Monster Seminar JAM - A Case Study for using microarray technology to profile environmentally induced changes in gene expression in fish: Searching for the molecular basis of eurythermality in the annual killifish Austrofundulus limnaeus
Dr. Jason Podrabsky, Dept. of Biology, Portland State University.
The annual killifish Austrofundulus limnaeus lives in small ephemeral ponds in tropical savanna regions of northern South America. These fish inhabit ponds that are very small and thus experience large-scale fluctuations in many physical parameters on a daily basis. Field measurements indicate that these ponds regularly experience 15-25¿C fluctuations in temperature on a daily basis. To investigate the effects of large-scale temperature fluctuations on the gene expression of these fish we produced and used an A. limnaeus liver-specific cDNA microarray to profile changes in gene expression during laboratory acclimation to constant and fluctuating temperature regimes. We discovered that about 10% (over 300 spots) of our 5000 spot microarray represented genes that changed their expression pattern significantly in response to temperature acclimation. These genes belong to diverse functional groups that affect almost every aspect of cell biology and physiology. For instance, transcripts for many molecular chaperones, and proteins that control and regulate cell growth and proliferation were highly responsive to changes in temperature, as were genes involved in cholesterol and membrane biosynthesis and restructuring. This project has led to the development of many novel hypotheses concerning how organisms deal with a variable thermal environment. The most interesting of these hypotheses is the identification of a putative global regulator of transcription in response to temperature that has until now not even been implicated in temperature acclimation.
Date and Time:
December 4, 2003,
11:00 am - 12:30 pm