Hand 97-23746 Dormancy in animals provides an important means to survive harsh environmental conditions. This work will investigate how certain cells are able to survive long periods of dormancy that are induced by the removal of oxygen (anoxia). Under anoxia, energy metabolism and development are shut down. There are three specific research objectives for this project. First, the rate of transcription (synthesis of messenger RNA from DNA) will be measured in nuclei and mitochondria isolated from active animals and dormant animals. The PI's prediction is that transcription will be depressed under anoxia, which would be consistent with the fact that development ceases under anoxia in our experimental animal (a shrimp embryo). Second, the stability of messenger RNA (mRNA) under anoxia will measured. The PI's hypothesis is that degradation of mRNA (a normal process in active cells) will be is depressed during dormancy. Conservation of mRNA molecules during dormancy might favor a quick resumption of protein synthesis as soon as oxygen is returned. Third, the PI will hypothesize that there is an oxygen sensor in the mitochondria of these animals that can control the rate of protein synthesis when oxygen availability is reduced. Experiments will be performed to test whether or not the sensor is a home protein (i.e., similar to oxygen binding proteins like hemoglobin). The mechanisms by which cells withstand long bouts of dormancy are apt to have important implications for numerous cases where metabolism is unavoidably disrupted -organ and tissue transplantation, acute blockage of blood flow to tissues, and oxygen deprivation. From an ecological perspective, the work should help explain how environmental stimuli that promote entry into dormancy are linked to the required survival responses. ,,. 1
