The Escherichia coli mazEF suicide module mediates thymineless death.
In 1954, Cohen and Barner discovered that a thymine auxotrophic (thyA) mutant of Escherichia coli undergoes cell death in response to thymine starvation. This phenomenon, called thymineless death (TLD), has also been found in many other organisms, including prokaryotes and eukaryotes. Though TLD has been studied intensively, its molecular mechanism has not yet been explained. Previously we reported on the E. coli mazEF system, a regulatable chromosomal suicide module that can be triggered by various stress conditions. MazF is a stable toxin, and MazE is an unstable antitoxin. Here, we show that cell death that is mediated by the mazEF module can also be activated by thymine starvation. We found that TLD depends on E. coli mazEF and that under thymine starvation, the activity of the mazEF promoter P(2) is significantly reduced. Our results, which describe thymine starvation as a trigger for a built-in death program, have implications for programmed cell death in both prokaryotes and eukaryotes.
Sat
Boaz
B
Department of Molecular Biology, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel.
Reches
Myriam
M
Engelberg-Kulka
Hanna
H
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D017209:Apoptosis; D003470:Culture Media; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004722:Endoribonucleases; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics / Q000254:growth & development* / Q000502:physiology; D029968:Escherichia coli Proteins / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D011401:Promoter Regions, Genetic; D013420:Sulfamethoxazole / Q000494:pharmacology; D013941:Thymine / Q000378:metabolism*; D014158:Transcription, Genetic; D014295:Trimethoprim / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D003470:Culture Media; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C422954:MazE protein, E coli; C422955:MazF protein, E coli; D014295:Trimethoprim; D004722:Endoribonucleases; D013420:Sulfamethoxazole; D013941:Thymine