title: SOS induction in a subpopulation of structural maintenance of chromosome (Smc) mutant cells in Bacillus subtilis.
abstract: The structural maintenance of chromosome (Smc) protein is highly conserved and involved in chromosome compaction, cohesion, and other DNA-related processes. In Bacillus subtilis, smc null mutations cause defects in DNA supercoiling, chromosome compaction, and chromosome partitioning. We investigated the effects of smc mutations on global gene expression in B. subtilis using DNA microarrays. We found that an smc null mutation caused partial induction of the SOS response, including induction of the defective prophage PBSX. Analysis of SOS and phage gene expression in single cells indicated that approximately 1% of smc mutants have fully induced SOS and PBSX gene expression while the other 99% of cells appear to have little or no expression. We found that induction of PBSX was not responsible for the chromosome partitioning or compaction defects of smc mutants. Similar inductions of the SOS response and PBSX were observed in cells depleted of topoisomerase I, an enzyme that relaxes negatively supercoiled DNA.
authors.affiliation: Department of Biology, Building 68-530, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Britton
authors.forename: Elke
authors.initials: E
authors.lastname: Küster-Schöck
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Auchtung
authors.forename: Alan D
authors.initials: AD
authors.lastname: Grossman
mesh_terms: D019677:Artificial Gene Fusion; D017103:Bacillus Phages / Q000235:genetics; D001412:Bacillus subtilis / Q000235:genetics*; D001426:Bacterial Proteins / Q000032:analysis / Q000235:genetics*; D018797:Cell Cycle Proteins / Q000235:genetics*; D002876:Chromosomes, Bacterial / Q000378:metabolism; D004264:DNA Topoisomerases, Type I / Q000378:metabolism; D017353:Gene Deletion; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics*; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000032:analysis / Q000235:genetics; D008164:Luminescent Proteins / Q000032:analysis / Q000235:genetics; D008856:Microscopy, Fluorescence; D020411:Oligonucleotide Array Sequence Analysis; D013014:SOS Response, Genetics; D014775:Virus Activation
chemical_list: D001426:Bacterial Proteins; D018797:Cell Cycle Proteins; D008164:Luminescent Proteins; C118650:SMC protein, Bacteria; C054562:yellow fluorescent protein, Bacteria; D049452:Green Fluorescent Proteins; D004264:DNA Topoisomerases, Type I