CELL-DIVISION CONTROL IN ESCHERICHIA-COLI - SPECIFIC INDUCTION OF THE SOS FUNCTION SFIA PROTEIN IS SUFFICIENT TO BLOCK SEPTATION
CELL-DIVISION CONTROL IN ESCHERICHIA-COLI - SPECIFIC INDUCTION OF THE SOS FUNCTION SFIA PROTEIN IS SUFFICIENT TO BLOCK SEPTATION
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DOI：
10.1073/pnas.81.14.4490
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发表时间：
1984-01-01
期刊：
影响因子：
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通讯作者：
GOTTESMAN, S
中科院分区：
文献类型：
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作者：
HUISMAN, O;DARI, R;GOTTESMAN, S
Blocks in DNA replication cause a rapid arrest of cell division in E. coli. The function SfiA (SulA), induced under these conditions as part of the SOS response, is involved in this inhibition of division. To separate the effects of SfiA from those of other SOS functions, a plac-sfiA operon fusion was constructed that permits specific induction of SfiA protein by addition of the lac operon inducer isopropyl .beta.-D-thiogalactopyranoside (IPTG). In lon mutants, in which the unstable SfiA protein has a longer half-life, IPTG caused a rapid arrest of cell division. Under these conditions, there was no concomitant induction of the SOS response. IPTG caused a rapid arrest of cell division in lon+ strains. Thus, induction of the SfiA protein is sufficient to cause inhibition of division. Mutations in the sfiB gene suppresed IPTG-induced SfiA-mediated inhibition of division. At higher SfiA concentrations, however, even sfiB mutants ceased division; an additional mutation genetically inseparable from sfiB restored normal division. These observations reinforce the hypothesis that the SfiB protein, probably required for cell septation, is the target of action of the SfiA division inhibitor.
