Sarah Carratt and Carmen Castaneda Department of Biology Loyola Marymount University BIOL 398/MATH 388 March 24, 2011 Cold Adaption in Budding Yeast Babette Schade, Gregor Jansen, Malcolm Whiteway, Karl D. Entian, and David Y. Thomas (2004) Molecular Biology of the Cell, Vol. 15,

Stress Affects Transcriptional Response QUESTION: How do cold temperatures and other stress stimuli affect transcriptional response in S. cerevisiae? This study looks at mechanisms responsible for growth and survival at low temperatures FIGURES 1 & 2: Identify the programmed responses to stress at 10°C Contrast early and late cold response for functional categories Compare cold shock as defined by Schade et al. (10°C) to Gasch (25°C)

Cells Respond to Stress Unicellular organisms are affected by a variety of extreme changes in their environments Developed programmed responses to stress into the genetic code, not random The transcription of genes is changed ~10% of the genome responds Genes involved are defined as ESR Little known about mechanisms responsible for growth and survival at low temperatures Cold causes different changes in the physical and biochemical properties Ability to adapt is determined by different regulatory mechanisms

Important Definitions for Figures Division of time Early cold response (ECR) = up to 2 hours Late cold response (LCR) = hours Regulation and color codes GREEN = down-regulated: repressed RED = up-regulated: induced

Hierarchical cluster analysis shows Along the horizontal we have genes clustered. On the vertical axis the individual chips are clustered. Longer time meant that more genes were active. LCR genes are more active.

Distribution of Functional Categories and Regulation Response in ECR & LCR

Transcription: Increased LCR Down-Regulated Genes 1 1 mRNA is synthesized from DNA 833 genes for transcription down-regulated: cell is attempting to conserve energy up-regulated: innate attempt to maintain homeostasis

Protein Synthesis: Large Increase in LCR Down-Regulated Genes 2 2 proteins synthesized from mRNA 380 genes for protein synthesis down-regulated: cell does NOT inefficient energy use up-regulated: stays low, indicates no deficiencies

Stress Response: Increased LCR Up-Regulated Genes (Reversal) 3 3 respond to environment (cold), emergencies, ect. 294 genes for stress response ECR: more down-regulated than up-regulated LCR: more up-regulated genes than down-regulated significance related to function

Gasch vs Schade: Defining Cold Shock in ECR Gasch: 37 to 25 Schade: 30 to 10 key differences in regulation of lower region indicates that there may be different genes a/b: genes that changed at 25 (Gasch)

References In this presentation, images and data were used from the following source: Schade et. al. “Cold Adaption in Budding Yeast” (2004) Molecular Biology of the Cell, Vol. 15,

Acknowledgements We would like to thank the following people for their help with this presentation: Dr. Kam D. Dahlquist, Ph.D. Dr. Ben G. Fitzpatrick, Ph.D.