Absence of Transient Elevated UV Resistance during Germination of
            <i>Bacillus subtilis</i>
            Spores Lacking Small, Acid-Soluble Spore Proteins α and β

Setlow, Barbara; Setlow, Peter

doi:10.1128/jb.170.6.2858-2859.1988

Cited by 11 publications

(14 citation statements)

References 12 publications

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“…8; data not shown). However, this analysis only detects the extremely UV-resistant spores which transiently exist early in spore germination; even late in germination the survivors of the huge UV dose used in analysis of transient UV resistance are those spores triggering germination well after addition of germinant (18). Consequently, it was possible that the total population of germinated gpr spores might be somewhat moUV re sistant than that of germinated gpr+ spores.…”

Section: Resultsmentioning

confidence: 99%

“…We also monitored the transient UV resistance during germination of gpr and gpr) spores, since this has been suggested to be a reflection of a conformational change in DNA early in germination, a conformational change dependent on a/P-type SASP (18,23). With both species gpr and gpr+ spores exhibited nearly identical transient UV resistance during germination ( Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The SASP most likely to be having this effect were alP-type SASP, since these can block growth in Escherichia coli and inhibit many reactions involving DNA in vitro (16,20). In contrast, y-type SASP have no effect in E. coli, and do not interact with DNA in vivo or in vitro (14,18). In order to test this possibility directly, we introduced the gpr mutation into a B. subtilis strain lacking the two major alp-type SASP, a and p (ap-p-strain).…”

Section: Resultsmentioning

confidence: 99%

“…The UV resistance of spores during germination was determined as previously described (18), and survivors were enumerated by plating on 2 x YT medium plates plus the appropriate antibiotic as noted above. Samples (-3 x 105 cpm) of [3H]thymidine-labeled B. subtilis dormant spores or spores germinated in 2 x YT plus 4 mM L-alanine as described above were irradiated with UV light primarily at 254 nm, and the dosages given were determined as previously described (17).…”

mentioning

confidence: 99%

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Properties of Bacillus megaterium and Bacillus subtilis mutants which lack the protease that degrades small, acid-soluble proteins during spore germination

et al. 1992

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During germination of spores of Bacillus species the degradation of the spore's pool of small, acid-soluble proteins (SASP) is initiated by a protease termed GPR, the product of the gpr gene. Bacillus megaterium and B. subtilis mutants with an inactivated gpr gene grew, sporulated, and triggered spore germination as did gpr+ strains. However, SASP degradation was very slow during germination ofgpr mutant spores, and in rich media the time taken for spores to return to vegetative growth (defined as outgrowth) was much longer in gpr than in gpr+ spores. Not surprisingly, gpr spores had much lower rates of RNA and protein synthesis during outgrowth than did gpr+ spores, although both types of spores had similar levels of ATP. The rapid decrease in the number of negative supertwists in plasmid DNA seen during germination of gpr+ spores was also much slower in gpr spores. Additionally, UV irradiation of gpr B. subtilis spores early in germination generated significant amounts of spore photoproduct and only small amounts of thymine dimers (TT); in contrast UV irradiation of germinated gpr+ spores generated almost no spore photoproduct and three to four times more TT. Consequently, germinated gpr spores were more UV resistant than germinated gpr+ spores. Strikingly, the slow outgrowth phenotype of B. subtilis gpr spores was suppressed by the absence of major od/,-type SASP. These data suggest that (i) a$/,-type SASP remain bound to much, although not all, of the chromosome in germinated gpr spores; (ii) the a$d-type SASP bound to the chromosome in gpr spores alter this DNA's topology and UV photochemistry; and (iii) the presence of o/,-type SASP on the chromosome is detrimental to normal spore outgrowth.Approximately 10 to 20% of the protein of dormant spores of Bacillus species is degraded to free amino acids in the first minutes of spore germination (22). These amino acids can support much of the protein synthesis early in the development of the germinating and outgrowing spore (22). The proteins degraded in this process are a group of small, acid-soluble proteins (SASP) of two types, al and y (22). There are multiple ao/-type SASP in spores of Bacillus species, and the amino acid sequences of these proteins have been highly conserved both within and across species (22). The aJ,-type SASP are associated with spore DNA and play a key role in the resistance of spores to UV light (22, 23). Bacillus spores have only one y-type SASP, and the primary sequence of this protein has not been as highly conserved in evolution as has those of a/P-type SASP. -y-Type SASP are not associated with DNA in vivo and have no known function other than generating amino acids by their degradation during spore germination.The great majority, if not all, SASP degradation during spore germination is initiated by a single protease, which has been termed GPR (8,9,22). This enzyme is an endoprotease specific for a pentapeptide sequence found once or twice in all SASP. GPR is initially synthesized during sporulation as a 46-kDa precursor (termed P...

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Properties of Bacillus megaterium and Bacillus subtilis mutants which lack the protease that degrades small, acid-soluble proteins during spore germination

et al. 1992

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“…change in the DNA from an A-like to a B-like conformation; not surprisingly, this transient period of decreased DNA photoreactivity is absent during germination of a~P" spores in which much of the DNA in the dormant spores presumably already exists in a B-like conformation (Setlow and Setlow, 1988).…”

Section: Small Acid-soluble Proteins Involved In A-dna Formation In Bmentioning

confidence: 99%

DNA in dormant spores of Bacillus species is in an A‐like conformation

Setlow

1992

Molecular Microbiology

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SummaryThe DNA in dormant spores of Bacillus species is associated with a/|3-type smaii, acid-soiuble proteins (SASP), which are double-stranded DNA-binding proteins whose amino acid sequence has been highly conserved in evolution. In vitro these proteins bind most strongly to DNA which readily adopts an A-iike conformation, as binding of a/|3-type SASP causes DNA to assume an A-like conformation. As predicted by this conformational change in DNA, binding of a/ptype SASP to relaxed but covalently closed plasmid DNA results in the introduction of a iarge number of negative supercoils. Associated with the conformational change in DNA brought about by oc/^-type SASP binding is a change in its photochemistry such that ultraviolet irradiation does not generate pyrimidine dimers, but rather a thyminyl-thymine adduct termed spore photoproduct (SP). The latter two properties of DNA complexed with o(/|3-type SASP in vitro are similar to those of DNA in dormant spores of Baciiius species in which: (i) plasmid DNA has a much higher number of negative supercoils than plasmid in growing cells; and (ii) ultraviolet irradiation produces SP and no pyrimidine dimers, while only pyrimidine dimers are formed in growing cells. During sporulation these changes in the properties of spore DNA take place in parallel with synthesis of a/ptype SASP, and the magnitude of the changes is greatly reduced in mutants that make low amounts of these proteins. A straightforward interpretation of these data is that DNA in dormant spores of Bacillus species is in an A-like conformation. DNA in an A-like conformation is also present in growing cells with high a/|3-type SASP levels. However, the presence of this A-like DNA is detrimental to cell growth.

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Resistance of spores of Bacillus species to ultraviolet light

Setlow

2001

Environ and Mol Mutagen

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169

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Dormant spores of the various Bacillus species, including B. subtilis, are 5 to 50 times more resistant to UV radiation than are the corresponding growing cells. This elevated spore UV resistance is due to: a) the photochemistry of DNA within spores, as UV generates few if any cyclobutane dimers, but rather a photoproduct (Fig. 1) called spore photoproduct (SP; 5-thyminyl-5,6-dihydrothymine); and b) DNA repair, in particular SP-specific repair, during spore germination. The novel UV photochemistry of spore DNA is largely due to its saturation with a group of small, acid-soluble proteins (SASP), which are unique to spores and whose binding alters the DNA conformation and thus its photochemistry. SP-specific repair is also unique to spores and is carried out by a light-independent SP-lyase, an iron-sulfur protein that utilizes S-adenosylmethionine to catalyze SP monomerization without DNA backbone cleavage.

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Absence of Transient Elevated UV Resistance during Germination of Bacillus subtilis Spores Lacking Small, Acid-Soluble Spore Proteins α and β

Cited by 11 publications

References 12 publications

Properties of Bacillus megaterium and Bacillus subtilis mutants which lack the protease that degrades small, acid-soluble proteins during spore germination

Properties of Bacillus megaterium and Bacillus subtilis mutants which lack the protease that degrades small, acid-soluble proteins during spore germination

DNA in dormant spores of Bacillus species is in an A‐like conformation

Resistance of spores of Bacillus species to ultraviolet light

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