title: Morphogenesis and cell fate determination within the adaxial cell equivalence group of the zebrafish myotome.
abstract: One of the central questions of developmental biology is how cells of equivalent potential-an equivalence group-come to adopt specific cellular fates. In this study we have used a combination of live imaging, single cell lineage analyses, and perturbation of specific signaling pathways to dissect the specification of the adaxial cells of the zebrafish embryo. We show that the adaxial cells are myogenic precursors that form a cell fate equivalence group of approximately 20 cells that consequently give rise to two distinct sub-types of muscle fibers: the superficial slow muscle fibers (SSFs) and muscle pioneer cells (MPs), distinguished by specific gene expression and cell behaviors. Using a combination of live imaging, retrospective and indicative fate mapping, and genetic studies, we show that MP and SSF precursors segregate at the beginning of segmentation and that they arise from distinct regions along the anterior-posterior (AP) and dorsal-ventral (DV) axes of the adaxial cell compartment. FGF signaling restricts MP cell fate in the anterior-most adaxial cells in each somite, while BMP signaling restricts this fate to the middle of the DV axis. Thus our results reveal that the synergistic actions of HH, FGF, and BMP signaling independently create a three-dimensional (3D) signaling milieu that coordinates cell fate within the adaxial cell equivalence group.
authors.affiliation: Australian Regenerative Medicine Institute, Monash University, Clayton, Australia.
authors.forename: Mai E
authors.initials: ME
authors.lastname: Nguyen-Chi
authors.forename: Robert
authors.initials: R
authors.lastname: Bryson-Richardson
authors.forename: Carmen
authors.initials: C
authors.lastname: Sonntag
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Hall
authors.forename: Abigail
authors.initials: A
authors.lastname: Gibson
authors.forename: Tamar
authors.initials: T
authors.lastname: Sztal
authors.forename: Wendy
authors.initials: W
authors.lastname: Chua
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Schilling
authors.forename: Peter D
authors.initials: PD
authors.lastname: Currie
mesh_terms: D000818:Animals; D001483:Base Sequence; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D002454:Cell Differentiation; D005346:Fibroblast Growth Factors / Q000378:metabolism; D055785:Gene Knockdown Techniques; D055431:Growth Differentiation Factor 6 / Q000378:metabolism; D053823:Hedgehog Proteins / Q000378:metabolism; D009024:Morphogenesis / Q000235:genetics; D018657:Muscle Fibers, Slow-Twitch / Q000166:cytology* / Q000378:metabolism*; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism; D015027:Zebrafish / Q000235:genetics* / Q000378:metabolism*; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D019485:Bone Morphogenetic Proteins; D055431:Growth Differentiation Factor 6; D053823:Hedgehog Proteins; D009419:Nerve Tissue Proteins; D029961:Zebrafish Proteins; C420987:gdf6a protein, zebrafish; C434248:spry4 protein, zebrafish; D005346:Fibroblast Growth Factors