TIN TIN HOLDING SEA URCHINS AT MBL, WOODS HOLE
Tin Tin received a Laura and Arthur Colwin Endowed Summer Research Fellowship to spend part of 2008 summer at the Marine Biological Laboratory in Woods Hole, MA. This experience was written up for the Departmental Newsletter. Read it here. The results are now in press in PLoS ONE. The abstract follows.
The effect of a DNA damaging agent on embryonic cell cycles of the cnidarian Hydractinia echinata
The onset of gastrulation at the Mid-Blastula Transition can accompany profound changes in embryonic cell cycles including the introduction of gap phases and the transition from maternal to zygotic control. Studies in Xenopus and Drosophila embryos have also found that cell cycles respond to DNA damage differently before and after MBT (or its equivalent, MZT, in Drosophila). DNA checkpoints are absent in Xenopus cleavage cycles but are acquired during MBT. Drosophila cleavage nuclei enter an abortive mitosis in the presence of DNA damage whereas post-MZT cells delay the entry into mitosis. Despite attributes that render them workhorses of embryonic cell cycle studies, Xenopus and Drosophila are hardly representative of diverse animal forms that exist. To investigate developmental changes in DNA damage responses in a distant phylum, I studied the effect of an alkylating agent, Methyl Methanesulfonate (MMS), on embryos of Hydractinia echinata. Hydractinia embryos are found to differ from Xenopus embryos in the ability to respond to a DNA damaging agent in early cleavage but are similar to Xenopus and Drosophila embryos in acquiring stronger DNA damage responses and greater resistance to killing by MMS after the onset of gastrulation. This represents the first study of DNA damage responses in the phylum Cnidaria.
She is seeking funding to continue her study of cell cycle and DNA damage responses in marine invertebrates.