Fate of donor DNA in pneumococcal transformation

Lacks, Sanford A.; Greenberg, Bill; Carlson, Kathryn E.

doi:10.1016/0022-2836(67)90102-7

Cited by 104 publications

(85 citation statements)

References 16 publications

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“…On the other hand, our experiments clearly show that the effects of EDTA (i.e., stimulation of DNA binding and inhibition of transformation) are caused by the removal of divalent cations from the system. Several of our observations described in this paper indicate that this removal of divalent cations affects the transformation process in part via inhibition of the Mg-dependent pneumococcal nucleases (12). At several points, our findings confirm and further develop recent observations of Morrison and Guild (2) and Lacks and Greenberg (3) conpolyallomer tubes (Beckman) were centrifuged at 37,000 rpm for 50-60 hr in a SW 50.1 rotor (Beckman) at 120.…”

Section: Discussionsupporting

confidence: 90%

Early Stages in DNA Binding and Uptake During Genetic Transformation of Pneumococci

Seto¹,

Tomasz²

1974

Proc. Natl. Acad. Sci. U.S.A.

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Ethylenediaminetetraacetate and other divalent-cation-complexing agents greatly stimulate the cellular binding of DNA molecules to competent pneumococci, while the appearance of genetic transformants and nuclease-resistant DNA binding are completely inhibited. Based on this finding, we developed an experimental system in which three early and consecutive stages of genetic transformation can be experimentally separated: (i) attachment of DNA molecules to cell surface sites that are only demonstrable in the competent state; (ii) a divalentcation-dependent nucleolytic splitting and release of the adsorbed molecules to the medium; and (iii) emergence of potential transformants accompanied by an energy-requiring and divalent-cation-dependent process in which the cell-associated DNA molecules become inaccessible to shearing forces, nucleases, anti-DNA serum, and polycations.Genetic transformation of pneumococci requires that the recipient cells be "competent" to bind and absorb extracellular DNA molecules. The molecular basis of this capacity seems to involve a subtle alteration of the cell surface, and by am propriate experiments it has been possible to identify several specific macromolecular factors that take part in this surface modification (1). While the sequential appearance of these factors seems clearly associated with the development of competence, it is not known at which stage and for what functions of the transformation process these factors are required.Such an assignment of functions is hampered by the fact that the stages of the transformation process are not well separated in time: attachment of DNA molecules is rapidly followed by an unknown number of subsequent stages. In this communication we describe an experimental system that allows a clear, temporal separation of three consecutive early phases of genetic transformation. This was made possible by our finding that EDTA (and other divalent cation complexing agents) can selectively inhibit stages 2 and 3 of genetic transformation, while allowing DNA molecules to accumulate, attached to binding sites on the cell surface. Our report fully confirms and further develops the observations made by Morrison and Guild (2) and by Lacks (3) concerning the involvement of surface-located nucleases in transformation.

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Section: Discussionsupporting

confidence: 90%

Early Stages in DNA Binding and Uptake During Genetic Transformation of Pneumococci

Seto¹,

Tomasz²

1974

Proc. Natl. Acad. Sci. U.S.A.

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“…There has been some doubt whether H. influenzae can bind foreign DNA (Schaeffer, 1958) but low competency may explain those results. Lacks, Greenberg & Carlson (1967) reported that Diplococcuspneumoniae can adsorb heterologous DNA, thus confirming an earlier finding by Lerman &Tolmach (1957). Irreversibly bound E. coZiDNA is rapidly degraded, however, presumably by exonuclease action (Lacks et al 1967).…”

Section: Introductionsupporting

confidence: 76%

“…Lacks, Greenberg & Carlson (1967) reported that Diplococcuspneumoniae can adsorb heterologous DNA, thus confirming an earlier finding by Lerman &Tolmach (1957). Irreversibly bound E. coZiDNA is rapidly degraded, however, presumably by exonuclease action (Lacks et al 1967). On the other hand, Pene & Romig (1964) reported that Bacillus cereus DNA irreversibly bound by B. subtilis does not seem to be broken down nor is it integrated.…”

Section: Introductionsupporting

confidence: 66%

Fate of Bacteriophage DNA After Adsorption by Haemophilus influenzae

Newman¹,

Stuy

1971

Journal of General Microbiology

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S U M M A R YRadioactively labelled coliphage h DNA is rapidly and irreversibly bound by competent bacteria of certain cultures of Haemophilus influenzae. The extent of adsorption in the presence of excess cells was always between 30 and 40 % of the DNA added. Bound DNA was rather resistant against degradation to acid-soluble products but the biological activity was completely lost after 60 min. incubation. Reisolated phage h DNA always banded in CsCl gradient centrifugation at a position characteristic for double stranded h DNA. It sedimented with normal or slightly reduced velocity in sucrose density gradients. Production of h phage or of infectious phage h DNA was not observed.

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“…Pneumococcal DNA is integrated by homologous recombination resulting in the local replacement of one strand of the recipient molecule by the transforming strand. The parental strand is then degraded and the nucleotides are used for de nouo DNA synthesis (Lacks et al, 1967). Heterologous DNA is degraded by endonucleases and enters the nucleotide pool.…”

Section: Discussionmentioning

confidence: 99%

Calcium regulation of growth and differentiation in Streptococcus pneumoniae

Trombe

Clavé²,

Manias³

1992

Journal of General Microbiology

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Streptococcus pneumonk requires 0.15 mM-Ca2+ in the medium for optimal growth. Increasing the Ca2+ concentration to 1 mM triggers either a differentiathe state, competence for genetic transformation during exponential growth, or partial lysis as won as the cultures enter stationary phase. Genetic and physiological data both suggest that these responses are under the control of activator@), excreted in the presence of high Ca2+ concentrations. 45Ca2+ transport is also stimulated by the activator(s). The amiloride derivative 2',4-dimethylbenzarnil (DMB) inhibits 45Ca2+ transport and prevents lysis and competence development. This provides evidence in favour of the involvement of Ca2+ transport in competence and culture lysis. On the other hand, addition of DNA to a competent culture prevents lysis of wild-type bacteria while a mutant, defective for DNA uptake, is not protected from lysis by exogenous DNA. An hypothesis is proposed for competence induction as a global metabolic response to Ca2+, under the control of competence factor.

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Fate of donor DNA in pneumococcal transformation

Cited by 104 publications

References 16 publications

Early Stages in DNA Binding and Uptake During Genetic Transformation of Pneumococci

Early Stages in DNA Binding and Uptake During Genetic Transformation of Pneumococci

Fate of Bacteriophage DNA After Adsorption by Haemophilus influenzae

Calcium regulation of growth and differentiation in Streptococcus pneumoniae

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