The role of the zebrafish nodal-related genes squint and cyclops in patterning of mesendoderm

Dougan, Scott T. and Warga, Rachel M. and Kane, Donald A. and Schier, Alexander F. and Talbot, William S.. (2003) The role of the zebrafish nodal-related genes squint and cyclops in patterning of mesendoderm. Development, 130 (9). pp. 1837-1851.

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Official URL: https://edoc.unibas.ch/74883/

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Nodal signals, a subclass of the TGFbeta superfamily of secreted factors, induce formation of mesoderm and endoderm in vertebrate embryos. We have examined the possible dorsoventral and animal-vegetal patterning roles for Nodal signals by using mutations in two zebrafish nodal-related genes, squint and cyclops, to manipulate genetically the levels and timing of Nodal activity. squint mutants lack dorsal mesendodermal gene expression at the late blastula stage, and fate mapping and gene expression studies in sqt(-/-); cyc(+/+) and sqt(-/-); cyc(+/-) mutants show that some dorsal marginal cells inappropriately form hindbrain and spinal cord instead of dorsal mesendodermal derivatives. The effects on ventrolateral mesendoderm are less severe, although the endoderm is reduced and muscle precursors are located nearer to the margin than in wild type. Our results support a role for Nodal signals in patterning the mesendoderm along the animal-vegetal axis and indicate that dorsal and ventrolateral mesoderm require different levels of squint and cyclops function. Dorsal marginal cells were not transformed toward more lateral fates in either sqt(-/-); cyc(+/-) or sqt(-/-); cyc(+/+) embryos, arguing against a role for the graded action of Nodal signals in dorsoventral patterning of the mesendoderm. Differential regulation of the cyclops gene in these cells contributes to the different requirements for nodal-related gene function in these cells. Dorsal expression of cyclops requires Nodal-dependent autoregulation, whereas other factors induce cyclops expression in ventrolateral cells. In addition, the differential timing of dorsal mesendoderm induction in squint and cyclops mutants suggests that dorsal marginal cells can respond to Nodal signals at stages ranging from the mid-blastula through the mid-gastrula.
Faculties and Departments:05 Faculty of Science > Departement Biozentrum > Growth & Development > Cell and Developmental Biology (Schier)
UniBasel Contributors:Schier, Alexander F
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:Company of Biologists
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:06 Nov 2020 13:32
Deposited On:06 Nov 2020 13:32

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