|
|
|
|
|
|
|
||||
| Home Help Feedback Subscriptions Archive Search Table of Contents | ||||
Development, Vol 121, Issue 5 1497-1505, Copyright © 1995 by Company of Biologists
JOURNAL ARTICLES |
AH Wikramanayake, BP Brandhorst and WH Klein
Department of Biochemistry and Molecular Biology, University of Texas, Houston 77030, USA.
During early embryogenesis, the highly regulative sea urchin embryo relies extensively on cell-cell interactions for cellular specification. Here, the role of cellular interactions in the temporal and spatial expression of markers for oral and aboral ectoderm in Strongylocentrotus purpuratus and Lytechinus pictus was investigated. When pairs of mesomeres or animal caps, which are fated to give rise to ectoderm, were isolated and cultured they developed into ciliated embryoids that were morphologically polarized. In animal explants from S. purpuratus, the aboral ectoderm-specific Spec1 gene was activated at the same time as in control embryos and at relatively high levels. The Spec1 protein was restricted to the squamous epithelial cells in the embryoids suggesting that an oral-aboral axis formed and aboral ectoderm differentiation occurred correctly. However, the Ecto V protein, a marker for oral ectoderm differentiation, was detected throughout the embryoid and no stomodeum or ciliary band formed. These results indicated that animal explants from S. purpuratus were autonomous in their ability to form an oral-aboral axis and to differentiate aboral ectoderm, but other aspects of ectoderm differentiation require interaction with vegetal blastomeres. In contrast to S. purpuratus, aboral ectoderm-specific genes were not expressed in animal explants from L. pictus even though the resulting embryoids were morphologically very similar to those of S. purpuratus. Recombination of the explants with vegetal blastomeres or exposure to the vegetalizing agent LiCl restored activity of aboral ectoderm-specific genes, suggesting the requirement of a vegetal induction for differentiation of aboral ectoderm cells.(ABSTRACT TRUNCATED AT 250 WORDS)
This article has been cited by other articles:
|
|
 |
|
  R. Range, F. Lapraz, M. Quirin, S. Marro, L. Besnardeau, and T. Lepage Cis-regulatory analysis of nodal and maternal control of dorsal-ventral axis formation by Univin, a TGF-{beta} related to Vg1 Development, October 15, 2007; 134(20): 3649 - 3664. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. A. Bradham and D. R. McClay p38 MAPK is essential for secondary axis specification and patterning in sea urchin embryos Development, January 1, 2006; 133(1): 21 - 32. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. M. Gross, R. E. Peterson, S.-Y. Wu, and D. R. McClay LvTbx2/3: a T-box family transcription factor involved in formation of the oral/aboral axis of the sea urchin embryo Development, May 1, 2003; 130(9): 1989 - 1999. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Fuchikami, K. Mitsunaga-Nakatsubo, S. Amemiya, T. Hosomi, T. Watanabe, D. Kurokawa, M. Kataoka, Y. Harada, N. Satoh, S. Kusunoki, et al. T-brain homologue (HpTb) is involved in the archenteron induction signals of micromere descendant cells in the sea urchin embryo Development, March 13, 2003; 129(22): 5205 - 5216. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Sweet, P. Hodor, and C. Ettensohn The role of micromere signaling in Notch activation and mesoderm specification during sea urchin embryogenesis Development, January 12, 1999; 126(23): 5255 - 5265. [Abstract] [PDF]
|
|
|
|
 |
|
 A. H. Wikramanayake, L. Huang, and W. H. Klein beta -Catenin is essential for patterning the maternally specified animal-vegetal axis in the sea urchin embryo PNAS, August 4, 1998; 95(16): 9343 - 9348. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Davidson, R. Cameron, and A Ransick Specification of cell fate in the sea urchin embryo: summary and some proposed mechanisms Development, January 9, 1998; 125(17): 3269 - 3290. [Abstract] [PDF]
|
|
|
|
|
|
R. Ramachandran, A. Wikramanayake, J. Uzman, V Govindarajan, and C. Tomlinson Disruption of gastrulation and oral-aboral ectoderm differentiation in the Lytechinus pictus embryo by a dominant/negative PDGF receptor Development, January 6, 1997; 124(12): 2355 - 2364. [Abstract] [PDF]
|
|
|
|
|
|
A. Wikramanayake and W. Klein Multiple signaling events specify ectoderm and pattern the oral-aboral axis in the sea urchin embryo Development, January 1, 1997; 124(1): 13 - 20. [Abstract] [PDF]
|
|
|
|
|
|
C Ghiglione, F Emily-Fenouil, P Chang, and C Gache Early gene expression along the animal-vegetal axis in sea urchin embryoids and grafted embryos Development, January 10, 1996; 122(10): 3067 - 3074. [Abstract] [PDF]
|
|
|
|
|
|
C. Mao, A. Wikramanayake, L Gan, C. Chuang, R. Summers, and W. Klein Altering cell fates in sea urchin embryos by overexpressing SpOtx, an orthodenticle-related protein Development, January 5, 1996; 122(5): 1489 - 1498. [Abstract] [PDF]
|
|
