TY - JOUR TI - Segmentation of the zebrafish axial skeleton relies on notochord sheath cells and not on the segmentation clock AU - Lleras Forero, Laura AU - Narayanan, Rachna AU - Huitema, Leonie FA AU - VanBergen, Maaike AU - Apschner, Alexander AU - Peterson-Maduro, Josi AU - Logister, Ive AU - Valentin, Guillaume AU - Morelli, Luis G AU - Oates, Andrew C AU - Schulte-Merker, Stefan A2 - Whitfield, Tanya T. VL - 7 PY - 2018 DA - 2018/04/06 SP - e33843 C1 - eLife 2018;7:e33843 DO - 10.7554/eLife.33843 UR - https://doi.org/10.7554/eLife.33843 AB - Segmentation of the axial skeleton in amniotes depends on the segmentation clock, which patterns the paraxial mesoderm and the sclerotome. While the segmentation clock clearly operates in teleosts, the role of the sclerotome in establishing the axial skeleton is unclear. We severely disrupt zebrafish paraxial segmentation, yet observe a largely normal segmentation process of the chordacentra. We demonstrate that axial entpd5+ notochord sheath cells are responsible for chordacentrum mineralization, and serve as a marker for axial segmentation. While autonomous within the notochord sheath, entpd5 expression and centrum formation show some plasticity and can respond to myotome pattern. These observations reveal for the first time the dynamics of notochord segmentation in a teleost, and are consistent with an autonomous patterning mechanism that is influenced, but not determined by adjacent paraxial mesoderm. This behavior is not consistent with a clock-type mechanism in the notochord. KW - notochord KW - somitogenesis clock KW - somite KW - Entpd5 JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -