Nitrogen-starvation induced chlorosis in cyanobacteria: A proteolytic program for maintenance of viability

点击翻译按钮获取中文摘要

When non-diazotrophic cyanobacteria are deprived of combined nitrogen sources, cells degrade their photosynthetic pigments in a process termed chlorosis. Previously, we have shown that bleaching of the cells is part of a simple developmental program which is characterized by the sequential decay of metabolic activitiy and the stepwise degradation of almost all cellular proteins to near completion by so far unidentified proteolytic activities. It results in cells that are able to survive for undefined long periods under non-growing conditions in a dormant state. In this project we want to analyze the proteolytic process underlying chlorosis. Initially, we will focus on the identification of proteases and related factors which carry out chlorosis. In a next step regulation of proteolysis will be studied: which signals initiate the proteolytic process, how are the proteins sequentially targeted to proteolysis, how are the proteases controlled to prevent a complete degradation of essential activities? We employ the model organism Synechocystis PCC 6803, for which the genome data are available and for which molecular biology methods are established. Experimental approaches include proteome and transcriptome analyses, molecular genetics, biochemical and physiological analyses. The broad experimental approach requires intensive collaboration within the priority program.