期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1998
卷号：95
期号：16
页码：9343-9348
DOI：10.1073/pnas.95.16.9343
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：In sea urchin embryos, the animal-vegetal axis is specified during oogenesis. After fertilization, this axis is patterned to produce five distinct territories by the 60-cell stage. Territorial specification is thought to occur by a signal transduction cascade that is initiated by the large micromeres located at the vegetal pole. The molecular mechanisms that mediate the specification events along the animal-vegetal axis in sea urchin embryos are largely unknown. Nuclear {beta}-catenin is seen in vegetal cells of the early embryo, suggesting that this protein plays a role in specifying vegetal cell fates. Here, we test this hypothesis and show that {beta}-catenin is necessary for vegetal plate specification and is also sufficient for endoderm formation. In addition, we show that {beta}-catenin has pronounced effects on animal blastomeres and is critical for specification of aboral ectoderm and for ectoderm patterning, presumably via a noncell-autonomous mechanism. These results support a model in which a Wnt-like signal released by vegetal cells patterns the early embryo along the animal-vegetal axis. Our results also reveal similarities between the sea urchin animal-vegetal axis and the vertebrate dorsal-ventral axis, suggesting that these axes share a common evolutionary origin.
