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2007 Scientific Report

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VARI |

VARI | 2007 Gene activation during cold acclimation in plants Although plants and their cells obviously have very different forms and functions than animals and their cells, the mechanisms used for expressing genetic information are quite similar. About ten years ago, we applied our emerging interest in chromatin-modifying coactivators to an interesting question in plant biology. Some plants, including the prominent experimental organism Arabidopsis, can sense low (but nonfreezing) temperature in a way that provides protection from subsequent freezing temperatures (Fig. 2). This process is known as cold acclimation. Michael Thomashow, an MSU plant scientist, has explored the genes expressed during this process, and we collaborated with his laboratory to explore the mechanisms involved. We have characterized one particular histone acetyltransferase, termed GCN5, and two of its accessory proteins, ADA2a and ADA2b. Mutations in the genes encoding these coactivator proteins result in diminished expression of cold-regulated genes. Moreover, histones located at these cold-regulated genes become more highly acetylated during initial stages of cold acclimation. We are now working to determine whether GCN5 and the ADA2 proteins are partially or fully responsible for this cold-induced acetylation. We are also collaborating with groups in Greece and Pennsylvania to explore the distinct biological activities of the two ADA2 proteins. This work may help us understand whether the mechanisms by which plants express their genes can be effectively modulated so as to protect crop plants from loss in yield or viability due to environmental stresses such as low temperature. Figure 2. Non-acclimated Acclimated Figure 2. Acclimation of Arabidopsis seedlings. Arabidopsis seedlings were grown on agar plates for three weeks at 20 °C. The plants in the right panel were chilled at 4 °C for two days. All plants were then subjected to subfreezing temperatures (–5 °C) for one day and then were returned to warm temperatures to recover. The acclimated plants remain healthy and green; the nonacclimated plants lose much of their color and die. Photo by K. Pavangadkar. 65 External Collaborators From left: Triezenberg, Roemer, Kutluay Kanchan Pavangadkar and Michael F. Thomashow, Michigan State University, East Lansing Amy S. Hark, Muhlenberg College, Allentown, Pennsylvania Kostas Vlachonasios, Aristotle University of Thessaloniki, Greece

Van Andel Research Institute | Scientific Report George F. Vande Woude, Ph.D. Laboratory of Molecular Oncology 66 Dr. Vande Woude received his M.S. (1962) and Ph.D. (1964) from Rutgers University. From 1964–1972, he served first as a postdoctoral research associate, then as a research virologist for the U.S. Department of Agriculture at Plum Island Animal Disease Center. In 1972, he joined the National Cancer Institute as Head of the Human Tumor Studies and Virus Tumor Biochemistry sections and, in 1980, was appointed Chief of the Laboratory of Molecular Oncology. In 1983, he became Director of the Advanced Bioscience Laboratories–Basic Research Program at the National Cancer Institute’s Frederick Cancer Research and Development Center, a position he held until 1998. From 1995, Dr. Vande Woude first served as Special Advisor to the Director, and then as Director for the Division of Basic Sciences at the National Cancer Institute. In 1999, he was recruited to become the first Director of the Van Andel Research Institute. Staff Laboratory Staff Student Guest Researchers Yu-Wen Zhang, M.D., Ph.D. Chongfeng Gao, Ph.D. Carrie Graveel, Ph.D. Qian Xie, Ph.D. Dafna Kaufman, M.Sc. Matt VanBrocklin, M.S. Jack DeGroot, B.S. Betsy Haak, B.S. Liang Kang, B.S. Rachel Kuznar, B.S. Benjamin Staal, B.S. Ryan Thompson, B.S. Yanli Su, A.M.A.T. Angelique Berens David Wenkert, M.D. Yuehai Shen, Ph.D. Edwin Chen, B.S.

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