Genome-wide expression analysis of satellite cells

(Abstract of publication submitted currently) To clarify molecular regulation of satellite cells, we performed genome-wide gene expression analysis of quiescent satellite cells isolated from mouse skeletal muscle by flow cytometry. We identified 53 novel quiescent satellite cell-specific genes whose expressions are sharply down-regulated upon activation. The gene list contains a number of cell surface molecules, transcriptional factors, and cytokines and other signal transduction molecules. We further confirmed that Odz4 and calcitonin receptor proteins were expressed by quiescent but not by activated satellite cells in vivo. Importantly, we found that Pax7+/calcitonin receptor+ satellite cells reappear in close association with regenerating myofibers 7 days after muscle damage, often outside the basal lamina. Moreover, an agonist of calcitonin receptor suppressed the activation of quiescent satellite cells on myofibers in in vitro culture, suggesting that calcitonin receptor signaling plays an important role in renewal and maintenance of satellite cells. Our results show the gene expression profile of quiescent satellite cells for the first time and reveal the temporal and spatial reappearance of a satellite cell pool. Keywords: cell type comparison Satellite cells and non-satellite cells were examined. Totally three types of cells (groups), the satellite cells in quiescent and activated states and the non-satellite cells, were compared. Each has 4 replicates.