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.