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The ryanodine receptor/calcium channel genes are widely and differentially expressed in murine brain and peripheral
G Giannini1, A Conti, S Mammarella
1European Molecular Biology Laboratory, Heidelberg, Germany.
Abstract:
Ryanodine receptors (RyRs) are intracellular calcium release channels that participate in controlling cytosolic calcium levels. At variance with the probably ubiquitous inositol 1,4,5-trisphosphate-operated calcium channels (1,4,5-trisphosphate receptors), RyRs have been mainly regarded as the calcium release channels controlling skeletal and cardiac muscle contraction. Increasing evidence has recently suggested that RyRs may be more widely expressed, but this has never been extensively examined. Therefore, we cloned three cDNAs corresponding to murine RyR homologues to carry a comprehensive analysis of their expression in murine tissues. Here, we report that the three genes are expressed in almost all tissues analyzed, where tissue-specific patterns of expression were observed. In the uterus and vas deferens, expression of RyR3 was localized to the smooth muscle component of these organs. In the testis, expression of RyR1 and RyR3 was detected in germ cells. RyR mRNAs were also detected in in vitro-cultured cell lines. RyR1, RyR2, and RyR3 mRNA were detected in the cerebrum and in the cerebellum. In situ analysis revealed a cell type-specific pattern of expression in the different regions of the central nervous system. The differential expression of the three ryanodine receptor genes in the central nervous system was also confirmed using specific antibodies against the respective proteins. This widespread pattern of expression suggests that RyRs may participate in the regulation of intracellular calcium homeostasis in a range of cells wider than previously recognized.
Insights
Ryanodine receptors (RyRs) are calcium channels found in nearly all mouse tissues, not just muscles. This widespread expression suggests RyRs play a broader role in cellular calcium regulation than previously understood.
Area of Science:
- Molecular Biology
- Cellular Physiology
- Neuroscience
Background:
- Ryanodine receptors (RyRs) are critical intracellular calcium release channels.
- While primarily known for muscle contraction, RyRs' broader expression was under-investigated.
- Inositol 1,4,5-trisphosphate receptors are ubiquitous calcium channels, distinct from RyRs.
Purpose of the Study:
- To comprehensively analyze the expression patterns of three murine ryanodine receptor (RyR) homologues.
- To investigate the tissue-specific distribution of RyR1, RyR2, and RyR3 in mice.
- To determine if RyRs are expressed beyond muscle tissues.
Main Methods:
- Cloning of three murine RyR cDNAs.
- Analysis of RyR gene expression across various murine tissues.
- In situ hybridization and antibody-based detection in the central nervous system.
Main Results:
- All three RyR genes (RyR1, RyR2, RyR3) showed expression in almost all analyzed murine tissues.
- Tissue-specific expression patterns were observed, including in the uterus, vas deferens, testis germ cells, and cell lines.
- RyR mRNA and protein were detected in the cerebrum and cerebellum, with cell-type specific patterns in the CNS.
Conclusions:
- Murine RyRs exhibit a far more widespread tissue distribution than previously recognized.
- The diverse expression suggests RyRs are involved in regulating intracellular calcium homeostasis in numerous cell types.
- This broad expression profile opens new avenues for understanding RyR function in various physiological processes.