scholarly journals Localization of Cold Shock Proteins to Cytosolic Spaces Surrounding Nucleoids in Bacillus subtilis Depends on Active Transcription

2001 ◽  
Vol 183 (21) ◽  
pp. 6435-6443 ◽  
Author(s):  
Michael H. W. Weber ◽  
Arsen V. Volkov ◽  
Ingo Fricke ◽  
Mohamed A. Marahiel ◽  
Peter L. Graumann

ABSTRACT Using immunofluorescence microscopy and a fusion of a cold shock protein (CSP), CspB, to green fluorescent protein (GFP), we showed that in growing cells Bacillus subtilis CSPs specifically localize to cytosolic regions surrounding the nucleoid. The subcellular localization of CSPs is influenced by the structure of the nucleoid. Decondensed chromosomes in smc mutant cells reduced the sizes of the regions in which CSPs localized, while cold shock-induced chromosome compaction was accompanied by an expansion of the space in which CSPs were present. As a control, histone-like protein HBsu localized to the nucleoids, while β-galactosidase and GFP were detectable throughout the cell. After inhibition of translation, CspB-GFP was still present around the nucleoids in a manner similar to that in cold-shocked cells. However, in stationary-phase cells and after inhibition of transcription, CspB was distributed throughout the cell, indicating that specific localization of CspB depends on active transcription and is not due to simple exclusion from the nucleoid. Furthermore, we observed that nucleoids are more condensed and frequently abnormal incspB cspC and cspB cspDdouble-mutant cells. This suggests that the function of CSPs affects chromosome structure, probably through coupling of transcription to translation, which is thought to decondense nucleoids. In addition, we found that cspB cspD and cspB cspC double mutants are defective in sporulation, with a block at or before stage 0. Interestingly, CspB and CspC are depleted from the forespore compartment but not from the mother cell. In toto, our findings suggest that CSPs localize to zones of newly synthesized RNA, coupling transcription with initiation of translation.

2000 ◽  
Vol 182 (11) ◽  
pp. 3285-3288 ◽  
Author(s):  
Klaus Neuhaus ◽  
Sonja Rapposch ◽  
Kevin P. Francis ◽  
Siegfried Scherer

ABSTRACT The cellular content of major cold shock protein (MCSP) mRNA transcribed from the tandem gene duplication cspA1/A2 and growth of Yersinia enterocolitica were compared when exponentially growing cultures of this bacterium were cold shocked from 30 to 20, 15, 10, 5, or 0°C, respectively. A clear correlation between the time point when exponential growth resumes after cold shock and the degradation of cspA1/A2 mRNA was found. A polynucleotide phosphorylase-deficient mutant was unable to degradecspA1/A2 mRNA properly and showed a delay, as well as a lower rate, of growth after cold shock. For this mutant, a correlation between decreasing cspA1/A2 mRNA and restart of growth after cold shock was also observed. For both wild-type and mutant cells, no correlation of restart of growth with the cellular content of MCSPs was found. We suggest that, after synthesis of cold shock proteins and cold adaptation of the cells, MCSP mRNAs must be degraded; otherwise, they trap ribosomes, prevent translation of bulk mRNA, and thus inhibit growth of this bacterium at low temperatures.


2005 ◽  
Vol 187 (6) ◽  
pp. 2163-2174 ◽  
Author(s):  
Ayako Nishibori ◽  
Jin Kusaka ◽  
Hiroshi Hara ◽  
Masato Umeda ◽  
Kouji Matsumoto

ABSTRACT Application of the cardiolipin (CL)-specific fluorescent dye 10-N-nonyl-acridine orange has recently revealed CL-rich domains in the septal regions and at the poles of the Bacillus subtilis membrane (F. Kawai, M. Shoda, R. Harashima, Y. Sadaie, H. Hara, and K. Matsumoto, J. Bacteriol. 186:1475-1483, 2004). This finding prompted us to examine the localization of another phospholipid, phosphatidylethanolamine (PE), with the cyclic peptide probe, Ro09-0198 (Ro), that binds specifically to PE. Treatment with biotinylated Ro followed by tetramethyl rhodamine-conjugated streptavidin revealed that PE is localized in the septal membranes of vegetative cells and in the membranes of the polar septum and the engulfment membranes of sporulating cells. When the mutant cells of the strains SDB01 (psd1::neo) and SDB02 (pssA10::spc), which both lack PE, were examined under the same conditions, no fluorescence was observed. The localization of the fluorescence thus evidently reflected the localization of PE-rich domains in the septal membranes. Similar PE-rich domains were observed in the septal regions of the cells of many Bacillus species. In Escherichia coli cells, however, no PE-rich domains were found. Green fluorescent protein fusions to the enzymes that catalyze the committed steps in PE synthesis, phosphatidylserine synthase, and in CL synthesis, CL synthase and phosphatidylglycerophosphate synthase, were localized mainly in the septal membranes in B. subtilis cells. The majority of the lipid synthases were also localized in the septal membranes; this includes 1-acyl-glycerol-3-phosphate acyltransferase, CDP-diacylglycerol synthase, phosphatidylserine decarboxylase, diacylglycerol kinase, glucolipid synthase, and lysylphosphatidylglycerol synthase. These results suggest that phospholipids are produced mostly in the septal membranes and that CL and PE are kept from diffusing out to lateral ones.


2006 ◽  
Vol 188 (1) ◽  
pp. 240-248 ◽  
Author(s):  
Karen Hunger ◽  
Carsten L. Beckering ◽  
Frank Wiegeshoff ◽  
Peter L. Graumann ◽  
Mohamed A. Marahiel

ABSTRACT The nucleic acid binding cold shock proteins (CSPs) and the cold-induced DEAD box RNA helicases have been proposed separately to act as RNA chaperones, but no experimental evidence has been reported on a direct cooperation. To investigate the possible interaction of the putative RNA helicases CshA and CshB and the CSPs from Bacillus subtilis during cold shock, we performed genetic as well as fluorescence resonance energy transfer (FRET) experiments. Both cshA and cshB genes could be deleted only in the presence of a cshB copy in trans, showing that the presence of one csh gene is essential for viability. The combined gene deletion of cshB and cspD resulted in a cold-sensitive phenotype that was not observed for either helicase or csp single mutants. In addition to the colocalization of the putative helicases CshA and CshB with CspB and the ribosomes in areas surrounding the nucleoid, we detected a strong FRET interaction in vivo between CshB and CspB that depended on active transcription. In contrast, a FRET interaction was not observed for CshB and the ribosomal protein L1. Therefore, we propose a model in which the putative cold-induced helicases and the CSPs work in conjunction to rescue misfolded mRNA molecules and maintain proper initiation of translation at low temperatures in B. subtilis.


1998 ◽  
Vol 180 (20) ◽  
pp. 5327-5333 ◽  
Author(s):  
Imrich Barák ◽  
Peter Prepiak ◽  
Falko Schmeisser

ABSTRACT Mutation of the divIVB locus in Bacillus subtilis causes misplacement of the septum during cell division and allows the formation of anucleate minicells. The divIVBlocus contains five open reading frames (ORFs). The last two ORFs (minCD) are homologous to minC andminD of Escherichia coli but a minEhomolog is lacking in B. subtilis. There is some similarity between minicell formation and the asymmetric septation that normally occurs during sporulation in terms of polar septum localization. However, it has been proposed that MinCD has no essential role in sporulation septum formation. We have used electron microscopic studies to show septation events during sporulation in some minDstrains. We have observed an unusually thin septum at the midcell position in minD and also in minD spoIIE71mutant cells. Fluorescence microscopy also localized a SpoIIE-green fluorescent protein fusion protein at the midcell site inminD cells. We propose that the MinCD complex plays an important role in asymmetric septum formation during sporulation ofB. subtilis cells.


2002 ◽  
Vol 184 (7) ◽  
pp. 1998-2004 ◽  
Author(s):  
Takako Murakami ◽  
Koki Haga ◽  
Michio Takeuchi ◽  
Tsutomu Sato

ABSTRACT The Bacillus subtilis spoIIIJ gene, which has been proven to be vegetatively expressed, has also been implicated as a sporulation gene. Recent genome sequencing information in many organisms reveals that spoIIIJ and its paralogous gene, yqjG, are conserved from prokaryotes to humans. A homologue of SpoIIIJ/YqjG, the Escherichia coli YidC is involved in the insertion of membrane proteins into the lipid bilayer. On the basis of this similarity, it was proposed that the two homologues act as translocase for the membrane proteins. We studied the requirements for spoIIIJ and yqjG during vegetative growth and sporulation. In rich media, the growth of spoIIIJ and yqjG single mutants were the same as that of the wild type, whereas spoIIIJ yqjG double inactivation was lethal, indicating that together these B. subtilis translocase homologues play an important role in maintaining the viability of the cell. This result also suggests that SpoIIIJ and YqjG probably control significantly overlapping functions during vegetative growth. spoIIIJ mutations have already been established to block sporulation at stage III. In contrast, disruption of yqjG did not interfere with sporulation. We further show that high level expression of spoIIIJ during vegetative phase is dispensable for spore formation, but the sporulation-specific expression of spoIIIJ is necessary for efficient sporulation even at the basal level. Using green fluorescent protein reporter to monitor SpoIIIJ and YqjG localization, we found that the proteins localize at the cell membrane in vegetative cells and at the polar and engulfment septa in sporulating cells. This localization of SpoIIIJ at the sporulation-specific septa may be important for the role of spoIIIJ during sporulation.


Microbiology ◽  
2005 ◽  
Vol 151 (3) ◽  
pp. 999-1012 ◽  
Author(s):  
Dirk-Jan Scheffers

During Bacillus subtilis spore formation, many membrane proteins that function in spore development localize to the prespore septum and, subsequently, to the outer prespore membrane. Recently, it was shown that the cell-division-specific penicillin-binding proteins (PBPs) 1 and 2b localize to the asymmetric prespore septum. Here, the author studied the localization of other PBPs, fused to green fluorescent protein (GFP), during spore formation. Fusions to PBPs 4, 2c, 2d, 2a, 3, H, 4b, 5, 4a, 4* and X were expressed during vegetative growth, and their localization was monitored during sporulation. Of these PBPs, 2c, 2d, 4b and 4* have been implicated as having a function in sporulation. It was found that PBP2c, 2d and X changed their localization, while the other PBPs tested were not affected. The putative endopeptidase PbpX appears to spiral out in a pattern that resembles FtsZ redistribution during sporulation, but a pbpX knockout strain had no distinguishable phenotype. PBP2c and 2d localize to the prespore septum and follow the membrane during engulfment, and so are redistributed to the prespore membrane. A similar pattern was observed when GFP–PBP2c was expressed in the mother cell from a sporulation-specific promoter. This work shows that various PBPs known to function during sporulation are redistributed from the cytoplasmic membrane to the prespore.


2020 ◽  
Vol 203 (2) ◽  
pp. e00463-20
Author(s):  
Amit Bhambhani ◽  
Isabella Iadicicco ◽  
Jules Lee ◽  
Syed Ahmed ◽  
Max Belfatto ◽  
...  

ABSTRACTPrevious work identified gene product 56 (gp56), encoded by the lytic bacteriophage SP01, as being responsible for inhibition of Bacillus subtilis cell division during its infection. Assembly of the essential tubulin-like protein FtsZ into a ring-shaped structure at the nascent site of cytokinesis determines the timing and position of division in most bacteria. This FtsZ ring serves as a scaffold for recruitment of other proteins into a mature division-competent structure permitting membrane constriction and septal cell wall synthesis. Here, we show that expression of the predicted 9.3-kDa gp56 of SP01 inhibits later stages of B. subtilis cell division without altering FtsZ ring assembly. Green fluorescent protein-tagged gp56 localizes to the membrane at the site of division. While its localization does not interfere with recruitment of early division proteins, gp56 interferes with the recruitment of late division proteins, including Pbp2b and FtsW. Imaging of cells with specific division components deleted or depleted and two-hybrid analyses suggest that gp56 localization and activity depend on its interaction with FtsL. Together, these data support a model in which gp56 interacts with a central part of the division machinery to disrupt late recruitment of the division proteins involved in septal cell wall synthesis.IMPORTANCE Studies over the past decades have identified bacteriophage-encoded factors that interfere with host cell shape or cytokinesis during viral infection. The phage factors causing cell filamentation that have been investigated to date all act by targeting FtsZ, the conserved prokaryotic tubulin homolog that composes the cytokinetic ring in most bacteria and some groups of archaea. However, the mechanisms of several phage factors that inhibit cytokinesis, including gp56 of bacteriophage SP01 of Bacillus subtilis, remain unexplored. Here, we show that, unlike other published examples of phage inhibition of cytokinesis, gp56 blocks B. subtilis cell division without targeting FtsZ. Rather, it utilizes the assembled FtsZ cytokinetic ring to localize to the division machinery and to block recruitment of proteins needed for septal cell wall synthesis.


2003 ◽  
Vol 66 (11) ◽  
pp. 2045-2050 ◽  
Author(s):  
YI ZHANG ◽  
MANSEL W. GRIFFITHS

Heat shock proteins play an important role in protecting bacterial cells against several stresses, including starvation. In this study, the promoters for two genes encoding heat shock proteins involved in many stress responses, UspA and GrpE, were fused with the green fluorescent protein (gfp) gene. Thus, the expression of the two genes could be quantified by measuring the fluorescence emitted by the cells under different environmental conditions. The heat resistance levels of starved and nonstarved cells during storage at 5, 10, and 37°C were compared with the levels of expression of the uspA and grpE genes. D52-values (times required for decimal reductions in count at 52°C) increased by 11.5, 14.6, and 18.5 min when cells were starved for 3 h at 37°C, for 24 h at 10°C, and for 2 days at 5°C, respectively. In all cases, these increases were significant (P < 0.01), indicating that the stress imposed by starvation altered the ability of E. coli O157:H7 to survive subsequent heat treatments. Thermal tolerance was correlative with the induction of UspA and GrpE. At 5°C, the change in the thermal tolerance of the pathogen was positively linked to the induced expression of the grpE gene but negatively related to the expression of the uspA gene. The results obtained in this study indicate that UspA plays an important role in starvation-induced thermal tolerance at 37°C but that GrpE may be more involved in regulating this response at lower temperatures. An improvement in our understanding of the molecular mechanisms involved in these cross-protection responses may make it possible to devise strategies to limit their effects.


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