Visualizing egg and embryonic polarity

Lauren T. Smith, Athula Wikramanayake

Research output: Chapter in Book/Report/Conference proceedingChapter

Abstract

During development metazoan embryos have to establish the molecular coordinates for elaboration of the embryonic body plan. Typically, bilaterian (bilaterally symmetric animals) embryos establish anterior-posterior (AP) and dorsal-ventral (DV) axes, and in most cases the AP axis is established first. For over a century it has been known that formation of the AP axis is strongly influenced by the primary axis of the egg, the animal-vegetal (AV) axis. The molecular basis for how the AV axis influences AP polarity remains poorly understood, but sea urchins have proven to be important for elucidating the molecular basis for this process. In fact, it is the first model system where a critical role for Wnt signaling in specification and patterning the AV and AP axis was first established. One current area of research is focused on identifying the maternal factors that regulate localized activation of Wnt/β-catenin signaling at the vegetal pole during development. An essential tool for this work is the means to identify the AV polarity in oocytes and eggs. This permits investigation into how polarity is established and allows development of experimental strategies to identify maternal factors that contribute to and control axial polarity. This chapter provides protocols to accomplish this in sea urchin eggs and early embryos. We describe simple methods to visualize polarity including direct observation of eggs and oocytes, using a microscope for overt morphological signs of polarity, and more extensive methods involving localization of known factors indicative of inherent embryonic polarity, such as the upstream regulators of the Wnt/β-catenin pathway.

Original languageEnglish (US)
Title of host publicationMethods in Cell Biology
PublisherAcademic Press Inc.
Pages251-268
Number of pages18
DOIs
StatePublished - Jan 1 2019

Publication series

NameMethods in Cell Biology
Volume150
ISSN (Print)0091-679X

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Keywords

  • Animal-vegetal axis
  • Anterior-posterior axis
  • Oocyte and egg polarity
  • Wnt signaling

ASJC Scopus subject areas

  • Cell Biology

Cite this

Smith, L. T., & Wikramanayake, A. (2019). Visualizing egg and embryonic polarity. In Methods in Cell Biology (pp. 251-268). (Methods in Cell Biology; Vol. 150). Academic Press Inc.. https://doi.org/10.1016/bs.mcb.2019.01.001