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Evidence that metabolism and chromosome copy number control mutually exclusive cell fates in Bacillus subtilis
Author(s) -
Chai Yunrong,
Norman Thomas,
Kolter Roberto,
Losick Richard
Publication year - 2011
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/emboj.2011.36
Subject(s) - biology , bacillus subtilis , genetics , chromosome , chromosome segregation , chromosome number , microbiology and biotechnology , bacteria , gene , karyotype
Bacillus subtilis chooses between matrix production and spore formation, which are both controlled by the regulator Spo0A∼P. We report that metabolism and chromosome copy number dictate which fate is adopted. Conditions that favour low Spo0A∼P levels promote matrix production, whereas conditions favouring high levels trigger sporulation. Spo0A∼P directs the synthesis of SinI, an antirepressor for the SinR repressor of matrix genes. The regulatory region of sinI contains an activator site that Spo0A∼P binds strongly and operators that bind Spo0A∼P weakly. Evidence shows that low Spo0A∼P levels turn sinI ON and high levels turn sinI OFF and instead switch sporulation ON. Cells in which sinI and sinR were transplanted from their normal position near the chromosome replication terminus to positions near the origin and cells that harboured an extra copy of the genes were blocked in matrix production. Thus, matrix gene expression is sensitive to the number of copies of sinI and sinR . Because cells at the start of sporulation have two chromosomes and matrix‐producing cells one, chromosome copy number could contribute to cell‐fate determination.