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Blastomeres show differential fate changes in 8-cell Xenopus laevis embryos that are rotated 90 degrees before first cleavageTo study the mechanisms of dorsal axis specification, the alteration in dorsal cell fate of cleavage stage blastomeres in axis-respecified Xenopus laevis embryos was investigated. Fertilized eggs were rotated 90 degrees with the sperm entry point up or down with respect to the gravitational field. At the 8-cell stage, blastomeres were injected with the lineage tracers, Texas Red- or FITC-Dextran Amines. The distribution of the labeled progeny was mapped at the tail-bud stages (stages 35-38) and compared with the fate map of an 8-cell embryo raised in a normal orientation. As in the normal embryos, each blastomere in the rotated embryos has a characteristic and predictable cell fate. After 90 degrees rotation the blastomeres in the 8-cell stage embryo roughly switched their position by 90 degrees, but the fate of the blastomeres did not simply show a 90 degrees switch appropriate for their new location. Four types of fate change were observed: (i) the normal fate of the blastomere is conserved with little change; (ii) the normal fate is completely changed and a new fate is adopted according to the blastomere's new position: (iii) the normal fate is completely changed, but the new fate is not appropriate for its new position; and (4) the blastomere partially changed its fate and the new fate is a combination of its original fate and a fate appropriate to its new location. According to the changed fates, the blastomeres that adopt dorsal fates were identified in rotated embryos. This identification of dorsal blastomeres provides basic important information for further study of dorsal signaling in Xenopus embryos.
Document ID
20040172715
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Huang, S.
(The George Washington University Medical Center Washington, DC 20037, United States)
Johnson, K. E.
Wang, H. Z.
Date Acquired
August 22, 2013
Publication Date
April 1, 1998
Publication Information
Publication: Development, growth & differentiation
Volume: 40
Issue: 2
ISSN: 0012-1592
Subject Category
Life Sciences (General)
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Developmental Biology
Non-NASA Center

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