title: Subcellular localization of the Bacillus subtilis structural maintenance of chromosomes (SMC) protein.
abstract: The Bacillus subtilis structural maintenance of chromosomes (SMC) protein is a member of a large family of proteins involved in chromosome organization. We found that SMC is a moderately abundant protein ( approximately 1000 dimers per cell). In vivo cross-linking and immunoprecipitation assays revealed that SMC binds to many regions on the chromosome. Visualization of SMC in live cells using a fusion to the green fluorescent protein (GFP) and in fixed cells using immunofluorescence microscopy indicated that a portion of SMC localizes as discrete foci in positions similar to that of the DNA replication machinery (replisome). When visualized simultaneously, SMC and the replisome were often in similar regions of the cell but did not always co-localize. Persistence of SMC foci did not depend on ongoing replication, but did depend on ScpA and ScpB, two proteins thought to interact with SMC. Our results indicate that SMC is bound to many sites on the chromosome and a concentration of SMC is localized near replication forks, perhaps there to bind and organize newly replicated DNA.
authors.affiliation: Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Janet C
authors.initials: JC
authors.lastname: Lindow
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Kuwano
authors.forename: Shigeki
authors.initials: S
authors.lastname: Moriya
authors.forename: Alan D
authors.initials: AD
authors.lastname: Grossman
mesh_terms: D018829:Adhesins, Bacterial; D001412:Bacillus subtilis / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D022003:Cell Nucleus Structures / Q000378:metabolism; D002843:Chromatin / Q000276:immunology; D002876:Chromosomes, Bacterial / Q000378:metabolism*; D004261:DNA Replication; D019281:Dimerization; D010450:Endopeptidases / Q000378:metabolism; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D011233:Precipitin Tests; D011994:Recombinant Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism
chemical_list: D018829:Adhesins, Bacterial; D001426:Bacterial Proteins; D018797:Cell Cycle Proteins; D002843:Chromatin; D008164:Luminescent Proteins; D011994:Recombinant Proteins; C118650:SMC protein, Bacteria; D049452:Green Fluorescent Proteins; D010450:Endopeptidases; C053088:C5a peptidase