Breakage prior to entry of donor DNA in Pneumococcus transformation

Morrison, Donald A.; Guild, Walter R.

doi:10.1016/0005-2787(73)90226-8

Cited by 72 publications

(68 citation statements)

References 14 publications

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“…DNA transport across the cytoplasmic membrane in natural transformation occurs in a single-stranded fashion in Bacillus (Piechowska & Fox, 1971 ;DavidoffAbelson & Dubnau, 1973), and Streptococcus (Morrison & Guild, 1973) and possibly also in Haemophilus (Kahn et al, 1983). We have shown here that this is also the case in Acinetobacter.…”

Section: Discussionsupporting

confidence: 60%

Physiological characterization of natural transformation in Acinetobacter calcoaceticus

Palmen

Vosman

Buijsman

et al. 1993

Journal of General Microbiology

163

153

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~Acinetobacter calcoaceticus BD413 develops competence for natural transformation immediately after the start of the exponential growth-phase and remains competent up to a few hours into the stationary phase, after which competence gradually declines. The transformation frequencies obtained strongly depend on the kind of transforming DNA and the incubation time with DNA. Up to 25% of the cells in a culture can be transformed. DNA uptake in Acinetobacter does not display sequence specificity, is Mg2+-, Mn2+-or Ca2+dependent and is uncoupler sensitive. The transforming DNA enters the cells in single-stranded form. These properties constitute a unique combination, not previously observed in other bacteria, and make A. calcoaceticus ideally suited for detailed studies of the bioenergetics of DNA translocation.

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Section: Discussionsupporting

confidence: 60%

Physiological characterization of natural transformation in Acinetobacter calcoaceticus

Palmen

Vosman

Buijsman

et al. 1993

Journal of General Microbiology

163

153

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“…There is abundant evidence in other bacterial transformation systems for endonucleolytic degradation of cell-associated donor DNA. For instance, in both B. subtilis (9) and Streptococcus pneumoniae (19,25) chromosomal DNA undergoes doublestrand breaks before entering the cell as single-stranded molecules. In S. pneumoniae, circular DNA also undergoes double-strand cleavage before entry (14).…”

Section: Discussionmentioning

confidence: 99%

Linearization of donor DNA during plasmid transformation in Neisseria gonorrhoeae

1986

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We examined the fate of plasmid DNA after uptake during transformation in Neisseria gonorrhoeae. An 11.5-kilobase plasmid, pFA10, was processed to linear double-stranded DNA during uptake by competent cells, but cleavage of pFA10 was not site specific. A minority of pFA10 entered as open circles. A 42-kilobase plasmid, pFA14, was degraded into small fragments during uptake; no intracellular circular forms of pFA14 were evident. Since pFA10 DNA linearized by a restriction enzyme was not further cut during uptake, the endonucleolytic activity associated with entry of plasmid DNA appeared to act preferentially on circular DNA. Although linear plasmid DNA was taken up into a DNase-resistant state as efficiently as circular DNA, linear plasmid DNA transformed much less efficiently than circular plasmid DNA. These data suggest that during entry transforming plasmid DNA often is processed to double-stranded linear molecules; transformants may arise when some molecules are repaired to form circles. Occasional molecules which enter as intact circles may also lead to transformants.Transformation of Neisseria gonorrhoeae by plasmid DNA occurs at a low frequency relative to chromosomal DNA (4,10,27). Transformation of the gonococcus with either the beta-lactamase producing (PcD plasmid pFA3 (7.2 kilobases [kb]) or pFA10 (11.5 kb) results in plasmid deletions in about 20% of the transformants (10, 27; data not shown). When the larger 42-kb Pcr hybrid pFA14 is transformed into an isogenic recipient strain which lacks a homologous plasmid, pcr transformants are rare, and 100% of the pcr plasmids isolated from transformants are markedly deleted (4). Thus, deletions of incoming plasmids are common in gonococcal transformation, and the frequency of such deletions seems to increase with increasing size of the transformed plasmid.Although pFA14 is generally quite inefficient in transformation, it efficiently transforms recipients that contain the homologous plasmid pFA2 (4). The marked increase in efficiency of transformation by pFA14 of recipients containing pFA2 was postulated to be due to marker rescue of fragmented pFA14 DNA by the resident plasmid (4), analogous to similar phenomena described in Haemophilus influenzae (1) and Bacillus subtilis (8).Transformation of pFA3 into Escherichia coli does not result in plasmid deletions (27), suggesting that susceptibility to deletion is not an intrinsic property of these plasmids, but rather a result of processing by N. gonorrhoeae cells. Similarly, conjugal transfer of pFA3 into either gonococcal or E. coli recipients always produces a Pcr plasmid identical in size to that of the donor (27). This indicates that the pathways for plasmid entry are probably different for transformation and conjugation and suggests that the deletions found in gonococcal transformants may reflect endonucleolytic attack during entry of transforming plasmid DNA (27). In this report, we present physical evidence that circular plasmid DNA is processed to linear double-stranded DNA during uptake, and that clea...

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“…However, Morrison and Guild showed that the amount of DNA breakdown inside the cell depends on the size and quality of the donor DNA; more intact DNA gave fewer breakdown products so that a larger proportion of DNA taken up was in the form of single strands (45). In the early 1970s, they and Bill Greenberg and I independently discovered that the breakdown products of the strand complementary to the one that enters appear external to the cells (28,46). Early on, I hypothesized that a cellular DNase acted on donor DNA to facilitate entry of one strand by degrading the opposite strand (23).…”

Section: Molecular Mechanism Of Dna Uptakementioning

confidence: 99%

Rambling and Scrambling in Bacterial Transformation— a Historical and Personal Memoir

Lacks

2003

J Bacteriol

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Breakage prior to entry of donor DNA in Pneumococcus transformation

Cited by 72 publications

References 14 publications

Physiological characterization of natural transformation in Acinetobacter calcoaceticus

Physiological characterization of natural transformation in Acinetobacter calcoaceticus

Linearization of donor DNA during plasmid transformation in Neisseria gonorrhoeae

Rambling and Scrambling in Bacterial Transformation— a Historical and Personal Memoir

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