strategy of transcription regulation in the budding yeast出芽酵母转录调控的策略.pdf
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Strategy of Transcription Regulation in the Budding
Yeast
1 1,2 1 1 1 1
Sagi Levy , Jan Ihmels , Miri Carmi , Adina Weinberger , Gilgi Friedlander , Naama Barkai *
1 Department of Molecular Genetics and Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot, Israel, 2 Howard
Hughes Medical Institute, Department of Cellular and Molecular Pharmacology, University of California, San Francisco, California, United States of
America
Cells must adjust their gene expression in order to compete in a constantly changing environment. Two alternative strategies
could in principle ensure optimal coordination of gene expression with physiological requirements. First, characters of the
internal physiological state, such as growth rate, metabolite levels, or energy availability, could be feedback to tune gene
expression. Second, internal needs could be inferred from the external environment, using evolutionary-tuned signaling
pathways. Coordination of ribosomal biogenesis with the requirement for protein synthesis is of particular importance, since
cells devote a large fraction of their biosynthetic capacity for ribosomal biogenesis. To define the relative contribution of
internal vs. external sensing to the regulation of ribosomal biogenesis gene expression in yeast, we subjected S. cerevisiae cells
to conditions which decoupled the actual vs. environmentally-expected growth rate. Gene expression followed the
environmental signal according to the expected, but not the actual, growth rate. Simultaneous monitoring of gene expression
and growth rate in continuous cultures further confirmed that ribosome biogenesis genes responded rapidly to changes in the
environments but were oblivious to longer-term change
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