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IDENTIFICATION OF PROMOTER SEQUENCES INVOLVED IN THE RESPONSE TO ROTATING WALL VESSEL GROWTH IN SACCHAROMYCES CEREVISIAE. Kelly Johanson¹, Patricia L Allen², Luis A Cubano², R. Bryan Klassen³, Fawn Lewis¹, Ratan M Joshi⁴, Terry Stoming⁴, Linda Hyman¹ and Timothy G Hammond^{2  1}Departments of Biochemistry, Surgery, & Medicine, ²Tulane/VA Environmental Astrobiology Center, ³Tulane/Xavier Center for BioEnvironmental Research, New Orleans, LA 70112 and ⁴Molecular Biology Core Facility Institute of Molecular Medicine and Genetics Department of Biochemistry and Molecular Biology Medical College of Georgia, Augusta, GA 30912.

     Although engineering optimization of suspension culture was undertaken to model culture conditions in space flight, it has found its greatest utility in commercial ground-based applications.  The suspension culture system optimized to provide minimal shear with laminar flow is the rotating wall vessel (RWV), a horizontally rotating cylinder with a co-axial oxygenator.  We use genome-wide DNA microarrays and samples of mRNA from Saccharomyces cerevisiae cultures to determine gene expression changes that occur during RWV culture.  Using periodicity and correlation algorithms (Gibbs alignment procedure) we assay clusters of rotating wall vessel responsive genes for known and new promoter elements to define the mechanisms mediating these genetic changes.  Overall 446 genes were up-regulated at one or more time points in the rotating wall vessel while 282 were down-regulated.  Candidate binding motifs similar to the Rap1 and Buf binding motifs were identified in the promoter regions of genes whose expression levels were influenced by growth in the rotating wall vessel.  Furthermore, the identification of a significant amount of rotating wall vessel responsive genes with no known function may open the possibility of genes with functions related to changes in flow conditions.

     This worked was supported by NASA NRA NAG-8-1362, NASA Cooperative agreement NCC 2-1177 and DOD DTRA to the Tulane/Xavier Center for Bioenvironmental Research. Affymetrix system was purchased by the Georgia Research Alliance.