TY - JOUR
T1 - β-Catenin is essential for patterning the maternally specified animal-vegetal axis in the sea urchin embryo
AU - Wikramanayake, Athula H.
AU - Huang, Ling
AU - Klein, William H.
PY - 1998/8/4
Y1 - 1998/8/4
N2 - 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 β-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 β-catenin is necessary for vegetal plate specification and is also sufficient for endoderm formation. In addition, we show that β-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.
AB - 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 β-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 β-catenin is necessary for vegetal plate specification and is also sufficient for endoderm formation. In addition, we show that β-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.
UR - http://www.scopus.com/inward/record.url?scp=0032483023&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0032483023&partnerID=8YFLogxK
U2 - 10.1073/pnas.95.16.9343
DO - 10.1073/pnas.95.16.9343
M3 - Article
C2 - 9689082
AN - SCOPUS:0032483023
SN - 0027-8424
VL - 95
SP - 9343
EP - 9348
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 16
ER -