A novel microdissection model for probing cellular interactions. III. mapping with Con A and mannan beads

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Adhesion between the archenteron tip and blastocoel roof in the NIH designated sea urchin embryo model is a cellular interaction that has interested investigators for over a century, but its molecular basis is not understood. Here we microdissect the two components of this cellular interaction and use concanavalin A (Con A) and mannan derivatized agarose beads to map molecular groups that may be involved in mediating the cellular interaction. In over 50 separate trials, the results were either 100% binding or no binding, and indicated that Con A derivatized and mannan derivatized agarose beads bound to formaldehyde fixed dissected archenterons and roofs in both sterile distilled water (ddH2O) and pH 8.0 artificial sea water (ASW), 15°C, while 0.2 M alpha methyl mannose blocked the binding. Previous work indicated that fixed tissue displayed the same cell surface properties as live tissue. The results suggest that both Con A binding ligands and mannan binding partners are present on the two components of the cellular interaction. These studies offer a novel approach to map glycans and glycan binding partners that may be functionally important. By microdissecting the components of cellular interactions out of the embryo proper, these components can be probed in pristine media away from factors in intact embryos that could confuse results (Supported by NIH NIGMS SCORE S0648680, MARC, RISE, the Joseph Drown Foundation, the Sidney Stern Memorial Trust, and CSU Northridge Biology Full Immersion Research Experience (FIRE) course funding).