title: Hsp47 mediates Cx43-dependent skeletal growth and patterning in the regenerating fin.
abstract: Skeletal morphogenesis describes how bones achieve their correct shape and size and appropriately position joints. We use the regenerating caudal fin of zebrafish to study this process. Our examination of the fin length mutant short fin (sof (b123)) has revealed that the gap junction protein Cx43 is involved in skeletal morphogenesis by promoting cell proliferation and inhibiting joint formation, thereby coordinating skeletal growth and patterning. Here we demonstrate that serpinh1b is molecularly and functionally downstream of cx43. The gene serpinh1b codes for a protein called Hsp47, a molecular chaperone responsible for proper folding of procollagen molecules. Knockdown of Hsp47 in regenerating fins recapitulates the sof (b123) phenotypes of reduced fin length, reduced segment length and reduced level of cell proliferation. Furthermore, Hsp47 knockdown affects the organization and localization of the collagen-based actinotrichia. Together, our findings reveal that serpinh1b acts in a cx43 dependent manner to regulate cell proliferation and joint formation. We conclude that disruption of the collagen-based extracellular matrix influences signaling events required for cell proliferation, as well as the patterning of skeletal precursor cells that influences segment length. Therefore, we suggest that Hsp47 function is necessary for skeletal growth and patterning during fin regeneration.
authors.affiliation: Department of Biological Sciences, Lehigh University, United States.
authors.forename: Joyita
authors.initials: J
authors.lastname: Bhadra
authors.affiliation: Department of Biological Sciences, Lehigh University, United States. Electronic address: mki3@lehigh.edu.
authors.forename: M Kathryn
authors.initials: MK
authors.lastname: Iovine
mesh_terms: D058500:Animal Fins / Q000254:growth & development* / Q000502:physiology*; D000818:Animals; D030801:Animals, Genetically Modified; D019521:Body Patterning / Q000235:genetics / Q000502:physiology; D001846:Bone Development / Q000235:genetics / Q000502:physiology; D049109:Cell Proliferation; D018031:Connexin 43 / Q000235:genetics / Q000502:physiology*; D055785:Gene Knockdown Techniques; D050958:HSP47 Heat-Shock Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D017403:In Situ Hybridization; D008954:Models, Biological; D009154:Mutation; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012038:Regeneration / Q000235:genetics / Q000502:physiology; D015398:Signal Transduction; D015027:Zebrafish / Q000235:genetics / Q000254:growth & development* / Q000502:physiology*; D029961:Zebrafish Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*
chemical_list: D018031:Connexin 43; D050958:HSP47 Heat-Shock Proteins; D012333:RNA, Messenger; D029961:Zebrafish Proteins; C494659:hsp47 protein, zebrafish
keywords: Cell proliferation; Gap junction; Joint formation; Zebrafish; short fin