The Differentiation of Gastrula Ectoderm in Medium Conditioned by Axial Mesoderm

Niu, M. C.; Twitty, Victor C.

doi:10.1073/pnas.39.9.985

Cited by 143 publications

(20 citation statements)

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“…This argues that epithelial containment is not necessary to permit secreted inducing signals to achieve a sufficiently high concentration, as suggested by Niu and Twitty (1953). At the same time, we have also found that planar inductive signals are effective at an extended range.…”

Section: Discussionsupporting

confidence: 57%

Induction of neuronal differentiation by planar signals in Xenopus embryos

Sater

Steinhardt

Keller

1993

Developmental Dynamics

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The induction of the central nervous system in amphibian embryos is mediated both by early planar signals produced by mesoderm at the dorsal lip and later vertical signals emanating from the dorsal mesoderm after involution. We have examined the role and spatial extent of planar signals in the induction of neuronal differentiation. Planar explants that included only the deep layer of the dorsal marginal zone, comprising both the dorsal mesoderm and the contiguous dorsal ectoderm, were isolated at the beginning of gastrulation. After removal of the epithelial layer, explants were maintained in modified Danilchik's medium until mid-neurula stages, when they were transferred to modified Danilchik's medium + 0.1% bovine serum albumin and cultured on laminin. Neurite outgrowth occurred in 90% of these planar explants. In contrast, little or no neuronal differentiation occurred in either ventral planar explants or explants of ectoderm alone. Video analysis of cell movements shows that large-scale cell mixing does not occur between mesoderm cells and ectoderm cells in planar explants. Retrograde labelling of neuronal cell bodies indicates that cells throughout the ectoderm undergo neuronal differentiation; neurons also differentiate in cultures of distal ectoderm isolated at early neurula stages from planar explants prepared at the beginning of gastrulation. These observations indicate that planar signals act over an extended range to induce neuronal differentiation. The inductive capacity of vertical signals was examined by recombining animal caps from ultra-violet (UV) irradiated embryos with involuted mesoderm from normal midgastrula embryos. Differentiation of either neurons or anterior neural structures occurred in 73% of vertical recombinates. Our results demonstrate that planar signals from the dorsal lip of the blastopore are capable of inducing neuronal differentiation over a considerable distance in the absence of epithelial confinement, convergence and extension, and mixing between the mesoderm and ectoderm. o 1993 Wiley-Liss, Inc.

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Section: Discussionsupporting

confidence: 57%

Induction of neuronal differentiation by planar signals in Xenopus embryos

Sater

Steinhardt

Keller

1993

Developmental Dynamics

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“…In fact, neural induction could be obtained in ectoblast expiants cultured with organizer frag ments, but without direct contact [Niu and Twitty, 1953] and by interposition of mem brane filters between the interacting tissues in amphibian [Saxén et al, 1976;Toivonen, 1978] and avian gastrula [Gallera et al, 1968], Cell junctions are probably involved only in the following phase in which segrega tion of the different regions of the central nervous system is determined [Toivonen, 1978[Toivonen, , 1979.…”

Section: Discussionmentioning

confidence: 99%

Extracellular Materials and Determination of Neuroectoblast in Amphibian Gastrula

Sánchez¹,

Barbieri²

1988

Pathobiology

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The biological activity of the extracellular material (ECM) located in the dorsal and ventral regions of Bufo arenarum is assayed. Ectoblast cells were isolated and cultured with ECM taken from the embryonal regions. The epiblastic cells treated with dorsal ECM, mainly located at the interphase between the invaginating blastoporal lip and the overlying ectoblast differentiated morphologically into neural, mesenchyme and pigment cells. In contrast, control epiplastic cells, cultured either in salt solution or in ventral region ECM, differentiated into ciliated and secretory cell types. The results reported here provide evidence that the dorsal region ECM of the embryo can induce neural differentiation in indeterminate epiblastic cells.

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“…Rccipicnt eggs were prepared by activation and enucleation (16) followed by removal of the outer jelly coat. The transplantation was performed in Niu and Twitty's solution (17), following the procedure of Briggs and King (12 FIGURE ~ Control frog of mutant phenotype produced by fertilizing eggs obtained from burnsi frogs with sperm derived from burnsi males. X ~.…”

Section: Methodsmentioning

confidence: 99%