Macromolecular Synthesis in Newly Transformed Cells of
            <i>Bacillus subtilis</i>

McCarthy, Charlotte; Nester, Eugene W.

doi:10.1128/jb.94.1.131-140.1967

Cited by 63 publications

(37 citation statements)

References 35 publications

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“…Not only are cell division and elongation arrested, but DNA replication also appears to be blocked, as the nuclear bodies of competent cells retain the appearance of resting nucleoids. It has been reported that DNA replication and stable RNA synthesis are blocked in the presumptive competent cells during the development of competence (Dooley et al, 1971) and in newly transformed cells (McCarthy and Nester, 1967). The present results confirm that the inhibition of DNA replication continues during outgrowth.…”

Section: Discussionsupporting

confidence: 88%

A ComGA‐dependent checkpoint limits growth during the escape from competence

Haijema¹,

Hahn²,

Haynes³

et al. 2001

Molecular Microbiology

116

161

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In Bacillus subtilis, competence for transformation develops in 5-10% of the cells in a stationary phase culture. These cells exhibit a prolonged lag in the resumption of growth and cell division during the escape from competence. To better understand the basis of this lag, we have characterized competent cultures microscopically. To distinguish the minority of competent cells, a translational fusion between ComK, the competence transcription factor, and the green fluorescent protein (GFP) was used as a marker. Only 5-10% of the cells in a competent culture were fluorescent, indicating that ComK synthesis is an all or nothing event. To validate the identification of competent cells, we demonstrated the coincident expression of comEA, a late competence gene, and comK-gfp. Competent cells resemble stationary phase cells; the majority are single (not in chains), contain single nucleoids, and rarely contain FtsZ rings. Upon dilution into fresh medium, competent cells maintain this appearance for about 2 h. In contrast, the majority of non-competent cells rapidly resume growth, exhibiting chaining, nuclear division and FtsZ-ring formation. The late competence protein ComGA is required for the competence-related block in chromosome replication and cell division. In the competent cells of a comGA mutant culture, chromosomal replication and FtsZ-ring formation were no longer blocked, although competent comGA mutant cells were abnormal in appearance. It is likely that one role for ComGA is to prevent growth, chromosome replication and cell division until ComK can be eliminated by degradation. A mutation in the ATP-binding site of comGA inactivated the protein for transformation but did not prevent it from inhibiting DNA replication and cell division. The buoyant density difference between competent and non-competent cells depends on the competence-specific growth arrest.

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Section: Discussionsupporting

confidence: 88%

A ComGA‐dependent checkpoint limits growth during the escape from competence

Haijema¹,

Hahn²,

Haynes³

et al. 2001

Molecular Microbiology

116

161

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“…The most suggestive comparison may be with a recent report that when the initiation of chromosome replication is specifically blocked in E. coli, cells become elongated, with centrally located nucleoids (Bernander et aL, 1995). mecA inactivation may be responsible for the DNA replication arrest of competent cells It has been shown that competent cells of B. subtilis are essentially inactive with respect to DNA replication (Dooley et aL, 1971;Dubnau and Cirigliano, 1973), and that chromosome replication in these cells is arrested at or near the replication terminus (McCarthy and Nester, 1967). Reversal of this block occurs with a delay, resulting in a prolonged lag before competent cells resume growth (McCarthy and Nester, 1967;Nester and Stocker, 1963).…”

Section: Inappropriate Comk Synthesis Causes An Abnormality In Nucleosupporting

confidence: 57%

“…mecA inactivation may be responsible for the DNA replication arrest of competent cells It has been shown that competent cells of B. subtilis are essentially inactive with respect to DNA replication (Dooley et aL, 1971;Dubnau and Cirigliano, 1973), and that chromosome replication in these cells is arrested at or near the replication terminus (McCarthy and Nester, 1967). Reversal of this block occurs with a delay, resulting in a prolonged lag before competent cells resume growth (McCarthy and Nester, 1967;Nester and Stocker, 1963). We have shown that the inactivation of mecA results in the loss of colony-forming ability and in a prolonged lag in the resumption of growth of the entire culture.…”

Section: Inappropriate Comk Synthesis Causes An Abnormality In Nucleomentioning

confidence: 99%

Inactivation of mecA prevents recovery from the competent state and interferes with cell division and the partitioning of nucleoids in Bacillus subtilis

Hahn¹,

Bylund

Haines

et al. 1995

Molecular Microbiology

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The development of genetic competence in Bacillus subtilis requires the synthesis of ComK, a transcription factor, which is normally produced as a culture enters the stationary phase. This synthesis is known to be regulated in part by the protein MecA. Loss-of-function mutations in mecA result in overexpression of ComK and its appearance early during exponential growth. We show here that mecA inactivation also causes a loss of colony-forming ability, especially during stationary phase. This loss is accompanied by the appearance of cells in which normal nucleoid separation has failed to occur. Renografin gradient fractionation of mecA cultures grown to competence reveals that nearly 100% of the cells band at the low buoyant density characteristic of competent cells, and that this low density is competence-related. The loss of viability, the low buoyant density and the nucleoid separation defect, are all comK-dependent. The loss of viability can be reversed by even the transient introduction of mecA+. It is proposed that these effects of ComK overexpression are related to the DNA replication arrest normally exhibited by the competent cell fraction and that MecA is needed to reverse this arrest and to permit escape from the competent state. The shift of nearly 100% of the cells to light buoyant density in a mecA mutant culture strongly suggests that the MecA protein is a regulator of the cell-type-specific expression of competence.

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“…There may be two reasons for this. One is that competent cells are in a state of "biosynthetic latency" (31), in which DNA synthesis is drastically reduced compared with that in noncompetent cells (10,27). Postreplication repair must be considerably delayed in transformants relative to the beginming of excision repair, which should be able to begin as soon as the donor DNA is integrated.…”

Section: Discussionmentioning

confidence: 99%

Postreplication repair of ultraviolet-irradiated transforming deoxyribonucleic acid in Bacillus subtilis

Hadden¹

1981

J Bacteriol

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Repair of ultraviolet-irradiated transforming deoxyribonucleic acid (DNA) in several strains of Bacillus subtilis was studied in order to determine the effects of excision repair and postreplication repair on transformation. Two mutations that cause a Uvr-phenotype (uvr-1 and uvr-42) were shown to have strikingly different effects on repair of ultraviolet-irradiated transforming DNA. Genetic and kinetic evidence is presented to show that integrated DNA was apparently repaired by both excision and postreplication repair in wild-type and in uvr-1 recipients, although the latter excise pyrimidine dimers very slowly. In uvr-42 mutants, which are defective in incision at pyrimidine dimers, dimer-containing DNA was integrated. Postreplication repair apparently saved uvr-42 recipient cells from the lethal effects of integrated dimers, but the recombination events accompanying postreplication repair greatly reduced the linkage between closely linked genetic markers in the donor DNA. Repair of transforming DNA in a recG recipient, which does excision repair but not postreplication repair, was nearly as efficient as in wild-type cells. However, in this recipient linkage was altered only slightly, if at all, compared with wild-type cells. The apparent reduction in size of integrated regions of ultraviolet-irradiated transforming DNA probably results mainly from postreplication repair of larger integrated regions.

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Macromolecular Synthesis in Newly Transformed Cells of Bacillus subtilis

Cited by 63 publications

References 35 publications

A ComGA‐dependent checkpoint limits growth during the escape from competence

A ComGA‐dependent checkpoint limits growth during the escape from competence

Inactivation of mecA prevents recovery from the competent state and interferes with cell division and the partitioning of nucleoids in Bacillus subtilis

Postreplication repair of ultraviolet-irradiated transforming deoxyribonucleic acid in Bacillus subtilis

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