scholarly journals Correction: Corrigendum: The zebrafish dorsal axis is apparent at the four-cell stage

Nature ◽  
2012 ◽  
Vol 494 (7435) ◽  
pp. 130-130
Author(s):  
Aniket V. Gore ◽  
Shingo Maegawa ◽  
Albert Cheong ◽  
Patrick C. Gilligan ◽  
Eric S. Weinberg ◽  
...  
Keyword(s):  
Cell Stage ◽  
Dorsal Axis

The zebrafish dorsal axis is apparent at the four-cell stage

Nature ◽  
2005 ◽  
Vol 438 (7070) ◽  
pp. 1030-1035 ◽  
Author(s):  
Aniket V. Gore ◽  
Shingo Maegawa ◽  
Albert Cheong ◽  
Patrick C. Gilligan ◽  
Eric S. Weinberg ◽  
...  
Keyword(s):  
Cell Stage ◽  
Dorsal Axis

Autonomous differentiation of dorsal axial structures from an animal cap cleavage stage blastomere in Xenopus

Development ◽  
1991 ◽  
Vol 112 (4) ◽  
pp. 1103-1114 ◽  
Author(s):  
B.C. Gallagher ◽  
A.M. Hainski ◽  
S.A. Moody
Keyword(s):  
Original Position ◽  
Cleavage Stage ◽  
Cell Stage ◽  
Dorsal Midline ◽  
Developmental Program ◽  
Opposite Pole ◽  
Secondary Axis ◽  
Dorsal Axis ◽  
Exogenous Growth ◽  
Primary Axis

Dorsal or ventral blastomeres of the 16- and 32-cell stage animal hemisphere were labeled with a lineage dye and transplanted into the position of a ventral, vegetal midline blastomere. The donor blastomeres normally give rise to substantial amounts of head structures and central nervous system, whereas the blastomere which they replaced normally gives rise to trunk mesoderm and endoderm. The clones derived from the transplanted ventral blastomeres were found in tissues appropriate for their new position, whereas those derived from the transplanted dorsal blastomeres were found in tissues appropriate for their original position. The transplanted dorsal clones usually migrated into the host's primary axis (D1.1, 92%; D1.1.1, 69%; D1.1.2, 100%), and in many cases they also induced and populated a secondary axis (D1.1, 43%; D1.1.1, 67%; D1.1.2, 63%). Bilateral deletion of the dorsal blastomeres resulted in partial deficits of dorsal axial structures in the majority of cases, whereas deletions of ventral midline blastomeres did not. When the dorsal blastomeres were cultured as explants they elongated. Notochord and cement glands frequently differentiated in these explants. These studies show that the progeny of the dorsal, midline, animal blastomeres: (1) follow their normal lineage program to populate dorsal axial structures after the blastomere is transplanted to the opposite pole of the embryo; (2) induce and contribute to a secondary axis from their transplanted position in many embryos; (3) are important for the normal formation of the entire length of the dorsal axis; and (4) autonomously differentiate in the absence of exogenous growth factor signals. These data indicate that by the 16-cell stage, these blastomeres have received instructions regarding their fate, and they are intrinsically capable of carrying out some of their developmental program.

The vegetal determinants required for the Spemann organizer move equatorially during the first cell cycle

Development ◽  
1996 ◽  
Vol 122 (7) ◽  
pp. 2207-2214 ◽  
Author(s):  
M. Sakai
Keyword(s):  
Cell Cycle ◽  
Formation Process ◽  
Lithium Treatment ◽  
Axis Formation ◽  
Cell Stage ◽  
Spemann Organizer ◽  
Dorsal Axis ◽  
Vegetal Pole ◽  
Organizing Center ◽  
Cell Embryo

Embryos with no dorsal axis were obtained when more than 15% of the egg surface was deleted from the vegetal pole of the early 1-cell embryo of Xenopus laevis. The timing of the deletion in the first cell cycle was critical: dorsal-deficient embryos were obtained when the deletion began before time 0.5 (50% of the first cell cycle) whereas normal dorsal axis usually formed when the deletion was done later than time 0.8. The axis deficiency could be restored by lithium treatment and the injection of vegetal but not animal cytoplasm. Bisection of the embryo at the 2-cell stage, which is known to restore the dorsal structures in the UV-ventralized embryos, had no effect on the vegetal-deleted embryos. These results show clearly that, in Xenopus, (1) the dorsal determinants (DDs) localized in the vegetal pole region at the onset of development are necessary for dorsal axis development and (2) the DDs move from the vegetal pole to a subequatorial region where they are incorporated into gastrulating cells to form the future organizing center. A model for the early axis formation process in Xenopus is proposed.

Xenopus maternal RNAs from a dorsal animal blastomere induce a secondary axis in host embryos

Development ◽  
1992 ◽  
Vol 116 (2) ◽  
pp. 347-355 ◽  
Author(s):  
A.M. Hainski ◽  
S.A. Moody
Keyword(s):  
Gene Families ◽  
Similar Process ◽  
Axis Formation ◽  
Cell Stage ◽  
Dorsal Midline ◽  
Rna Molecules ◽  
Secondary Axis ◽  
Dorsal Axis ◽  
Stage Embryo ◽  
Maternal Determinants

The initial steps of dorsal axis formation are controlled by localized maternal determinants in Drosophila, and a similar process has been proposed in Xenopus. The present study demonstrates that there are axis-inducing RNA molecules located in a specific dorsal midline, animal blastomere (D1.1) of the 16-cell-stage embryo. This blastomere, although in the animal hemisphere at cleavage stages, populates most of the dorsal lip of the blastopore, the region of Spemann's organizer, during gastrulation, and is the major progenitor for dorsal mesodermal tissues. Cytosol from this blastomere causes ventral cells to take a more dorsal fate. RNA from this blastomere induces a secondary axis when injected into ventral blastomeres and restores the dorsal axis in UV-irradiated embryos. In Xenopus, activin beta B, goosecoid and Xwnt-8 RNAs can ectopically induce a dorsal axis; however, none is a maternal transcript. Therefore, the D1.1 blastomere probably contains dorsal determinant(s) that are either maternal members of these gene families, or other presently unknown molecule(s). Regardless of the identity of the determinant(s), this study presents the first indication that Xenopus maternal RNAs in the dorsal animal hemisphere are able to organize the dorsal axis.

Human Adenovirus Uptake by Preirnplantation Mouse Embryos

1972 ◽  
Vol 30 ◽  
pp. 268-269
Author(s):  
D. G. Chase ◽  
W. Winters ◽  
L. Piko
Keyword(s):  
Hela Cells ◽  
Human Adenovirus ◽  
Mouse Embryos ◽  
Equilibrium Density ◽  
Cell Stage ◽  
Virus Attachment ◽  
Preimplantation Mouse Embryos ◽  
Embryo Culture Medium ◽  
Preimplantation Mouse ◽  
Mouse Cells

Although the outlines of human adenovirus entry and uncoating in HeLa cells has been clarified in recent electron microscope studies, several details remain unclear or controversial. Furthermore, morphological features of early interactions of human adenovirus with non-permissive mouse cells have not been extensively documented. In the course of studies on the effects of human adenoviruses type 5 (AD-5) and type 12 on cultured preimplantation mouse embryos we have examined virus attachment, entry and uncoating. Here we present the ultrastructural findings for AD-5.AD-5 was grown in HeLa cells and purified by successive velocity gradient and equilibrium density gradient centrifugations in CsCl. After dialysis against PBS, virus was sedimented and resuspended in embryo culture medium. Embryos were placed in culture at the 2-cell stage in Brinster's medium.

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