| Summary: | <p>The anterior neuroectoderm (ANE) is progressively restricted along the anterior-posterior axis to a territory around the anterior pole during the blastula stages in sea urchin embryos. Information obtained from Wnt/beta-catenin, Wnt/JNK and Wnt/PKC signaling pathways is responsible for this positioning process. Several secreted Wnt modulators of the Dickkopf and Secreted Frizzled Related Protein families (Dkk1, Dkk3, and sFRP1/5) are expressed within the ANE and play important roles in the Wnt signaling network during this process. In this study, we have characterized the function of another secreted Wnt modulator, sFRP3/4, within this Wnt signaling network. Here we have shown that the maternal sFRP3/4 is necessary for the early ANE restriction mechanism during cleavage stage. We also found that Fzl1/2/7 activates zygotic sFRP3/4 during blastula stage, which possibly antagonizes ANE restriction mechanism. During the final phase of ANE restriction mechanism sFRP3/4 and Dkk1 likely works together define the final ANE territory. </p>
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