title: Axolotls with an under- or oversupply of neural crest can regulate the sizes of their dorsal root ganglia to normal levels.
abstract: How animals adjust the size of their organs is a fundamental, enduring question in biology. Here we manipulate the amount of neural crest (NC) precursors for the dorsal root ganglia (DRG) in axolotl. We produce embryos with an under- or over-supply of pre-migratory NC in order to find out if DRG can regulate their sizes during development. Axolotl embryos are perfectly suitable for this research. Firstly, they are optimal for microsurgical manipulations and tissue repair. Secondly, they possess, unlike most other vertebrates, only one neural crest string located on top of the neural tube. This condition and position enables NC cells to migrate to either side of the embryo and participate in the regulation of NC cell distribution. We show that size compensation of DRG in axolotl occurs in 2 cm juveniles after undersupply of NC (up-regulation) and in 5 cm juveniles after oversupply of NC (down-regulation). The size of DRG is likely to be regulated locally within the DRG and not via adaptations of the pre-migratory NC or during NC cell migration. Ipsi- and contralateral NC cell migration occurs both in embryos with one and two neural folds, and contralateral migration of NC is the only source for contralateral DRG formation in embryos with only one neural fold. Compensatory size increase is accompanied by an increase in cell division of a DRG precursor pool (PCNA+/SOX2-), rather than by DRG neurons or glial cells. During compensatory size decrease, increased apoptosis and reduced proliferation of DRG cells are observed.
authors.affiliation: Center for Regenerative Therapies Dresden (CRTD), Technische Universität Dresden, Fetscherstrasse 105, 01307 Dresden, Germany.
authors.forename: Ana
authors.initials: A
authors.lastname: Zarzosa
authors.affiliation: University of Münster, Angiogenesis Laboratory, Röntgenstr. 20, 48149 Münster, Germany.
authors.forename: Kathrin
authors.initials: K
authors.lastname: Grassme
authors.affiliation: Center for Regenerative Therapies Dresden (CRTD), Technische Universität Dresden, Fetscherstrasse 105, 01307 Dresden, Germany.
authors.forename: Elly
authors.initials: E
authors.lastname: Tanaka
authors.affiliation: Center for Regenerative Therapies Dresden (CRTD), Technische Universität Dresden, Fetscherstrasse 105, 01307 Dresden, Germany; Department of Anatomy, Technische Universität, Dresden, Fetscherstrasse 74, 01307 Dresden, Germany.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Taniguchi
authors.affiliation: Department of Anatomy, Technische Universität, Dresden, Fetscherstrasse 74, 01307 Dresden, Germany.
authors.forename: Silvia
authors.initials: S
authors.lastname: Bramke
authors.affiliation: Center for Regenerative Therapies Dresden (CRTD), Technische Universität Dresden, Fetscherstrasse 105, 01307 Dresden, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Kurth
authors.affiliation: Center for Regenerative Therapies Dresden (CRTD), Technische Universität Dresden, Fetscherstrasse 105, 01307 Dresden, Germany; Department of Anatomy, Technische Universität, Dresden, Fetscherstrasse 74, 01307 Dresden, Germany. Electronic address: hans-henning.epperlein@tu-dresden.de.
authors.forename: Hans
authors.initials: H
authors.lastname: Epperlein
mesh_terms: D000558:Ambystoma mexicanum; D000818:Animals; D017209:Apoptosis; D019521:Body Patterning; D002455:Cell Division; D002465:Cell Movement; D005727:Ganglia, Spinal / Q000033:anatomy & histology* / Q000196:embryology*; D049452:Green Fluorescent Proteins; D009432:Neural Crest / Q000196:embryology*; D055495:Neurogenesis / Q000502:physiology; D009929:Organ Size / Q000502:physiology; D018809:Proliferating Cell Nuclear Antigen / Q000096:biosynthesis; D055748:SOXB1 Transcription Factors / Q000096:biosynthesis
chemical_list: D018809:Proliferating Cell Nuclear Antigen; D055748:SOXB1 Transcription Factors; D049452:Green Fluorescent Proteins
keywords: Axolotl; Dorsal root ganglia; Neural crest; Neural fold grafting; Size control