RUI: Molecular effects of ultraviolet radiation on the cell cycle and development of sea urchins
Nikki L. Adams, Cal Poly State University
Many marine invertebrates are exposed to damaging levels of naturally occurring ultraviolet radiation (UVR, 290-400 nm), which can lead to detrimental effects at the ecological, organismal, cellular and molecular levels. Furthermore, there is increasing evidence that broadcast spawned gametes, embryos, and larvae of marine invertebrates are the most sensitive life stages to UVR. One of the best model organisms for studying effects of UVR at the molecular and organismal levels is the sea urchin egg and embryo. UV-irradiation of sea urchin eggs and embryos delays cell division and can cause later developmental delays and gross abnormalities that lead to death or malformation of larvae. Such delays and defects in development may increase the risk of further damage and may eventually affect population dynamics. Fortunately, some sea urchin eggs and embryos contain natural sunscreening compounds, mycosporine-like amino acids (MAAs), which protect them from some UV-induced damage. However, the molecular targets of UVR have not been identified and the mechanism of protection by MAAs remains elusive. The proposed research will identify molecules that are affected by UV-irradiation and that affect progression through mitosis in sea urchins eggs and embryos using controlled laboratory and field experimental approaches. More specifically: effects of UVR on the activity of the cell cycle regulatory proteins (cyclins, cyclin dependent kinases, and proteins that regulate their activity) and DNA will be identified in embryos of the sea urchin (Strongylocentrotus purpuratus), Ultimately, targets will be tested to determine whether they are protected from UVR by MAAs. These studies integrate ecology, physiology, developmental biology and cell and molecular biology and have implications for all organisms that undergo cell division and are exposed to sunlight. The proposed experiments strive to provide a foundation to answer long- standing questions about the molecular mechanisms controlling stress-induced abnormalities in development of marine invertebrates. In addition, undergraduate and graduate students will participate significantly in this work as intellectual partners, whereby they design their own experiments, test hypotheses and learn how to present their results orally and in scientific manuscripts, so they are better prepared for careers in science.
