Changes in the distribution of cell adhesion molecules β-catenin during temperature shock and cytochalasin B treatment in the sea anemone, Aiptasia pulchella

PAULASKIS, G. M.; SAWYER, S. J*; Southern Illinois University: Changes in the distribution of cell adhesion molecules β-catenin during temperature shock and cytochalasin B treatment in the sea anemone, Aiptasia pulchella

Temperature-induced coral bleaching is increasingly common in coral reefs throughout the world�s oceans. One potential mechanism underlying temperature-induced coral bleaching is loss of the host cell containing the endosymbiotic algae. We have been investigating how cell adhesion is controlled in the tropical sea anemone, Aiptasia pulchella. We have identified an antibody that recognizes the cell-substrate adhesion molecule β-integrin and an antibody that recognizes β-catenin, a molecule that links the cell-cell adhesion molecule cadherin to the actin cytoskeleton. Using immunohistochemistry, we have investigated the tissue localization of these two proteins. Both integrin and β-catenin staining is strong throughout the ectoderm and endoderm and is the strongest between cells. Integrin staining is stronger where cells attach to the mesoglea whereas β-catenin staining is equally distributed throughout the tissue at cell boundaries. To investigate how temperature affects the tissue distribution of these two proteins, anemones were heat shocked for 24 hours at 30°C and then processed for immunohistochemistry. Additionally, we treated anemones with 1 μm cytochalasin B to disrupt the actin cytoskeleton as a positive control. Since both integrins and cadherins interact with the actin cytoskeleton, disruption of the cytoskeleton affects the distribution of these cell adhesion molecules. Cytochalasin treated anemones have a marked change in both integrin and β-catenin staining, while the changes in distribution of these proteins in the heat shocked anemones is more subtle. Further investigations are ongoing to better understand the distribution of both integrins and β-catenin in the tissues of this sea anemone before and after heat shock.

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