Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
Correspondence
Jeffery Errington
jeff.errington{at}pathology.ox.ac.uk
![]() |
ABSTRACT |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
![]() |
INTRODUCTION |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
On starvation, a developmental process called sporulation is initiated, and early in sporulation, the medial FtsZ ring disassembles and spirals out towards the cell poles, where it reassembles into a ring structure near both cell poles (Ben-Yehuda & Losick, 2002). The shift in position of the Z-ring depends both on an increase in FtsZ expression levels, and on the sporulation-specific SpoIIE protein. SpoIIE is an integral membrane protein that interacts directly with FtsZ (Lucet et al., 2000
), and it has been known for several years that polar FtsZ ring formation and asymmetric division are impaired in spoIIE-null mutants (Barak & Youngman, 1996
; Feucht et al., 1996
; Khvorova et al., 1998
). Additionally, SpoIIE plays a key role in
F activation (reviewed by Errington, 2003
).
So far, three factors that act negatively on FtsZ ring formation have been described in B. subtilis: the Min system, the nucleoid and the Z-ring-associated protein EzrA. The Min system consists of three proteins, MinC, MinD and DivIVA, which prevent cell division near the cell pole (Marston & Errington, 1999). Recently, Wu & Errington (2004)
identified a protein, Noc, that associates non-specifically with the nucleoid, and is required to inhibit cell division in its vicinity. EzrA is a membrane protein that interacts directly with FtsZ to prevent polymerization and aberrant FtsZ formation (Haeusser et al., 2004
).
The role of FtsZ in assembly and constriction of the division machinery is still not fully understood, and the above survey shows that there are a myriad of potential proteinprotein interactions involving FtsZ, of which only a few have been characterized in any detail. The isolation of point mutations in ftsZ with subtle effects on phenotype might provide an important tool to analyse FtsZ function. Most previous genetic studies of ftsZ have focused on the isolation of mutants with severe division defects (Stricker & Erickson, 2003).
In this paper, we describe a new approach to the isolation of ftsZ mutants in B. subtilis, and describe nine new ftsZ mutants that are viable, and have mild, but potentially informative, phenotypes.
![]() |
METHODS |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
|
Sporulation and -galactosidase assay.
Sporulation was induced by growth in CH, followed by resuspension in a starvation medium (SM) (Partridge & Errington, 1993; Sterlini & Mandelstam, 1969
). Time zero (t0) was defined as the point at which the cells were resuspended in the SM. Measurement of septum formation and sporulation frequency was performed as described previously (Feucht et al., 2002
).
-Galactosidase activity was assayed using a method described by Errington & Mandelstam (1986)
. One unit of
-galactosidase catalyses the production of 1 nmol 4-methylumbelliferone min1.
Western blot analysis.
Strains were inoculated in PAB, and grown for 3 h at 37 °C. Culture samples (0·5 ml) were taken, boiled (5 min), and equal amounts of proteins were loaded and separated by 10 % SDS-PAGE. The amount of protein was determined by a Bio-Rad assay. The proteins were then transferred to Hybond-C membranes (Amersham), and subjected to immunoblotting with polyclonal anti-FtsZ antibodies, which were used at a dilution 1 : 2000. Alkaline-phosphatase-conjugated antibodies were used as secondary antibodies, and blots were developed by exposure to ECL substrate (Amersham).
Microscopy.
For phase-contrast and fluorescence visualization, samples of live cells were examined either on glass slides pre-treated with polysine, or on a thin film of 1·2 % agarose. Membranes were stained with FM5-95 (final concentration 90 µg ml1; Molecular Probes) by adding the dye at least 20 min prior to microscopy examination. Nucleoids were stained by adding 3 µl 4',6-diamidino-2-phenylindole (DAPI; 1 µg ml1 in 50 %, v/v, glycerol; Sigma) to 9 µl cells for 1 min before viewing. Images were acquired using a Sony CoolSnap HQ cooled CCD camera (Roper Scientific) attached to an Axiovert 135TV inverted microscope (Zeiss) and METAMORPH version 4.6 software (Universal Imaging Corporation). Rabbit polyclonal anti-FtsZ antibodies were used for immunofluorescence microscopy (IFM) at a dilution of 1 : 400. Fixation, permeabilization and immunofluorescence staining of cells were performed as described previously (Lewis & Errington, 1996; Pogliano et al., 1995
; Resnekov et al., 1996
), except that the glutaraldehyde concentration was reduced to 0·005 %.
![]() |
RESULTS |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
In parallel, the mutated plasmid library was also transformed into host strains 1901 and 2770 containing deletions of minD and minCD, respectively. Both strains are slightly impaired in sporulation (Levin et al., 1998; Thomaides et al., 2001
). Transformants were grown at 37 °C, and screened for altered sporulation frequency on the basis of colony appearance. Around 4500 and 9000 transformants were screened, yielding three mutations (ftsZ5, ftsZ20 and ftsZ38) from the minD mutant, and one (ftsZ8) from the minCD mutant. All of the mutants appeared to be further impaired in sporulation than the parental strain on NA. The mutations were crossed into the minCD+ strain 1272. Segregation of mutations ftsZ5, ftsZ20 and ftsZ38 into colonies with normal and reduced sporulation efficiency showed that these mutations also had an effect in the wild-type background, and lay within the ftsZ locus. Mutation ftsZ8, which produced only a slight sporulation defect in 2770, did not have a detectable phenotype in the wild-type background. Therefore the presence of the mutation was confirmed by sequencing the ftsZ gene of four transformants.
DNA sequencing (Table 2) revealed that only one of the new ftsZ alleles, ftsZ20, would produce a substitution (V38A) in the N-terminal domain of the protein. Allele ftsZ5 (D174N) would affect the beginning of the core helix H7 that connects the N- and C-terminal domains of FtsZ. Six of the other seven alleles had mutations that would affect residues in the less-characterized C-terminal domain of FtsZ. The exception, ftsZ38, had two mutations: L302P, which lay close to the ftsZ6 mutation, and Q353R, which lay in the extreme C-terminus, for which no structural data are available. The substitution V38A (ftsZ20) is in an amino acid position that is highly conserved between other organisms for which genome sequences are available (Vaughan et al., 2004
). The changes I245F (ftsZ24), V260A (ftsZ3), E300K (ftsZ6), L302P (ftsZ38) are in less-conserved residues, whereas D174N (ftsZ5), S219L (ftsZ8), S271R (ftsZ11), A285T (ftsZ4) and Q353R (ftsZ38) are not conserved (Vaughan et al., 2004
).
|
|
Cells producing FtsZV38A protein (ftsZ20) had a slightly increased cell length (Fig. 1M, N). Around 15 % of sister cells appeared to divide in a twisted manner to produce a seagull morphology (white arrows). Twisted divisions appeared to occur in both shorter and longer cells. Some of the twisted divisions trapped DNA in the septum (upper white arrow). Many cells had a misshaped pole with a pointed tip or a tilted minicell-like appendage (black arrow).
As shown in Fig. 1(O), the ftsZ5 mutant (FtsZD174N), when first isolated in the minD background, formed long filaments. The phenotype was less severe in the wild-type background, and the cells were only slightly longer, on average, than the wild-type (Fig. 1P
). Staining the membranes of the cells with the dye FM5-95 showed that some of the longer cells occasionally formed a septum (Fig. 1Q
). Perhaps because of the impairment in division, ftsZ5 mutant colonies appeared to be unstable in both minD and wild-type backgrounds when propagated on NA (with or without chloramphenicol selection).
Exponentially growing cells producing FtsZE300K (ftsZ6; Fig. 1R, S) and FtsZS271R (ftsZ11; Fig. 1T, U
) mutant proteins formed a mixture of short wild-type-like cells and long filaments with few division septa (as seen by staining the membranes with FM9-95; Fig. 1S, U
). In addition, production of FtsZE300K (ftsZ6) protein generated in some cells twisted divisions, either within or near the end of the cell filament, again forming tilted minicell-like appendages (arrows). This mutant also appeared to be unstable on NA, whereas the ftsZ11 mutant strain was stable.
As some of the ftsZ mutant strains were unstable, all cultures were propagated in liquid PAB medium for minimal periods of time. As a further check on the reproducibility of the phenotypes, the mutants were also examined directly from NA, and also immediately after growth on the primary transformation plates, yielding similar findings (data not shown).
It has been shown that lowering or increasing FtsZ expression levels causes filamentation or an increase in minicell formation, respectively (Palacios et al., 1996; Ward & Lutkenhaus, 1985
; Weart & Levin, 2003
). Therefore, FtsZ protein levels in the various mutants were examined by Western blotting (Fig. 2
). All of the mutants appeared to produce normal levels of FtsZ. Suprisingly, the FtsZL302P-Q353R protein (ftsZ38) ran at a higher molecular mass position, suggesting that the tertiary structure of this mutant protein might be altered or more resistant to SDS treatment. Sequencing of the ftsZ38 gene from the chromosome verified the absence of any duplicated sequences.
|
|
A number of mutant proteins [FtsZL302P-Q353R (ftsZ38), FtsZS219L (ftsZ8) and FtsZV38A (ftsZ20)] formed helical FtsZ structures with one to two turns at mid-cell, in addition to normal FtsZ bands. The FtsZL302P-Q353R protein (ftsZ38) generated the weakest phenotype, with few helical FtsZ structures (Fig. 3H). The FtsZS219L protein (ftsZ8) formed helical structures in many cells, but they also usually had abnormal amounts of FtsZ at the poles (Fig. 3J
). Interestingly, the gross morphology of this strain was nearly indistinguishable from that of the wild-type strain (apart from a few minicells), suggesting that the helical FtsZ structures at mid-cell eventually generate near-normal cell divisions. Production of the FtsZV38A protein (ftsZ20) caused the most severe defect, with most cells exhibiting helical FtsZ structures or double FtsZ bands (Fig. 3L
), which also appeared to be helical structures when the focal plane was varied (not shown). Again, the near-normal length of the cells of this mutant supports the notion that the helical FtsZ rings usually lead to division. However, in this case the topology of division reflected the shape of the FtsZ structures, and many of the cells formed abnormal, twisted septa (see above).
The FtsZD174N protein (ftsZ5) formed a range of abnormal structures and accumulations of FtsZ (Fig. 3N). As cultures of this mutant included normal but also longer cells, some of the FtsZ structures are presumably non-functional.
Elongated helical FtsZ structures were particularly evident in mutant cells producing FtsZS271R (ftsZ11) mutant protein. The helices often overlapped the area occupied by the DNA (white bars in Fig. 3P, Q). A similar FtsZ localization pattern has been observed in cells with a disruption of the noc gene, which is required for nucleoid occlusion in B. subtilis (Wu & Errington, 2004
).
FtsZE300K protein (ftsZ6) formed diffuse broad FtsZ structures, but in contrast to FtsZS271R (ftsZ11), these structures tended to be located between nucleoids (arrowheads in Fig. 3R, S). Most of the FtsZE300K (ftsZ6) structures are probably non-functional, as the strain forms elongated filaments, with only occasional cells of normal length.
Effects of the ftsZ mutations in various division-mutant backgrounds
The range of phenotypes exhibited by the collection of ftsZ mutants suggested that they might be affected in different aspects of FtsZ function, or interactions with other components of the division machinery. We reasoned that we might get more information by combining the ftsZ mutations with mutations in other division genes. Therefore, we attempted to introduce each of the new ftsZ mutations into strains bearing mutations in various division genes (ezrA, ftsA279, minC, minD, noc and zapA), none of which seriously affects growth under normal conditions, and look for additional effects on the phenotype.
Most of the ftsZ mutations (ftsZ3, ftsZ4, ftsZ8, ftsZ11, ftsZ20, ftsZ24 and ftsZ38) had either only a weak or no additional phenotype when combined with any of the division mutations tested (data not shown). Two mutations, ftsZ5 and ftsZ6 (producing FtsZD174N and FtsZE300K, respectively), had lethal or near-lethal effects in most or all of the mutant backgrounds. The ftsZ6 mutation had the most severe effect, and double-mutant progeny were recovered at greatly reduced frequency in combination with mutations in ezrA, minD, minC and ftsA279. The mutation was viable in combination with zapA or noc mutation, but the colonies were small. Therefore, production of FtsZE300K (ftsZ6) mutant protein makes cells sensitive to a range of perturbations of the division machinery that are normally well tolerated. FtsZD174N (ftsZ5) mutant protein caused a similar, but less severe, effect. The ftsZ5 double mutants were generally viable, but the cells grew into long filaments, and sporulation was abolished. Absence of EzrA had the strongest effect, and double mutants could not be recovered at all.
Mutations ftsZ24 and ftsZ38 affect sporulation
Next we examined whether any of the ftsZ mutations that had approximately normal cell length, and produced FtsZ rings similar to those of the wild-type, had an effect on asymmetric cell division during sporulation, as measured by activation of the sporulation-specific -factor,
F (Feucht et al., 1999
; King et al., 1999
). Liquid cultures of various mutant strains were induced to sporulate, and
-galactosidase activity was measured from a lacZ fusion to the
F-dependent reporter gene spoIIQ. The ftsZ3 and ftsZ4 mutant strains (producing FtsZV260A and FtsZA285T, respectively) had a similar level of
F activity as an isogenic ftsZ+ strain (data not shown). As shown in Fig. 4
(A), an ftsZ24 mutant (producing FtsZI245F) exhibited slightly higher
-galactosidase activity than the wild-type. In contrast, the ftsZ38 mutant strain (producing FtsZL302P-Q353R) showed a drastically reduced
-galactosidase activity. These data were in good agreement with the darker and paler colour development seen on X-Gal plates by the ftsZ24 and ftsZ38 mutant strains, respectively. Interestingly, around 60 % of cells of strain 1368 (ftsZ38) appeared to have reached or gone beyond the stage of asymmetric septum completion 120 min after induction of sporulation (as judged by the formation of condensed prespore nucleoids; 64 % in the equivalent ftsZ+ strain), suggesting that the reduced activation of
F is not due to a block in formation of the asymmetric septum. To determine which of the two substitutions in the original ftsZ38 mutant was responsible for the impairment of sporulation, each mutation was reconstructed in the vector plasmid (pSG1928) using site-directed mutagenesis, and the mutations were introduced separately into strain 1272. Fig. 4(B)
shows that the strain containing the mutation generating the Q353R (ftsZ38-2) substitution sporulated like the wild-type on plates grown at 37 °C, whereas the L302P (ftsZ38-1) substitution produced a defect in sporulation like that of the original double mutant. During the course of this work, we also observed that the ftsZ38 mutant strain was temperature sensitive. Colonies grown at room temperature were indistinguishable for sporulation from the wild-type, whereas a defect in sporulation was detected when the strain was grown at 37 or 48 °C (Fig. 4B
and data not shown). Preliminary results showed that the mean length of vegetative cells was not affected at higher growth temperatures, suggesting that the FtsZL302P-Q353R protein (ftsZ38) is specifically affected in sporulation (Fig. 1G, H
and data not shown).
|
![]() |
DISCUSSION |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
|
Bi & Lutkenhaus (1992) described the isolation of a temperature-sensitive ftsZ26 mutant in E. coli that forms FtsZ spirals, and leads to the formation of spirally invaginated septa (Addinall & Lutkenhaus, 1996
). The mutant turned out to have an insertion of six additional amino acids between amino acids 38 and 39 of FtsZ. Interestingly, the ftsZ20 mutant strain, which exhibits a similar phenotype to the ftsZ26 mutant (Figs 1 and 3
), carries a single valine to alanine substitution at position 38. These data strongly support the notion that the shape of the FtsZ ring dictates the pattern of septal ingrowth (Addinall & Lutkenhaus, 1996
), and it appears that residue V38 is directly involved in determining the direction of polymerization, and, when altered, leads to the formation of FtsZ spirals, and thus to twisted cells. The fact that several mutant proteins, and especially FtsZS271R (ftsZ11), formed FtsZ spirals, but no twisted cells were detected, suggests that the mutant FtsZ spirals seen by IFM differed in their ability to direct the shape of the invaginating septum. Alternatively, the shape of the FtsZ ring might not be enough to determine the shape of the invaginating septum.
Stricker & Erickson (2003) isolated ftsZ mutations in E. coli that formed extensive spirals, but were not capable of cell division. Production of the FtsZS271R (ftsZ11) mutant protein caused a similar phenotype, but here the mutant FtsZ is partially functional, as normal and filamentous cells were observed (Figs 1 and 3
). It seems that long spirals extending over the nucleoid are formed in B. subtilis under various conditions, e.g. in a noc mutant strain, or in cells undergoing sporulation where formation of a spiral-like filament is an intermediate step of the switch from medial to polar FtsZ position (Ben-Yehuda & Losick, 2002
; Wu & Errington, 2004
).
Interestingly, a number of mutant proteins [FtsZV260A (ftsZ3), FtsZA285T (ftsZ4) and FtsZI245F (ftsZ24)] caused the formation of a significant amount of DNA-free minicells (Fig. 1, Table 2
). The approximately normal cell length, and the ability to form discrete linear FtsZ bands similar to those of the wild-type (Figs 3
), imply that the mutated FtsZs retained their normal assembly and constriction function. The formation of minicells suggests that these mutant proteins are less sensitive to the destabilizing action of MinC. The mutations probably do not abolish binding to MinC completely, as the amounts of minicells are not as high as in a min mutant strain (Marston et al., 1998
). Alternatively, the mutant proteins might form more stable polymers, and thereby be more resistant to the action of MinC. It is interesting that all three mutated residues are located quite close together on the FtsZ protein (Fig. 5
). Bi & Lutkenhaus (1990)
isolated SulA-resistant ftsZ mutants in E. coli that also formed increased levels of minicells, but the mutations lie at different sites compared with the above-mentioned B. subtilis ftsZ mutations.
The ftsZ38 mutant (producing FtsZL302P-Q353R mutant protein) differed from all of the others in being drastically affected in sporulation and activation of F (Fig. 4
), even though preliminary light microscopy experiments suggested that medial and asymmetric division are near normal. Previously, an ftsA mutant with aberrant asymmetric septa, but no defect in vegetative growth, has been described (Kemp et al., 2002
; Young, 1976
), suggesting that FtsA protein has a distinct or additional role in asymmetric septation compared with vegetative division. The phenotype of the ftsZ38 mutation suggests that FtsZ may also have a modified role in asymmetric septation, either directly or indirectly via FtsA. Alternatively, the FtsZL302P-Q353R mutant protein may be affected in binding, and thereby localizing the sporulation-specific division protein SpoIIE (Lucet et al., 2000
).
In conclusion, B. subtilis appears to be a good organism in which to create and study mutations in the essential ftsZ gene. The easy integration of the ftsZ alleles into the chromosome, and thus disruption of the wild-type copy of ftsZ, allows the viability and morphological phenotype of the mutants to be examined directly. Screening the mutant library for efficient sporulation (as an indication for changes in vegetative and/or asymmetric division) seemed to be quite sensitive, as we were able to isolate mutations with a range of mild phenotypes. Large-scale characterization of ftsZ mutants by this approach may help to shed light on the crucial questions of the role of FtsZ in assembly and constriction of the division machinery, and its coupling with cell growth, chromosome replication and segregation.
![]() |
ACKNOWLEDGEMENTS |
---|
![]() |
REFERENCES |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Anagnostopoulos, C. & Spizizen, C. (1961). Requirements for transformation in Bacillus subtilis. J Bacteriol 81, 741746.
Barak, I. & Youngman, P. (1996). SpoIIE mutants of Bacillus subtilis comprise two distinct phenotypic classes consistent with a dual functional role for the SpoIIE protein. J Bacteriol 178, 49844989.
Beall, B. & Lutkenhaus, J. (1992). Impaired cell division and sporulation of a Bacillus subtilis strain with the ftsA gene deleted. J Bacteriol 174, 23982403.[Abstract]
Beall, B., Lowe, M. & Lutkenhaus, J. (1988). Cloning and characterization of Bacillus subtilis homologs of Escherichia coli cell division genes ftsZ and ftsA. J Bacteriol 170, 48554864.[Medline]
Ben-Yehuda, S. & Losick, R. (2002). Asymmetric cell division in B. subtilis involves a spiral-like intermediate of the cytokinetic protein FtsZ. Cell 109, 257266.[CrossRef][Medline]
Bi, E. & Lutkenhaus, J. (1990). Analysis of ftsZ mutations that confer resistance to the cell division inhibitor SulA (SfiA). J Bacteriol 172, 56025609.[Medline]
Bi, E. & Lutkenhaus, J. (1992). Isolation and characterization of ftsZ alleles that affect septal morphology. J Bacteriol 174, 54145423.[Abstract]
Bramhill, D. & Thompson, C. M. (1994). GTP-dependent polymerization of Escherichia coli FtsZ protein to form tubules. Proc Natl Acad Sci U S A 91, 58135817.
Daniel, R. A. & Errington, J. (2000). Intrinsic instability of the essential cell division protein FtsL of Bacillus subtilis and a role for DivIB protein in FtsL turnover. Mol Microbiol 36, 278289.[CrossRef][Medline]
Daniel, R. A., Harry, E. J. & Errington, J. (2000). Role of penicillin-binding protein PBP 2B in assembly and functioning of the division machinery of Bacillus subtilis. Mol Microbiol 35, 299311.[CrossRef][Medline]
Erickson, H. P., Taylor, D. W., Taylor, K. A. & Bramhill, D. (1996). Bacterial cell division protein FtsZ assembles into protofilament sheets and minirings, structural homologs of tubulin polymers. Proc Natl Acad Sci U S A 93, 519523.
Errington, J. (1984). Efficient Bacillus subtilis cloning system using bacteriophage vector 105J9. J Gen Microbiol 130, 26152628.[Medline]
Errington, J. (2003). Regulation of endospore formation in Bacillus subtilis. Nat Rev Microbiol 1, 117126.[CrossRef][Medline]
Errington, J. & Mandelstam, J. (1986). Use of a lacZ gene fusion to determine the dependence pattern of sporulation operon spoIIA in spo mutants of Bacillus subtilis. J Gen Microbiol 132, 29672976.[Medline]
Errington, J., Daniel, R. A. & Scheffers, D. J. (2003). Cytokinesis in bacteria. Microbiol Mol Biol Rev 67, 5265.
Feucht, A., Magnin, T., Yudkin, M. D. & Errington, J. (1996). Bifunctional protein required for asymmetric cell division and cell-specific transcription in Bacillus subtilis. Genes Dev 10, 794803.[Abstract]
Feucht, A., Daniel, R. A. & Errington, J. (1999). Characterization of a morphological checkpoint coupling cell-specific transcription to septation in Bacillus subtilis. Mol Microbiol 33, 10151026.[CrossRef][Medline]
Feucht, A., Lucet, I., Yudkin, M. D. & Errington, J. (2001). Cytological and biochemical characterization of the FtsA cell division protein of Bacillus subtilis. Mol Microbiol 40, 115125.[CrossRef][Medline]
Feucht, A., Abbotts, L. & Errington, J. (2002). The cell differentiation protein SpoIIE contains a regulatory site that controls its phosphatase activity in response to asymmetric septation. Mol Microbiol 45, 11191130.[CrossRef][Medline]
Gueiros-Filho, F. J. & Losick, R. (2002). A widely conserved bacterial cell division protein that promotes assembly of the tubulin-like protein FtsZ. Genes Dev 16, 25442556.
Haeusser, D. P., Schwartz, R. L., Smith, A. M., Oates, M. E. & Levin, P. A. (2004). EzrA prevents aberrant cell division by modulating assembly of the cytoskeletal protein FtsZ. Mol Microbiol 52, 801814.[CrossRef][Medline]
Jenkinson, H. F. (1983). Altered arrangement of proteins in the spore coat of a germination mutant of Bacillus subtilis. J Gen Microbiol 129, 19451958.[Medline]
Katis, V. L., Wake, R. G. & Harry, E. J. (2000). Septal localization of the membrane-bound division proteins of Bacillus subtilis DivIB and DivIC is codependent only at high temperatures and requires FtsZ. J Bacteriol 182, 36073611.
Kemp, J. T., Driks, A. & Losick, R. (2002). FtsA mutants of Bacillus subtilis impaired in sporulation. J Bacteriol 184, 38563863.
Khvorova, A., Zhang, L., Higgins, M. L. & Piggot, P. J. (1998). The spoIIE locus is involved in the Spo0A-dependent switch in the location of FtsZ rings in Bacillus subtilis. J Bacteriol 180, 12561260.
King, N., Dreesen, O., Stragier, P., Pogliano, K. & Losick, R. (1999). Septation, dephosphorylation, and the activation of F during sporulation in Bacillus subtilis. Genes Dev 13, 11561167.
Levin, P. A., Shim, J. J. & Grossman, A. D. (1998). Effect of minCD on FtsZ ring position and polar septation in Bacillus subtilis. J Bacteriol 180, 60486051.
Lewis, P. J. & Errington, J. (1996). Use of green fluorescent protein for detection of cell-specific gene expression and subcellular protein localization during sporulation in Bacillus subtilis. Microbiology 142, 733740.[Medline]
Low, H. H., Moncrieffe, M. C. & Lowe, J. (2004). The crystal structure of ZapA and its modulation of FtsZ polymerization. J Mol Biol 341, 839852.[CrossRef][Medline]
Lowe, J. & Amos, L. A. (1998). Crystal structure of the bacterial cell-division protein FtsZ. Nature 391, 203206.[CrossRef][Medline]
Lowe, J. & Amos, L. A. (1999). Tubulin-like protofilaments in Ca2+-induced FtsZ sheets. EMBO J 18, 23642371.
Lucet, I., Feucht, A., Yudkin, M. D. & Errington, J. (2000). Direct interaction between the cell division protein FtsZ and the cell differentiation protein SpoIIE. EMBO J 19, 14671475.
Ma, X. & Margolin, W. (1999). Genetic and functional analyses of the conserved C-terminal core domain of Escherichia coli FtsZ. J Bacteriol 181, 75317544.
Marston, A. L. & Errington, J. (1999). Selection of the midcell division site in Bacillus subtilis through MinD-dependent polar localization and activation of MinC. Mol Microbiol 33, 8496.[CrossRef][Medline]
Marston, A. L., Thomaides, H. B., Edwards, D. H., Sharpe, M. E. & Errington, J. (1998). Polar localization of the MinD protein of Bacillus subtilis and its role in selection of the mid-cell division site. Genes Dev 12, 34193430.
Meissner, P. S., Sisk, W. P. & Berman, M. L. (1987). Bacteriophage cloning system for the construction of directional cDNA libraries. Proc Natl Acad Sci U S A 84, 41714175.
Mosyak, L., Zhang, Y., Glasfeld, E., Haney, S., Stahl, M., Seehra, J. & Somers, W. S. (2000). The bacterial cell-division protein ZipA and its interaction with an FtsZ fragment revealed by X-ray crystallography. EMBO J 19, 31793191.
Mukherjee, A. & Lutkenhaus, J. (1994). Guanine nucleotide-dependent assembly of FtsZ into filaments. J Bacteriol 176, 27542758.[Abstract]
Mukherjee, A. & Lutkenhaus, J. (1998). Dynamic assembly of FtsZ regulated by GTP hydrolysis. EMBO J 17, 462469.
Nogales, E., Wolf, S. G. & Downing, K. H. (1998). Structure of the tubulin dimer by electron crystallography. Nature 391, 199203.[CrossRef][Medline]
Palacios, P., Vicente, M. & Sanchez, M. (1996). Dependency of Escherichia coli cell-division size, and independency of nucleoid segregation on the mode and level of ftsZ expression. Mol Microbiol 20, 10931098.[Medline]
Partridge, S. R. & Errington, J. (1993). The importance of morphological events and intercellular interactions in the regulation of prespore-specific gene expression during sporulation in Bacillus subtilis. Mol Microbiol 8, 945955.[Medline]
Pogliano, K., Harry, E. & Losick, R. (1995). Visualization of the subcellular location of sporulation proteins in Bacillus subtilis using immunofluorescence microscopy. Mol Microbiol 18, 459470.[CrossRef][Medline]
Resnekov, O., Alper, S. & Losick, R. (1996). Subcellular localization of proteins governing the proteolytic activation of a developmental transcription factor in Bacillus subtilis. Genes Cells 1, 529542.
Romberg, L. & Levin, P. A. (2003). Assembly dynamics of the bacterial cell division protein FtsZ: poised at the edge of stability. Annu Rev Microbiol 57, 125154.[CrossRef][Medline]
Sambrook, J., Fritsch, E. F. & Maniatis, T. (1989). Molecular Cloning: a Laboratory Manual, 2nd edn. Cold Spring Harbor, NY: Cold Spring Harbor Laboratory.
Scheffers, D. J., de Wit, J. G., den Blaauwen, T. & Driessen, A. J. (2002). GTP hydrolysis of cell division protein FtsZ: evidence that the active site is formed by the association of monomers. Biochemistry 41, 521529.[CrossRef][Medline]
Sharpe, M. E., Hauser, P. M., Sharpe, R. G. & Errington, J. (1998). Bacillus subtilis cell cycle as studied by fluorescence microscopy: constancy of cell length at initiation of DNA replication and evidence for active nucleoid partitioning. J Bacteriol 180, 547555.
Sievers, J., Raether, B., Perego, M. & Errington, J. (2002). Characterization of the parB-like yyaA gene of Bacillus subtilis. J Bacteriol 184, 11021111.
Sterlini, J. M. & Mandelstam, J. (1969). Commitment to sporulation in Bacillus subtilis and its relationship to development of actinomycin resistance. Biochem J 113, 2937.[Medline]
Stevens, C. M., Daniel, R., Illing, N. & Errington, J. (1992). Characterization of a sporulation gene, spoIVA, involved in spore coat morphogenesis in Bacillus subtilis. J Bacteriol 174, 586594.[Abstract]
Stricker, J. & Erickson, H. P. (2003). In vivo characterization of Escherichia coli ftsZ mutants: effects on Z-ring structure and function. J Bacteriol 185, 47964805.
Thomaides, H. B., Freeman, M., El Karoui, M. & Errington, J. (2001). Division site selection protein DivIVA of Bacillus subtilis has a second distinct function in chromosome segregation during sporulation. Genes Dev 15, 16621673.
Vaughan, S., Wickstead, B., Gull, K. & Addinall, S. G. (2004). Molecular evolution of FtsZ protein sequences encoded within the genomes of archaea, bacteria, and eukaryota. J Mol Evol 58, 1929.[CrossRef][Medline]
Wang, X., Huang, J., Mukherjee, A., Cao, C. & Lutkenhaus, J. (1997). Analysis of the interaction of FtsZ with itself, GTP, and FtsA. J Bacteriol 179, 55515559.
Ward, J. E., Jr & Lutkenhaus, J. (1985). Overproduction of FtsZ induces minicell formation in E. coli. Cell 42, 941949.[CrossRef][Medline]
Weart, R. B. & Levin, P. A. (2003). Growth rate-dependent regulation of medial FtsZ ring formation. J Bacteriol 185, 28262834.
Wu, L. J. & Errington, J. (2004). Coordination of cell division and chromosome segregation by a nucleoid occlusion protein in Bacillus subtilis. Cell 117, 915925.[CrossRef][Medline]
Young, M. (1976). Use of temperature-sensitive mutants to study gene expression during sporulation in Bacillus subtilis. J Bacteriol 126, 928936.[Medline]
Yu, X. C. & Margolin, W. (1997). Ca2+-mediated GTP-dependent dynamic assembly of bacterial cell division protein FtsZ into asters and polymer networks in vitro. EMBO J 16, 54555463.
Received 18 January 2005;
revised 8 March 2005;
accepted 10 March 2005.
HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
INT J SYST EVOL MICROBIOL | MICROBIOLOGY | J GEN VIROL |
J MED MICROBIOL | ALL SGM JOURNALS |