Cloning, tissue distribution, subcellular localization and overexpression of murine histidine-rich Ca2+ binding protein

AbstractThe histidine-rich Ca2+ binding protein (HRC) resides in the sarcoplasmic reticulum of muscle and binds Ca2+. Since Ca2+ concentrations can regulate gene expression via calcineurin, the mouse homologue of HRC (mHRC) was isolated and characterized. mHRC was detected in muscle progenitor cells, in primary clonal thymic tumors and a tumor cell line, suggesting a broader role for mHRC than in Ca2+ storage during muscle contraction. mHRC was present in the perinuclear region of myoblasts. To examine if it can regulate gene expression, mHRC was overexpressed in cells differentiating into cardiac and skeletal muscle. mHRC had no effect on cardiogenesis or myogenesis. Therefore, if mHRC plays a role in the regulation of gene expression during cellular differentiation, it does not appear to be either rate-limiting or inhibitory