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▶ 제 목 : Cytokinin signaling in plants: A bacterial paradigm in a eukaryotic world.
▶ 일 시 : 2007년 5월 30일 (수) 오후1:30
▶ 연 사 : Joseph J. Kieber
▶ 장 소 : 생명과학관 104호
Cytokinins have been implicated a wide variety of plant growth and development processes and have been shown to interact with various other signals. Recent studies have demonstrated that cytokinin signal transduction occurs through a classic bacterial two-component signaling system. Two-component systems are the primary means by which bacteria sense and respond to environmental stimuli. These systems are comprised of a number of distinct elements, namely histidine kinases, response regulators and in the case of phosphorelays, histidine phosphotransfer proteins (HPts). Signal propagation relies on the transfer of phosphates between alternating histidine and aspartic acid residues. Genes encoding proteins corresponding to each of these elements have been identified in Arabidopsis. Using molecular, genetic and biochemical approaches, the role of the Arabidopsis two-component genes in plant growth and development has been defined. There is extensive functional redundancy in these gene families. Analysis of lines harboring multiple disruptions in multiple two-component genes has indicated that theseelements play roles in various signaling pathways, including circadian rhythm, the regulation of meristem function, vascular differentiation, nutrient acquisition and the response to pathogens. These effects can be generally linked to perturbation in cytokinin responsiveness. In related studies, we have defined the response of the transcriptome to cytokinin. One set of cytokinin-regulated genes encode transcription factors, and we have begun to analyze the role of these in the response to cytokinin. We have found a group of AP2-related transcription factors that translocate to the nucleus rapidly in response to cytokinin, and analysis of hypomorphic mutations indicates that these CRFs mediate a subset of the transcriptional response to cytokinin. A model incorporating these and other results will be presented.
※ 문의 : 생명과학과 황인환 교수 (☎ 279-2128 )