar to the phosphorylation sequence found in chicken gizzard and skeletal myosin light chains was found at the amino terminus. Genomic Southern blot analysis suggested that the Dictyostelium genome contains a single gene encoding the RMLC. Analysis of RMLC expression patterns during Dictyostelium development indicated that accumulation of this mRNA increases just before aggregation and again during culmination. This pattern is similar to that obtained for the Dictyostelium essential myosin light chain and suggests that expression of the two light chains is coordinated during development.

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