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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1993-12-16
pubmed:abstractText
The Crooked Neck Dwarf (cn) mutation in chickens causes marked changes in intact embryonic skeletal muscle. We have investigated whether the cn/cn phenotype develops in vitro, and if cultured muscle cells are suitable for studies of this mutation. The properties of cn/cn muscle cells maintained in low density primary cultures (6.25 x 10(3) cells/cm2) are described in this report. In normal muscle cells, the alpha ryanodine receptor (RyR) isoform appears prior to, and at greater levels than, the beta RyR, and is detected in mononucleated myocytes. The beta RyR isoform appears within 24 hr after the initiation of myotube formation, which is earlier than anticipated from studies with intact embryonic muscle. Normal alpha RyR protein is not detected in cultured cn/cn muscle cells, whereas the beta RyR, the alpha 1-subunit of the dihydropyridine receptor, the sarcoplasmic reticulum Ca(2+)-ATPase, and calsequestrin are expressed at comparable levels in normal and mutant muscle cells. Calcium transients elicited by electrical stimulation, acetylcholine, and caffeine are similar in normal and cn/cn cultured myotubes and are blocked by ryanodine in both cell types. In addition, comparable L- and T-type calcium currents are observed in normal and mutant muscle cells, suggesting that both the alpha 1-subunit of the dihydropyridine receptor and the beta RyR in mutant muscle cells are functional. Normal and cn/cn muscle cells proliferate and form myotubes in a similar manner. These latter events do not appear to depend on sarcoplasmic reticulum calcium release, as they also occur in normal muscle cells in which calcium release is prevented by chronic treatment with 100 microM ryanodine. Both cn/cn and ryanodine-treated normal muscle cells exhibit morphological changes similar to those observed in intact cn/cn skeletal muscle. Thus, the mutant phenotype observed in ovo is partially expressed under low density culture conditions, and neither beta RyR protein nor its function appear to be capable of preventing the associated changes.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
1058-8388
pubmed:author
pubmed:issnType
Print
pubmed:volume
197
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
189-202
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1993
pubmed:articleTitle
Crooked neck dwarf (cn) mutant chicken skeletal muscle cells in low density primary cultures fail to express normal alpha ryanodine receptor and exhibit a partial mutant phenotype.
pubmed:affiliation
Department of Pharmacology, University of Nevada School of Medicine, Reno 89557.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't