Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1988-5-31
pubmed:abstractText
The body plan of Xenopus laevis can be respecified by briefly exposing early cleavage stage embryos to lithium. Such embryos develop exaggerated dorsoanterior structures such as a radial eye and cement gland (K.R. Kao, Y. Masui, and R.P. Elinson, 1986, Nature (London) 322, 371-373). In this paper, we demonstrate that the enhanced dorsoanterior phenotype results from an overcommitment of mesoderm to dorsoanterior mesoderm. Histological and immunohistochemical observations reveal that the embryos have a greatly enlarged notochord with very little muscle tissue. In addition, they develop a radial, beating heart, suggesting that lithium also specifies anterior mesoderm and pharyngeal endoderm. Randomly oriented diametrically opposed marginal zone grafts from lithium-treated embryos, when transplanted into ultraviolet (uv)-irradiated axis-deficient hosts, rescue dorsal axial structures. These transplantation experiments demonstrate that the entire marginal zone of the early gastrula consists of presumptive dorsal mesoderm. Vital dye marking experiments also indicate that the entire marginal zone maps to the prominent proboscis that is composed of chordamesoderm and represents the long axis of the embryo. These results suggest that lithium respecifies the mesoderm of Xenopus laevis embryos so that it differentiates into the Spemann organizer. We suggest that the origin of the dorsoanterior enhanced phenotypes generated by lithium and the dorsoanterior deficient phenotypes generated by uv irradiation are due to relative quantities of organizer. Our evidence demonstrates the existence of a continuum of body plan phenotypes based on this premise.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0012-1606
pubmed:author
pubmed:issnType
Print
pubmed:volume
127
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
64-77
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1988
pubmed:articleTitle
The entire mesodermal mantle behaves as Spemann's organizer in dorsoanterior enhanced Xenopus laevis embryos.
pubmed:affiliation
Department of Zoology, University of Toronto, Ontario, Canada.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't