Screening of genes that respond to cryopreservation stress using yeast DNA microarray q Mine Odani, Yasuhiko Komatsu, Syuichi Oka, and Hitoshi Iwahashi * International Patent Organism Depositary, National Institute of Advanced Industrial Science and Technology, Ibaraki 305-8566, Japan Received 27 January 2003; accepted 3 September 2003 Abstract We studied the response of yeast cells after cryopreservation treatment using DNA microarray technology. Genes that contribute to ‘‘Cell rescue, defense and virulence,’’ ‘‘energy,’’ and ‘‘metabolism,’’ were significantly induced. These genes were classified as encoding heat shock proteins, oxidative stress scavenger, and enzymes involved in glucose metabolism. The expression profile of mRNA after cryopreservation treatment was calculated to be closer to that following treatment with detergent or plant oils rather than by other stress factors such as heavy metals and agricultural chemicals. These results suggest that the cryopreservation treatment caused damage to the structure of the cell wall and cellular organelles. This was supported by the localization of the products of the induced genes at the cell wall and within cellular organelles. Ó 2003 Elsevier Inc. All rights reserved. Keywords: DNA microarray; Cryopreservation; Freeze–thaw; Saccharomyces cerevisiae Cryopreservation is widely accepted as a suit- able method for long term storage of a variety of living cells and is applied to many industrial, medical, agricultural, and food technologies. However, the cryopreservation procedure involves freezing and thawing treatments. These treatments cause damage to living cells, and this often leads to cell death. In the depository institute, many kinds of organisms are deposited but the organisms are not always maintained by cryopreservation or dried preservation. Some organisms, such as algae, fungi, and plant cells, easily lose viability and must be maintained through subcultivation. However, cultivation is expensive and can result in a loss of original characteristics. Thus, we have been studying the application of cryopreservation for these organisms. It has been proposed that injury caused by freezing and thawing is the result of several factors such as ice nucleation and dehydration [11]. Damage to membrane structures by freezing and thawing has been observed by electron mi- croscopy [7]. Cells can also suffer biochemical damage such as oxidative stress by reactive oxygen species formed during the thawing process [4,15]. q This work was funded by institutional sources. * Corresponding author. Fax: +81-298-61-6078. E-mail address: hitoshi.iwahashi@aist.go.jp (H. Iwahashi). 0011-2240/$ - see front matter Ó 2003 Elsevier Inc. All rights reserved. doi:10.1016/j.cryobiol.2003.09.001 Cryobiology 47 (2003) 155–164 www.elsevier.com/locate/ycryo