Mechanisms Regulating Suspended Animation in Caenorhabditis elegans
Pamela A. Padilla, University of North Texas
In nature, complex biological processes, such as development or organ function, arrest in response to environmental changes. Examples of states in which biological processes arrest include hibernation, torpor and diapause. In the laboratory, we used decreased oxygen tension (anoxia) to induce a reversible arrest, termed suspended animation, in animal systems. Anoxia induces a state of suspended animation in which development, cell division and various behaviors reversibly arrest in the nematode Caenorhabditis elegans and fish (zebrafish and killifish) (1-3). C. elegans are able to survive in a state of suspended animation for 1 to 5 days, depending on developmental stage. Using genetic and cellular analysis, to study embryos in a state of suspended animation we determined that cells arrest at specific positions of the cell cycle and this arrest requires known and potentially new cell cycle checkpoint pathways (4, 5). Analysis of adult animals in a state of suspended animation revealed genetic pathways and physiological states that increases the duration of suspended animation (6). For example, alterations of the insulin-like signaling pathway or decreasing oocyte fertilization increases viability of animals in a state of suspended animation. These studies will increase our understanding of how cellular processes are affected by environmental changes; this is relevant to understanding many human health related diseases. Whether the mechanisms involved with suspended animation overlap with other arrested states such as diapause remains to be determined.
1. P. A. Padilla, T. G. Nystul, R. A. Zager, A. C. Johnson, M. B. Roth, Mol Biol Cell 13, 1473 (2002).
2. P. A. Padilla, M. B. Roth, Proc Natl Acad Sci U S A 12, 12 (2001).
3. J. E. Podrabsky, J. P. Lopez, T. W. Fan, R. Higashi, G. N. Somero, J Exp Biol 210, 2253 (Jul, 2007).
4. T. G. Nystul, J. P. Goldmark, P. A. Padilla, M. B. Roth, Science 302, 1038 (Nov 7, 2003).
5. V. A. Hajeri, A. M. Stewart, L. L. Moore, P. A. Padilla, Cell Div 3, 6 (2008).
6. A. R. Mendenhall, B. Larue, P. A. Padilla, Genetics (Sep 15, 2006).