Changes in the protein complement following UV irradiation and their photoreversal in sea urchin (Hemicentrotus pulcherrimus) embryos

. Ultraviolet (254 nm, 200 J/m2) irradiation of sea urchin (Hemicentrotus pulcherrimus) embryos during the cleavage stage caused inhibition of morphogenesis, that is, pluteus larva formation. Exposure of the embryos to visible light just after UV irradiation caused the complete reversal of the UV effect, that is, UV-irradiated embryos can be reprogrammed for normal development (photorever-sal; PR). We used two-dimensional electrophoresis to determine the patterns of accumulating proteins in normal, UV-irradiated and photoreversed embryos. Many qualitative and quantitative variations in the accumulating proteins in the UV-irradiated embryos were demonstrated. When embryos reached the pluteus larva stage at 48 h after fertilization, the amounts of actin and tubulin were less in the UV-irradiated embryos than in normal embryos. One extracellular protein (mol. wt. 63 k) did not appear in the UV-irradiated embryos. Most of the UV effect on the protein pattern was photoreversed.