activation of pax7-positive cells in a non-contractile tissue contributes to regeneration of myogenic tissues in the electric fish s. macrurusnon-contractile组织有助于激活pax7-positive细胞再生的肌原性的组织美国macrurus电鱼.pdfVIP

Activation of Pax7-Positive Cells in a Non-Contractile Tissue Contributes to Regeneration of Myogenic Tissues in the Electric Fish S. macrurus 1¤ 2 3 1 Christopher M. Weber , Mark Q. Martindale , Stephen J. Tapscott , Graciela A. Unguez * 1 Biology Department, New Mexico State University, Las Cruces, New Mexico, United States of America, 2 Kewalo Marine Lab, University of Hawaii, Honolulu, Hawaii, United States of America, 3 Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America Abstract The ability to regenerate tissues is shared across many metazoan taxa, yet the type and extent to which multiple cellular mechanisms come into play can differ across species. For example, urodele amphibians can completely regenerate all lost tissues, including skeletal muscles after limb amputation. This remarkable ability of urodeles to restore entire limbs has been largely linked to a dedifferentiation-dependent mechanism of regeneration. However, whether cell dedifferentiation is the fundamental factor that triggers a robust regeneration capacity, and whether the loss or inhibition of this process explains the limited regeneration potential in other vertebrates is not known. Here, we studied the cellular mechanisms underlying the repetitive regeneration of myogenic tissues in the electric fish S. macrurus. Our in vivo microinjection studies of high molecular weight cell lineage tracers into single identified adult myogenic cells (muscle or noncontractile muscle-derived electrocytes) revealed no fragmentation or cellularization proximal to the amputation plane. In contrast, ultrastructural and immunolabeling studies verified the presence of myogenic stem cells that express the satellite cell marker Pa