Abstract submitted to the Pennsylvania Academy of Science for inclusion in the April 12-14 1996 meeting held at State College, PA.

Retinoic acid affects vegetal plate formation in sea urchin embryos.

Katrina M. Robbins, Denise M. Evans, David S. Richard, and Margaret T. Peeler. Biology Department, Susquehanna University, Selinsgrove, PA 17870.


Retinoic acid is a known morphogen and teratogen in vertebrates, where it affects anterior-posterior axis formation. We have investigated the effects of exposure to exogenous retinoic acid on sea urchin embryonic development. Specifically, all trans-retinoic acid disrupted the morphology of embryos so that the animal pole exhibited a thickening similar to that normally seen at the vegetal plate. We have quantified this effect and have found it to be dose dependent. In control embryos, the thickness of the blastula wall at the animal pole was approximately half that of the vegetal plate, whereas in embryos grown in 1.66(10-5M) retinoic acid, the thickness of the blastula wall was equal at the animal and vegetal poles. Intermediate concentrations resulted in intermediate ratios. Studies characterizing the binding of tritiated all trans-retinoic acid to cytosolic factors in sea urchin embryo homogenates are being conducted, and preliminary data indicate that some binding activity may exist. These results suggest a morphogenetic role for retinoic acid during embryonic development in the sea urchin.