Divergent mechanisms in generating molecular variations of αRYR and βRYR in turkey skeletal muscle
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(1) Molecular variations in two turkey skeletal muscle ryanodine receptor gene isoforms, αRYR and βRYR, were analyzed by cloning and sequencing the entire cDNAs of the two isoforms. (2) Ten alternative splicing transcript variants (ASTVs) in the αRYR isoform were identified. These variants were clustered in three alternative splicing regions (ASRs). Two ASRs overlap with the divergent regions (DRs) of the two isoforms. Only four ASTVs did not contain a frame shift and potentially can be translated into αRYR channel proteins. The expression of these three ASTVs was developmentally or environmentally regulated. (3) Ten SNPs and eight haplotypes, divergent in the ten SNP positions, were identified in βRYR. Although the ten SNPs were synonymous, different mRNA secondary structures of βRYR and different stability of the structures were predicted for several SNPs. (4) The intriguing finding of this study is that αRYR and βRYR use completely divergent mechanisms to generate molecular variations. Alternative splicing generates ASTVs of αRYR, whereas the presence of SNPs may change the secondary mRNA structure of βRYR. These divergent mechanisms could affect calcium channel activity of either or both RYR isoforms.
KeywordsRyanodine receptor Alternative splicing SNP Turkey
This research was supported by USDA-National Research Initiative Grant 2001-01581, by the Michigan State University Animal Agriculture Coalition, and the Michigan Agriculture Experiment Station. The authors are grateful to Dr. Sandra Velleman for the donation of turkey breast muscle from 18-day embryo, 1-day post hatch poult, and 16-week post hatch turkey.
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