scholarly journals MinCD Proteins Control the Septation Process during Sporulation of Bacillus 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.

2021 ◽  
Vol 9 (5) ◽  
pp. 1005
Author(s):  
Olga Chervyakova ◽  
Elmira Tailakova ◽  
Nurlan Kozhabergenov ◽  
Sandugash Sadikaliyeva ◽  
Kulyaisan Sultankulova ◽  
...  

Capripoxviruses with a host range limited to ruminants have the great potential to be used as vaccine vectors. The aim of this work was to evaluate attenuated sheep pox virus (SPPV) vaccine strain NISKHI as a vector expressing several genes. Open reading frames SPPV020 (ribonucleotide kinase) and SPPV066 (thymidine kinase) were selected as sites for the insertion of foreign genes. Two integration plasmids with expression cassette were designed and constructed. Recombinant SPPVs expressing an enhanced green fluorescent protein (EGFP) (rSPPV(RRΔ)EGFP and rSPPV(TKΔ)EGFP), Foot-and-mouth disease virus capsid protein (VP1), and Brucella spp. outer membrane protein 25 (OMP25) (rSPPV(RRΔ)VP1A-(TKΔ)OMP25) were generated under the transient dominant selection method. The insertion of foreign genes into the SPPV020 and SPPV066 open reading frames did not influence the replication of the recombinant viruses in the cells. Successful foreign gene expression in vitro was assessed by luminescent microscopy (EGFP) and Western blot (VP1 and OMP25). Our results have shown that foreign genes were expressed by rSPPV both in permissive (lamb testicles) and non-permissive (bovine kidney, saiga kidney, porcine kidney) cells. Mice immunized with rSPPV(RRΔ)VP1A-(TKΔ)OMP25 elicited specific antibodies to both SPPV and foreign genes VP1 and OMP25. Thus, SPPV NISKHI may be used as a potential safe immunogenic viral vector for the development of polyvalent vaccines.


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.


1997 ◽  
Vol 17 (9) ◽  
pp. 5001-5015 ◽  
Author(s):  
N I Zanchin ◽  
P Roberts ◽  
A DeSilva ◽  
F Sherman ◽  
D S Goldfarb

The Saccharomyces cerevisiae temperature-sensitive (ts) allele nip7-1 exhibits phenotypes associated with defects in the translation apparatus, including hypersensitivity to paromomycin and accumulation of halfmer polysomes. The cloned NIP7+ gene complemented the nip7-1 ts growth defect, the paromomycin hypersensitivity, and the halfmer defect. NIP7 encodes a 181-amino-acid protein (21 kDa) with homology to predicted products of open reading frames from humans, Caenorhabditis elegans, and Arabidopsis thaliana, indicating that Nip7p function is evolutionarily conserved. Gene disruption analysis demonstrated that NIP7 is essential for growth. A fraction of Nip7p cosedimented through sucrose gradients with free 60S ribosomal subunits but not with 80S monosomes or polysomal ribosomes, indicating that it is not a ribosomal protein. Nip7p was found evenly distributed throughout the cytoplasm and nucleus by indirect immunofluorescence; however, in vivo localization of a Nip7p-green fluorescent protein fusion protein revealed that a significant amount of Nip7p is present inside the nucleus, most probably in the nucleolus. Depletion of Nip7-1p resulted in a decrease in protein synthesis rates, accumulation of halfmers, reduced levels of 60S subunits, and, ultimately, cessation of growth. Nip7-1p-depleted cells showed defective pre-rRNA processing, including accumulation of the 35S rRNA precursor, presence of a 23S aberrant precursor, decreased 20S pre-rRNA levels, and accumulation of 27S pre-rRNA. Delayed processing of 27S pre-rRNA appeared to be the cause of reduced synthesis of 25S rRNA relative to 18S rRNA, which may be responsible for the deficit of 60S subunits in these cells.


2009 ◽  
Vol 192 (1) ◽  
pp. 38-45 ◽  
Author(s):  
Melanie B. Berkmen ◽  
Catherine A. Lee ◽  
Emma-Kate Loveday ◽  
Alan D. Grossman

ABSTRACT ICEBs1 is an integrative and conjugative element found in the chromosome of Bacillus subtilis. ICEBs1 encodes functions needed for its excision and transfer to recipient cells. We found that the ICEBs1 gene conE (formerly yddE) is required for conjugation and that conjugative transfer of ICEBs1 requires a conserved ATPase motif of ConE. ConE belongs to the HerA/FtsK superfamily of ATPases, which includes the well-characterized proteins FtsK, SpoIIIE, VirB4, and VirD4. We found that a ConE-GFP (green fluorescent protein) fusion associated with the membrane predominantly at the cell poles in ICEBs1 donor cells. At least one ICEBs1 product likely interacts with ConE to target it to the membrane and cell poles, as ConE-GFP was dispersed throughout the cytoplasm in a strain lacking ICEBs1. We also visualized the subcellular location of ICEBs1. When integrated in the chromosome, ICEBs1 was located near midcell along the length of the cell, a position characteristic of that chromosomal region. Following excision, ICEBs1 was more frequently found near a cell pole. Excision of ICEBs1 also caused altered positioning of at least one component of the replisome. Taken together, our findings indicate that ConE is a critical component of the ICEBs1 conjugation machinery, that conjugative transfer of ICEBs1 from B. subtilis likely initiates at a donor cell pole, and that ICEBs1 affects the subcellular position of the replisome.


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 80 (1) ◽  
pp. 95-107 ◽  
Author(s):  
Simone Guggemoos ◽  
Frank T. Just ◽  
Antonie Neubauer

ABSTRACT The aim of the present study was to identify and functionally characterize the equine herpesvirus 1 (EHV-1) UL20 protein (UL20p). Using a specific antiserum, UL20p was shown to be associated with membranes of infected cells, as well as with envelopes of purified virions. By Western blot analysis, UL20p was detected in two main forms exhibiting M rs of 25,000 and 75,000. Both moieties did not enter the separating gel after heating of protein samples to 99°C. The slower-migrating form of UL20p contains N-linked carbohydrates, and its presence is dependent of that of other viral proteins. Infection of cells that either constitutively express UL20p or a gK-green fluorescent protein (GFP) fusion protein with various EHV-1 deletion mutants revealed a relatively stable hetero-oligomer containing gK and UL20p with an apparent M r of 75,000. As demonstrated by confocal microscopy, UL20p distribution in Rk13 cells changed from a diffuse granular or netlike appearance to a pattern confined to the Golgi network when gK was coexpressed. Analysis of a UL20 deletion mutant of EHV-1 strain RacL11 indicated an involvement of UL20p in cell-to-cell spread, as well as in very late events in virus egress. Based on these and electron microscopic studies we suggest that the EHV-1 UL20 protein might be necessary to avoid fusion of mature virions with membranes of their transport vesicles.


2006 ◽  
Vol 188 (12) ◽  
pp. 4373-4383 ◽  
Author(s):  
Krzysztof Hinc ◽  
Krzysztofa Nagórska ◽  
Adam Iwanicki ◽  
Grzegorz Węgrzyn ◽  
Simone J. Séror ◽  
...  

ABSTRACT The ability of Bacillus subtilis to form spores is a strategy for survival under unfavorable environmental conditions. It is equally crucial to break spore dormancy and return to vegetative growth at the appropriate time. Here we present data showing that the PrpE phosphatase is involved in the control of expression of genes coding for GerA receptors, which are necessary for l-alanine-induced spore germination. Moreover, PrpE is also involved in aspartic acid, glucose, fructose, and potassium (AGFK)-induced spore germination by controlling expression of genes coding for GerK receptors. In the absence of PrpE, the production of spores was essentially normal. However, l-alanine-induced spore germination and, to a lesser extent, the AGFK-induced pathway were abolished. In contrast, the germination pathway dependent on Ca2+-dipicolinate or dodecylamine remained intact. A protein phosphatase PrpE-green fluorescent protein fusion was localized to the prespore and to the dormant spore, consistent with a role in controlling expression of genes coding for GerA receptors. We propose that PrpE is an important element in a signal transduction pathway in Bacillus subtilis that controls the expression of genes coding for germination receptors.


2007 ◽  
Vol 282 (49) ◽  
pp. 36024-36036 ◽  
Author(s):  
Sunju Choi ◽  
Elisabeth A. Gustafson-Wagner ◽  
Qinchuan Wang ◽  
Shannon M. Harlan ◽  
Haley W. Sinn ◽  
...  

Targeted deletion of mXinα results in cardiac hypertrophy and cardiomyopathy with conduction defects (Gustafson-Wagner, E., Sinn, H. W., Chen, Y.-L., Wang, D.-Z., Reiter, R. S., Lin, J. L.-C., Yang, B., Williamson, R. A., Chen, J. N., Lin, C.-I., and Lin, J. J.-C. (2007) Am. J. Physiol. 293, H2680-H2692). To understand the underlying mechanisms leading to such cardiac defects, the functional domains of mXinα and its interacting proteins were investigated. Interaction studies using co-immunoprecipitation, pull-down, and yeast two-hybrid assays revealed that mXinα directly interacts with β-catenin. The β-catenin-binding site on mXinα was mapped to amino acids 535-636, which overlaps with the known actin-binding domains composed of the Xin repeats. The overlapping nature of these domains provides insight into the molecular mechanism for mXinα localization and function. Purified recombinant glutathione S-transferase- or His-tagged mXinα proteins are capable of binding and bundling actin filaments, as determined by co-sedimentation and electron microscopic studies. The binding to actin was saturated at an approximate stoichiometry of nine actin monomers to one mXinα. A stronger interaction was observed between mXinα C-terminal deletion and actin as compared with the interaction between full-length mXinα and actin. Furthermore, force expression of green fluorescent protein fused to an mXinα C-terminal deletion in cultured cells showed greater stress fiber localization compared with force-expressed GFP-mXinα. These results suggest a model whereby the C terminus of mXinα may prevent the full-length molecule from binding to actin, until the β-catenin-binding domain is occupied by β-catenin. The binding of mXinα to β-catenin at the adherens junction would then facilitate actin binding. In support of this model, we found that the actin binding and bundling activity of mXinα was enhanced in the presence of β-catenin.


2007 ◽  
Vol 189 (6) ◽  
pp. 2369-2375 ◽  
Author(s):  
Atsushi Masayama ◽  
Ritsuko Kuwana ◽  
Hiromu Takamatsu ◽  
Hisashi Hemmi ◽  
Tohru Yoshimura ◽  
...  

ABSTRACT The predicted amino acid sequence of Bacillus subtilis ycsK exhibits similarity to the GDSL family of lipolytic enzymes. Northern blot analysis showed that ycsK mRNA was first detected from 4 h after the onset of sporulation and that transcription of ycsK was dependent on SigK and GerE. The fluorescence of the YcsK-green fluorescent protein fusion protein produced in sporulating cells was detectable in the mother cell but not in the forespore compartment under fluorescence microscopy, and the fusion protein was localized around the developing spores dependent on CotE, SafA, and SpoVID. Inactivation of the ycsK gene by insertion of an erythromycin resistance gene did not affect vegetative growth or spore resistance to heat, lysozyme, or chloroform. The germination of ycsK spores in a mixture of l-asparagine, d-glucose, d-fructose, and potassium chloride and LB medium was also the same as that of wild-type spores, but the mutant spores were defective in l-alanine-stimulated germination. In addition, zymogram analysis demonstrated that the YcsK protein heterologously expressed in Escherichia coli showed lipolytic activity. We therefore propose that ycsK should be renamed lipC. This is the first study of a bacterial spore germination-related lipase.


2003 ◽  
Vol 23 (5) ◽  
pp. 1750-1763 ◽  
Author(s):  
Hilary A. Kemp ◽  
George F. Sprague,

ABSTRACT In budding yeast, diffusible mating pheromones initiate a signaling pathway that culminates in several responses, including cell cycle arrest. Only a handful of genes required for the interface between pheromone response and the cell cycle have been identified, among them FAR1 and FAR3; of these, only FAR1 has been extensively characterized. In an effort to learn about the mechanism by which Far3 acts, we used the two-hybrid method to identify interacting proteins. We identified five previously uncharacterized open reading frames, dubbed FAR7, FAR8, FAR9, FAR10, and FAR11, that cause a far3-like pheromone arrest defect when disrupted. Using two-hybrid and coimmunoprecipitation analysis, we found that all six Far proteins interact with each other. Moreover, velocity sedimentation experiments suggest that Far3 and Far7 to Far11 form a complex. The phenotype of a sextuple far3far7-far11 mutant is no more severe than any single mutant. Thus, FAR3 and FAR7 to FAR11 all participate in the same pathway leading to G1 arrest. These mutants initially arrest in response to pheromone but resume budding after 10 h. Under these conditions, wild-type cells fail to resume budding even after several days whereas far1 mutant cells resume budding within 1 h. We conclude that the FAR3-dependent arrest pathway is functionally distinct from that which employs FAR1.


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