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Science 12 July 1991:
Vol. 253. no. 5018, pp. 435 - 438
DOI: 10.1126/science.253.5018.435
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Articles

Conversion of Ectoderm to Mesoderm by Cytoplasmic Extrusion in Leech Embryos

BRAD H. NELSON 1 and DAVID A. WEISBLAT 2

1 Graduate Group in Neurobiology, University of California, Berkeley, CA 94720
2 Graduate Group in Neurobiology and Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720

The role of cytoplasmic domains in the determination of the fates of ectodermal and mesodermal cells has been investigated in leech embryos. When yolk-deficient cytoplasm (teloplasm) was extruded from the animal pole of the zygote, the ectodermal precursor blastomere was converted to a mesodermal fate. This change of fate can be prevented by replacement of the extruded animal teloplasm with teloplasm from the vegetal pole. The fate of the mesodermal precursor blastomere was unaffected by teloplasm extrusion or rearrangement. These results demonstrate that ectodermal and mesodermal determination offate involves a binary decision dependent on the position of teloplasm along the animal-vegetal axis.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Mechanisms of elongation in embryogenesis.
R. Keller (2006)
Development 133, 2291-2302
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Changes in Gene Expression at the Precursor -> Stem Cell Transition in Leech.
K. A. Hohenstein and D. H. Shain (2004)
Stem Cells 22, 514-521
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A nanos homolog in leech.
M Pilon and D. Weisblat (1997)
Development 124, 1771-1780
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Unequal cleavage in leech embryos: zygotic transcription is required for correct spindle orientation in subset of early blastomeres.
S. Bissen and C. Smith (1996)
Development 122, 599-606
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Science. ISSN 0036-8075 (print), 1095-9203 (online)