Neural-inducing activity of newly mesodermalized ectoderm

Suzuki, Akio; Yoshimura, Yumiko; Yano, Yumihiko

doi:10.1007/bf02439434

Cited by 11 publications

(6 citation statements)

References 28 publications

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“…The present study indicated that noggin was activated between 6 h and 12 h during mesodermalization of the ectoderm. In our previous study (Suzuki et al 1986), it was indicated that the mE acquired the neural‐inducing activity during the first 12 h of its mesodermalization. In normal X. laevis embryogenesis, noggin is expressed dominantly in the dorsal marginal zone at early gastrula and then expression is activated in the notochord of the advanced embryo (Smith & Harland 1992).…”

Section: Discussionmentioning

confidence: 93%

“…Most mE cells differentiate into axial mesoderm, notochord and muscle (Kawakami 1976; Suzuki et al 1986). The present study confirmed that mE had the organizer property of being able to induce a secondary axis with well‐differentiated chordamesoderm and neural tissues.…”

Section: Discussionmentioning

confidence: 99%

“…Suzuki et al (1986) have found that when the presumptive ectoderm of the early Cynops pyrrhogaster gastrula is artificially mesodermalized by the Carassius carassius swim bladder, it acquires the organizer property; namely, it is capable of axial mesodermal differentiation and neural‐inducing activity. It has been suggested that such mesodermalized ectoderm may be useful as a Spemann’s organizer model.…”

Section: Introductionmentioning

confidence: 99%

“…It is during the early phase of gastrulation that the organizer property of the dorsal marginal zone, which is associated with its mesodermalization, is established (Kaneda 1981;Kaneda & Suzuki 1983;Grunz 1993). Suzuki et al (1986) have found that when the presumptive ectoderm of the early Cynops pyrrhogaster gastrula is artificially mesodermalized by the Carassius carassius swim bladder, it acquires the organizer property; namely, it is capable of axial mesodermal differentiation and neural-inducing activity. It has been suggested that such mesodermalized ectoderm may be useful as a Spemann's organizer model.…”

Section: Introductionmentioning

confidence: 99%

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Comparative study of sequential expression of the organizer‐related genes in normal Cynops pyrrhogaster embryos and mesodermalized ectoderm

Tabata

Sakaguchi²,

Tajima

et al. 2001

Dev Growth Differ

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An artificially mesodermalized ectoderm (mE) of early Cynops pyrrhogaster gastrula acquires the organizer property; the mE is able to induce the secondary axis. The expression of organizer-related genes was investigated during the mesodermalizing process of the mE. The expression of C. pyrrhogaster organizer-related genes, such as bra, gsc, lim-1, chd and noggin, were analyzed. Cynops pyrrhogaster shh expression was also investigated. The organizer-related genes were activated by 12 h after the mesoderm-inducing stimulus. It was noted that there was a temporal gap in the expression of each gene. The expression of bra and gsc seemed to be more quickly activated during the mesodermalizing process. While expression of lim-1 and noggin was activated later than that of bra and gsc, lim-1 expression was earlier than chd and noggin expression. Shh expression was activated later than lim-1/noggin. The present study suggests the possibility that the bra/gsc, lim-1, chd, noggin and shh genes are expressed one by one in that order during the mesodermalizing of the presumptive ectoderm. It also indicates that the sequence is not always consistent with that of the whole embryo during normal embryogenesis. The meaning of the discrepancy will be discussed in connection with the cascade of certain genes expressed during the mesodermalizing process.

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Section: Discussionmentioning

confidence: 93%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Comparative study of sequential expression of the organizer‐related genes in normal Cynops pyrrhogaster embryos and mesodermalized ectoderm

Tabata

Sakaguchi²,

Tajima

et al. 2001

Dev Growth Differ

Self Cite

View full text Add to dashboard Cite

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“…In the present study, differentiation of the ear vesicle and the spinal cord was always accompanied by notochord formation. It has been reported that mesodermalized ectoderm induces neural tissues as a secondary induction (Suzuki et al, 1986). It is likely that the caudalization of Con A-induced anterior CNS is caused by the dorsal mesoderm initially induced by activin A and Con A.…”

Section: Caudalizing Activity Of Activin a And Ramentioning

confidence: 99%

In vitroControl of Embryonic Axis Formation by Activin A, Concanavalin A, and Retinoic Acid in Xenopus laevis

et al. 1998

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We have demonstrated that the tissue differentiation patterns along the dorsoventral and anteroposterior axes can be controlled by a combination of activin A, concanavalin A (Con A), and retinoic acid. Xenopus blastula animal caps, normally fated to form epidermal tissues, differentiated into ventral mesoderm tissues such as coelomic epithelium and blood-like cells following treatment with activin A (0.5 ng/ ml). Dorsal mesoderm tissues like muscle and notochord, were induced by graded addition of Con A. Conversely, Con A (1 mg/ml) induced anterior neural tissues, forebrain accompanied by eyes and cement glands, in the animal caps. Posterior neural tissues, hindbrain with ear vesicles and spinal cord, were induced by graded addition of activin A. Retinoic acid was also capable of shifting the Con A-induced anterior neural tissues to more posterior tissue phenotypes, however, its caudalizing activity was slightly different from that of activin A. These results suggest that the concentration gradients of these three factors can regulate the differentiation patterns along the embryonic axes. The present study provides a suitable test system for analyzing the establishment of the fundamental body plan in early vertebrate development.

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Head and trunk-tail organizing effects of the gastrula ectoderm of Cynops pyrrhogaster after treatment with activin A

Ariizumi¹,

Asashima²

1995

Roux's Arch Dev Biol

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Differentiation tendency and the inducing ability of the presumptive ectoderm of newt early gastrulae were examined after treatment with activin A at a high concentration (100 ng/ml). The activin-treated ectoderm differentiated preferentially into yolk-rich endodermal cells. Combination explants consisting of three pieces of activin-treated ectoderm formed neural tissues and axial mesoderm along with endodermal cells. However, the neural tissue was poorly organized and never showed any central nervous system characteristics. When the activin-treated ectoderm was sandwiched between two sheets of untreated ectoderm, the sandwich explants differentiated into trunk-tail or head structures depending on the duration of preculture of activin-treated ectoderm in Holtfreter's solution. Short-term (0-5 h) precultured ectoderm induced trunk-tail structures accompanied by axial organs, alimentary canal and beating heart. The arrangement of the explant tissues and organs was similar to that of normal embryos. However, archencephalic structures, such as forebrain and eye, were lacking or deficient. On the other hand, long-term (10-25 h) precultured ectoderm induced archencephalic structures in addition to axial organs. Lineage analysis of the sandwich explants using fluorescent dyes revealed that the activin-treated ectoderm mainly differentiated into endodermal cells and induced axial mesoderm and central nervous system in the untreated ectoderm. These results suggest that activin A is one of the substances involved in triggering endodermal differentiation and that the presumptive ectoderm induced to form endoderm displays "trunk-tail organizer" or "head organizer" effects, depending on the duration of preculture.

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Neural-inducing activity of newly mesodermalized ectoderm

Cited by 11 publications

References 28 publications

Comparative study of sequential expression of the organizer‐related genes in normal Cynops pyrrhogaster embryos and mesodermalized ectoderm

Comparative study of sequential expression of the organizer‐related genes in normal Cynops pyrrhogaster embryos and mesodermalized ectoderm

In vitroControl of Embryonic Axis Formation by Activin A, Concanavalin A, and Retinoic Acid in Xenopus laevis

Head and trunk-tail organizing effects of the gastrula ectoderm of Cynops pyrrhogaster after treatment with activin A

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