PUBLICATION

Metameric relationship of the somitic sclerotome to elements of the peripheral nervous system and the vertebral column during zebrafish development

Authors
Morin-Kensicki, E.M.
ID
ZDB-PUB-021016-99
Date
1994
Source
Ph.D. Thesis : (Thesis)
Registered Authors
Morin-Kensicki, Elizabeth M.
Keywords
none
MeSH Terms
none
PubMed
none
Abstract
Vertebrate embryos display metameric patterns in many trunk tissues, including somites, elements of the peripheral nervous system (PNS), and the vertebral column. The developmental relationships that exist among segmental structures and how the metameric patterns are established are not well understood. In this study, I characterize the development of one somite derivative, sclerotome, study its role in the segmental patterning of PNS structures, and examine its relationship to vertebral column segmentation in the zebrafish. Intracellular injection of individual somitic cells with vital fluorescent dyes revealed the following details of sclerotomal development: (1) an origin from the ventromedial region of each somite in a rostral to caudal sequence along the length of the embryo, (2) rostrocaudal differences in time and path of migration within each segment, (3) posterior sclerotomal cells with muscle cell siblings, and (4) migration to locations consistent with expected derivatives. To test the role of sclerotome in PNS patterning, I ablated premigratory sclerotome by aspiration and observed motoneuronal outgrowth and dorsal root ganglion (DRG) formation. The outgrowth of an identified primary motoneuron was affected in about one third of experimental segments, however, the segmental pattern of dorsal and ventral motor nerves was not discernably affected. In addition, removal of sclerotome did not appear to disrupt development of segmental DRGs. From these results and results from work of others in avian embryos, I propose the following model: PNS segmentation is established through interactions with the adjacent paraxial mesoderm which may develop as sclerotome or myotome in different vertebrate species. To investigate how the segmental pattern of the vertebral column develops displaced from the metameric register of the somites, I studied vertebral development and the relative distribution of the progeny of single labeled sclerotomal cells. I found that single cells contributed progeny to vertebral locations rostral and/or caudal to their somite of origin regardless of their initial position within the somite, contrary to current models of resegmentation. These results suggest that the establishment of proper segmental pattern within the vertebral column is not the result of recombining half sclerotomes but rather may be a more complex patterning event.
Errata / Notes
Ph.D. Thesis, University of Oregon
Genes / Markers
Figures
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
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Orthology
Engineered Foreign Genes
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