Abstract
In prokaryotes, the toxin-antitoxin systems are thought to play important roles in growth regulation under stress conditions. In the E. coli MazE-MazF system, MazF toxin functions as an mRNA interferase cleaving mRNAs at ACA sequences to inhibit protein synthesis leading to cell growth arrest. Myxococcus xanthus is a bacterium displaying multicellular fruiting body development during which approximately 80% of cells undergo obligatory cell lysis. Here, we demonstrate that M. xanthus has a solitary mazF gene that lacks a cotranscribed antitoxin gene. The mazF deletion results in elimination of the obligatory cell death during development causing dramatic reduction in spore formation. Surprisingly, MrpC, a key developmental regulator, functions as a MazF antitoxin and a mazF transcription activator. Transcription of mrpC and mazF is negatively regulated via MrpC phosphorylation by a Ser/Thr kinase cascade. These findings reveal the regulated deployment of a toxin gene for developmental programmed cell death in bacteria.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Apoptosis / genetics*
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Apoptosis Regulatory Proteins / genetics
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Apoptosis Regulatory Proteins / metabolism*
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Bacterial Proteins / genetics
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Bacterial Proteins / metabolism*
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Base Sequence
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / metabolism
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Cell Division / physiology
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Cell Proliferation
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DNA-Binding Proteins / genetics*
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DNA-Binding Proteins / metabolism
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Endoribonucleases / genetics
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Endoribonucleases / metabolism*
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Escherichia coli Proteins / genetics*
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Escherichia coli Proteins / metabolism
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Gene Deletion
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Gene Expression Regulation, Bacterial / genetics
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Molecular Sequence Data
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Myxococcus / enzymology*
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Myxococcus / genetics
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Phosphorylation
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RNA, Messenger / genetics
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RNA, Messenger / metabolism
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Sequence Homology, Amino Acid
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Spheroids, Cellular / cytology
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Spheroids, Cellular / metabolism
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Transcription Factors / genetics
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Transcription Factors / metabolism
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Transcription, Genetic / genetics
Substances
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Apoptosis Regulatory Proteins
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Bacterial Proteins
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Cell Cycle Proteins
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DNA-Binding Proteins
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Escherichia coli Proteins
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MazF protein, E coli
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MrpC protein, Myxococcus xanthus
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RNA, Messenger
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Transcription Factors
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Endoribonucleases