Genetic mapping in Bacillus subtilis

Dubnau, David; Goldthwaite, Claire; Smith, Issar; Marmur, Julius

doi:10.1016/0022-2836(67)90358-0

Cited by 217 publications

(100 citation statements)

References 28 publications

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“…1), suggesting that the order is metE-bioB-aroG-argA or, less likely, bioBaroG-argA-metE. Since thr-5 was linked to metE (91%) ( Table 2), but not to argA (5), thr-S is closer to metE than to argA, suggesting the order thr-5-metE-bioB-aroG-argA (Fig. 1).…”

Section: Resultsmentioning

confidence: 97%

Genetic mapping and physiological consequences of metE mutations of Bacillus subtilis

et al. 1988

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Three metE mutations ofBacillus subtlis, which cause cells to have a 25-to 200-fold decrease in L-methionine S-adenosyltransferase (EC 2.5.1.6) activity, were mapped between bioB and thr. The corresponding three metE mutants contained three-to fourfold less intracellular S-adenosylmethionine (SAM) but at least sevenfold more methionine than the metE+ strain when grown in synthetic medium. This indicates a strong feedback control of SAM on its synthesis. However, only the metE2 strain, with the lowest SAM concentration, grew at a slightly lower rate than the parent, which showed that an intracellular concentration of about 25 ,uM SAM was critical for growth at the normal rate. Neither DNA methylation (measured by bacteriophage +105 restriction) nor sporulation was affected at this low SAM concentration. Addition of methionine to the growth medium caused an increase in the pool of SAM in some but not all metE mutants. Coaddition of adenine did not change this result. However, the extent of sporulation (induced by mycophenolic acid) was decreased 50-fold in all mutants by the addition of methionine and adenine. Therefore, the combination of methionine and adenine suppresses sporulation regardless of whether it causes an increase in the level of SAM.In previous work from this laboratory, exposure of a Bacillus subtilis relAl strain (strain 61885; for detailed genotypes, see Table 1) to ethionine (optimal concentration, 1 mM) greatly (104 fold) increased the sporulation frequency (in the presence of glucose, which normally represses sporulation) and caused a decrease in L-methionine S-adenosyltransferase (SAM synthetase; EC 2.5.1.6) activity (20). Cells of a "metEl" mutant (strain 62258), isolated by resistance to the methionine (Met) analog ethionine at 10 mM, had greatly decreased S-adenosylmethionine (SAM) synthetase activity and sporulated spontaneously (in the presence of glucose) at about a 10-fold-higher frequency than its parent (strain 61885) (20). The increased sporulation frequency apparently depended on the metEl mutation, because a transformant (strain 62302), isolated by transformation of a different relAl strain (strain 62262) with DNA of the "metEl" mutant (strain 62258) and plating on 10 mM ethionine, also showed elevated spontaneous sporulation (20). These results were interpreted as indicating that the decrease of SAM synthetase activity was responsible for the increased spontaneous sporulation. Furthermore, addition of SAM or of the SAM precursors Met and adenosine, greatly decreased this sporulation, suggesting that increased SAM levels in the cells may suppress sporulation (20).It was later realized that the original parent (strain 61885) already contained a mutation (called ethAl) which caused resistance to intermediate (2 mM) ethionine concentrations and was required for the continual sporulation caused by ethionine. The sporulation resulted from the production of S-adenosylethionine rather than from the decrease of intra-* Corresponding author. cellular SAM levels and did not simply depend on...

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Section: Resultsmentioning

confidence: 97%

Genetic mapping and physiological consequences of metE mutations of Bacillus subtilis

et al. 1988

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“…Unfortunately, no Spstage IV mutations were closely linked to the phe-12 marker (Table 3) so the group loosely linked to this marker and which included both Sp-and Osp mutations had to be studied. It was assumed that the mutations loosely linked by transduction to the phe-12 marker would not be linked to this marker by transformation in which a much smaller piece of DNA is transferred than in PBS-I transduction (Dubnau, Goldthwaite, Smith & Marmur, 1967)-The unavailability of a linked marker for these mutations prompted the use of the recombination index method (see Methods). This procedure avoids variations in competence of recipients and variations in efficiency of DNA preparations by relating the transfer of a given marker to the transfer of an outside unlinked marker, in this case tryptophan dependence.…”

Section: Resultsmentioning

confidence: 99%

Sporulation in Bacillus subtilis. Genetic Analysis of Oligosporogenous Mutants

Coote

1972

Journal of General Microbiology

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“…It can be seen that the markers mapped so far fall into two distinct groups situated towards each end of the chromosome. It is interesting to note that ade occurs towards the beginning of the chromosome as do the ade markers of Bacillus subtilis (Dubnau et al 1967;O'Sullivan & Sueoka, 1967), but the streptomycin and erythromycin loci are not similar in their positions nor in their order. More markers will be mapped in this way, and the presence of linkage between the markers is being looked for.…”

Section: Discussionmentioning

confidence: 98%

“…Linkage groups have so far only been described comparatively rarely, and hence it is necessary to apply one of the supporting techniques. Such techniques that have already been applied to the mapping of Bacillus subtilis include marker frequency (Yoshikawa & Sueoka, 1963 a, b) and density shift (Yoshikawa & Dubnau, Goldthwaite, Smith & Marmur, 1967), and the technique chosen in this study was that of density shift. When this method was first formulated, it was thought that the bacterial chromosome replicated uni-directionally from a single initiation point (Cairns, 1963a, b ;Nagata, 1963;Yoshikawa & Sueoka, 1963a, b), and hence the replication order of the markers would be identical to the genetical order.…”

Section: Introductionmentioning

confidence: 99%

Mapping of the Pneumococcus Chromosome: Application of the Density-shift Method

Butler

Smiley

1973

Journal of General Microbiology

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SUMMARYConditions have been investigated which allow the mapping of the replication order of the genes on the pneumococcal chromosome by the density-shift method. Adequate synchrony of DNA replication was achieved by using cultures already involved in the strict regime designed to give competent cells; such cultures were grown for 30 min into the stationary phase and then diluted into the medium in which the density-shift will occur. The shift was achieved by changing from either (i) 'light' peptone medium to synthetic medium containing 5-BU, or (ii) peptone medium prepared in D,O to ' light' peptone medium. Samples of such cultures were lysed and centrifuged in caesium chloride and the gradients so formed fractionated and analysed for the transforming activity for the genetic markers. A map giving the order of replication of eleven markers is described.

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Genetic mapping in Bacillus subtilis

Cited by 217 publications

References 28 publications

Genetic mapping and physiological consequences of metE mutations of Bacillus subtilis

Genetic mapping and physiological consequences of metE mutations of Bacillus subtilis

Sporulation in Bacillus subtilis. Genetic Analysis of Oligosporogenous Mutants

Mapping of the Pneumococcus Chromosome: Application of the Density-shift Method

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