scholarly journals Streptomyces coelicolor Genes ftsL and divIC Play a Role in Cell Division but Are Dispensable for Colony Formation

2007 ◽  
Vol 189 (24) ◽  
pp. 8982-8992 ◽  
Author(s):  
Jennifer A. Bennett ◽  
Rachel M. Aimino ◽  
Joseph R. McCormick

ABSTRACT We have characterized homologues of the bacterial cell division genes ftsL and divIC in the gram-positive mycelial bacterium Streptomyces coelicolor A3(2). We show by deletion-insertion mutations that ftsL and divIC are dispensable for growth and viability in S. coelicolor. When mutant strains were grown on a conventional rich medium (R2YE, containing high sucrose), inactivation of either ftsL or divIC resulted in the formation of aerial hyphae with partially constricted division sites but no clear separation of prespore compartments. Surprisingly, this phenotype was largely suppressed when strains were grown on minimal medium or sucrose-free R2YE, where division sites in many aerial hyphae had finished constricting and chains of spores were evident. Thus, osmolarity appears to affect the severity of the division defect. Furthermore, double mutant strains deleted for both ftsL and divIC are viable and have medium-dependent phenotypes similar to that of the single mutant strains, suggesting that functions performed by FtsL and DivIC are not absolutely required for septation during growth and sporulation. Alternatively, another division protein may partially compensate for the loss of both FtsL and DivIC on minimal medium or sucrose-free R2YE. Finally, based on transmission electron microscopy observations, we propose that FtsL and DivIC are involved in coordinating symmetrical annular ingrowth of the invaginating septum.

Open Biology ◽  
2013 ◽  
Vol 3 (3) ◽  
pp. 130006 ◽  
Author(s):  
Bartosz Ditkowski ◽  
Neil Holmes ◽  
Joanna Rydzak ◽  
Magdalena Donczew ◽  
Martyna Bezulska ◽  
...  

Prior to bacterial cell division, the ATP-dependent polymerization of the cytoskeletal protein, ParA, positions the newly replicated origin-proximal region of the chromosome by interacting with ParB complexes assembled on parS sites located close to the origin. During the formation of unigenomic spores from multi-genomic aerial hyphae compartments of Streptomyces coelicolor , ParA is developmentally triggered to form filaments along the hyphae; this promotes the accurate and synchronized segregation of tens of chromosomes into prespore compartments. Here, we show that in addition to being a segregation protein, ParA also interacts with the polarity protein, Scy, which is a component of the tip-organizing centre that controls tip growth. Scy recruits ParA to the hyphal tips and regulates ParA polymerization. These results are supported by the phenotype of a strain with a mutant form of ParA that uncouples ParA polymerization from Scy. We suggest that the ParA–Scy interaction coordinates the transition from hyphal elongation to sporulation.


2014 ◽  
Vol 20 (2) ◽  
pp. 275-284 ◽  
Author(s):  
Charul Jani ◽  
Elitza I. Tocheva ◽  
Scott McAuley ◽  
Arryn Craney ◽  
Grant J. Jensen ◽  
...  

Cell division is essential for spore formation but not for viability in the filamentous streptomycetes bacteria. Failure to complete cell division instead blocks spore formation, a phenotype that can be visualized by the absence of gray (in Streptomyces coelicolor) and green (in Streptomyces venezuelae) spore-associated pigmentation. Despite the lack of essentiality, the streptomycetes divisome is similar to that of other prokaryotes. Therefore, the chemical inhibitors of sporulation in model streptomycetes may interfere with the cell division in rod-shaped bacteria as well. To test this, we investigated 196 compounds that inhibit sporulation in S. coelicolor. We show that 19 of these compounds cause filamentous growth in Bacillus subtilis, consistent with impaired cell division. One of the compounds is a DNA-damaging agent and inhibits cell division by activating the SOS response. The remaining 18 act independently of known stress responses and may therefore act on the divisome or on divisome positioning and stability. Three of the compounds (Fil-1, Fil-2, and Fil-3) confer distinct cell division defects on B. subtilis. They also block B. subtilis sporulation, which is mechanistically unrelated to the sporulation pathway of streptomycetes but is also dependent on the divisome. We discuss ways in which these differing phenotypes can be used in screens for cell division inhibitors.


2020 ◽  
Author(s):  
Le Zhang ◽  
Joost Willemse ◽  
Paula Yagüe ◽  
Ellen de Waal ◽  
Dennis Claessen ◽  
...  

ABSTRACTBacterial cytokinesis starts with the polymerization of the tubulin-like FtsZ, which forms the cell division scaffold. SepF aligns FtsZ polymers and also acts as a membrane anchor for the Z-ring. While in most bacteria cell division takes place at midcell, during sporulation of Streptomyces many septa are laid down almost simultaneously in multinucleoid aerial hyphae. The genomes of streptomycetes encode two additional SepF paralogs, SflA and SflB, which can interact with SepF. Here we show that the sporogenic aerial hyphae of sflA and sflB mutants of Streptomyces coelicolor frequently branch, a phenomenon never seen in the wild-type strain. The branching coincided with ectopic localization of DivIVA along the lateral wall of sporulating aerial hyphae. Constitutive expression of SflA and SflB largely inhibited hyphal growth, further correlating SflAB activity to that of DivIVA. SflAB localized in foci prior to and after the time of sporulation-specific cell division, while SepF co-localized with active septum synthesis. Foci of FtsZ and DivIVA frequently persisted between adjacent spores in spore chains of sflA and sflB mutants, at sites occupied by SflAB in wild-type cells. This may be caused by the persistance of SepF multimers in the absence of SflAB. Taken together, our data show that SflA and SflB play an important role in the control of growth and cell division during Streptomyces development.


2003 ◽  
Vol 185 (4) ◽  
pp. 1455-1458 ◽  
Author(s):  
Geertje van Keulen ◽  
Henk M. Jonkers ◽  
Dennis Claessen ◽  
Lubbert Dijkhuizen ◽  
Han A. B. Wösten

ABSTRACT Streptomyces coelicolor differentiates on solid agar media by forming aerial hyphae that septate into spores. We here show that differentiation also occurs in standing liquid minimal media. After a period of submerged growth, hyphae migrate to the air interface, where they become fixed by a rigid reflecting film. Colonies that result from these hyphae form sporulating aerial hyphae. In addition, submerged hyphae in the liquid minimal medium may attach to the surface. Liquid standing cultures easily become anoxic only 1 to 2 mm below the surface. Yet, biomass increases, implying the existence of metabolic pathways supporting anaerobic growth.


Genetics ◽  
1999 ◽  
Vol 151 (2) ◽  
pp. 569-584
Author(s):  
Justin R Nodwell ◽  
Melody Yang ◽  
David Kuo ◽  
Richard Losick

Abstract Morphogenesis in the bacterium Streptomyces coelicolor involves the formation of a lawn of hair-like aerial hyphae on the colony surface that stands up in the air and differentiates into chains of spores. bld mutants are defective in the formation of this aerial mycelium and grow as smooth, hairless colonies. When certain pairs of bld mutants are grown close to one another on rich sporulation medium, they exhibit extracellular complementation such that one mutant restores aerial mycelium formation to the other. The extracellular complementation relationships of most of the previously isolated bld mutants placed them in a hierarchy of extracellular complementation groups. We have screened for further bld mutants with precautions intended to maximize the discovery of additional genes. Most of the 50 newly isolated mutant strains occupy one of three of the previously described positions in the hierarchy, behaving like bldK, bldC, or bldD mutants. We show that the mutations in some of the strains that behave like bldK are bldK alleles but that others fall in a cluster at a position on the chromosome distinct from that of any known bld gene. We name this locus bldL. By introducing cloned genes into the strains that exhibit bldC or bldD-like extracellular complementation phenotypes, we show that most of these strains are likely to contain mutations in genes other than bldC or bldD. These results indicate that the genetic control of aerial mycelium formation is more complex than previously recognized and support the idea that a high proportion of bld genes are directly or indirectly involved in the production of substances that are exchanged between cells during morphological differentiation.


2006 ◽  
Vol 188 (4) ◽  
pp. 1540-1550 ◽  
Author(s):  
Ricardo Del Sol ◽  
Jonathan G. L. Mullins ◽  
Nina Grantcharova ◽  
Klas Flärdh ◽  
Paul Dyson

ABSTRACT The product of the crgA gene of Streptomyces coelicolor represents a novel family of small proteins. A single orthologous gene is located close to the origin of replication of all fully sequenced actinomycete genomes and borders a conserved gene cluster implicated in cell growth and division. In S. coelicolor, CrgA is important for coordinating growth and cell division in sporogenic hyphae. In this study, we demonstrate that CrgA is an integral membrane protein whose peak expression is coordinated with the onset of development of aerial hyphae. The protein localizes to discrete foci away from growing hyphal tips. Upon overexpression, CrgA localizes to apical syncytial cells of aerial hyphae and inhibits the formation of productive cytokinetic rings of the bacterial tubulin homolog FtsZ, leading to proteolytic turnover of this major cell division determinant. In the absence of known prokaryotic cell division inhibitors in actinomycetes, CrgA may have an important conserved function influencing Z-ring formation in these bacteria.


2020 ◽  
Author(s):  
Apichaya Traithan ◽  
Pongsri Tongtawe ◽  
Jeeraphong Thanongsaksrikul ◽  
Supayang Voravuthikunchai ◽  
Potjanee Sriman

Abstract Rhodomyrtone has been recently demonstrated to possess a novel antibiotic mechanism of action against Gram-positive bacteria which involves multiple targets, resulting in the interference of several bacterial biological processes including cell division. The present study aims to closely look at the downstream effect of rhodomyrtone treatment on nucleoid segregation in Streptococcus suis, an important zoonotic pathogen. Minimum inhibition concentration (MIC) and minimum bactericidal concentration (MBC) values of rhodomyrtone against recombinant S. suis ParB-GFP, a nucleoid segregation reporter strain, were 0.5 and 1 µg/ml, respectively, equivalent to the potency of vancomycin. Using fluorescence live-cell imaging, we demonstrated that rhodomyrtone at 2 × MIC caused incomplete nucleoid segregation and septum misplacement, leading to the generation of anucleated cells. FtsZ immune-staining of rhodomyrtone-treated S. suis for 30 min revealed that although large amount of FtsZ was trapped in the region of high fluidity membrane, it appeared to be able to polymerize to form a complete Z-ring. However, the Z-ring was shifted away from midcell. Transmission electron micrograph further confirmed disruption of nucleoid segregation and septum misplacement at 120 min following rhodomyrtone treatment. Asymmetric septum formation resulted in either generation of minicells without nucleoid, septum formed over incomplete segregated nucleoid (guillotine effect), or formation of multi-constriction of Z-ring within a single cell. This finding spotlights on antibacterial mechanism of rhodomyrtone involves the early stage in bacterial cell division process.


2020 ◽  
Author(s):  
Apichaya Traithan ◽  
Pongsri Tongtawe ◽  
Jeeraphong Thanongsaksrikul ◽  
Supayang Voravuthikunchai ◽  
Potjanee Sriman

Abstract Rhodomyrtone has been recently demonstrated to possess a novel antibiotic mechanism of action against Gram-positive bacteria which involved the multiple targets, resulting in the interference of several bacterial biological processes including the cell division. The present study aims to closely look at the downstream effect of rhodomyrtone treatment on nucleoid segregation in Streptococcus suis, an important zoonotic pathogen. The minimum inhibition concentration (MIC) and the minimum bactericidal concentration (MBC) values of rhodomyrtone against the recombinant S. suis ParB-GFP, a nucleoid segregation reporter strain, were 0.5 and 1 µg/ml, respectively, which were equivalent to the potency of vancomycin. Using the fluorescence live-cell imaging, we demonstrated that rhodomyrtone at 2 × MIC caused incomplete nucleoid segregation and septum misplacement, leading to the generation of anucleated cells. FtsZ immune-staining of rhodomyrtone-treated S. suis for 30 min revealed that the large amount of FtsZ was trapped in the region of high fluidity membrane and appeared to be able to polymerize to form a complete Z-ring. However, the Z-ring was shifted away from the midcell. Transmission electron microscopy further confirmed the disruption of nucleoid segregation and septum misplacement at 120 min following the rhodomyrtone treatment. Asymmetric septum formation resulted in either generation of minicells without nucleoid, septum formed over incomplete segregated nucleoid (guillotine effect), or formation of multi-constriction of Z-ring within a single cell. This finding spotlights on antibacterial mechanism of rhodomyrtone involves the early stage in bacterial cell division process.


2000 ◽  
Vol 182 (20) ◽  
pp. 5653-5662 ◽  
Author(s):  
Gilles P. van Wezel ◽  
Jannes van der Meulen ◽  
Shinichi Kawamoto ◽  
Ruud G. M. Luiten ◽  
Henk K. Koerten ◽  
...  

ABSTRACT The role of ssgA in cell division and development of streptomycetes was analyzed. An ssgA null mutant ofStreptomyces coelicolor produced aerial hyphae but failed to sporulate, and ssgA can therefore be regarded as a novelwhi gene. In addition to the morphological changes, antibiotic production was also disturbed, with strongly reduced actinorhodin production. These defects could be complemented by plasmid-borne ssgA. In the wild-type strain, transcription of ssgA was induced by nutritional shift-down and was shown to be linked to that of the upstream-located gene ssgR, which belongs to the family of iclR-type transcriptional regulator genes. Analysis of mycelium harvested from liquid-grown cultures by transmission electron microscopy showed that septum formation had strongly increased in ssgA-overexpressing strains in comparison to wild-type S. coelicolor and that spore-like compartments were produced at high frequency. Furthermore, the hyphae were significantly wider and contained irregular and often extremely thick septa. These data underline the important role forssgA in Streptomyces cell division.


Open Biology ◽  
2016 ◽  
Vol 6 (4) ◽  
pp. 150164 ◽  
Author(s):  
Le Zhang ◽  
Joost Willemse ◽  
Dennis Claessen ◽  
Gilles P. van Wezel

Bacterial cell division is a highly complex process that requires tight coordination between septum formation and chromosome replication and segregation. In bacteria that divide by binary fission a single septum is formed at mid-cell, a process that is coordinated by the conserved cell division scaffold protein FtsZ. In contrast, during sporulation-specific cell division in streptomycetes, up to a hundred rings of FtsZ (Z rings) are produced almost simultaneously, dividing the multinucleoid aerial hyphae into long chains of unigenomic spores. This involves the active recruitment of FtsZ by the SsgB protein, and at the same time requires sophisticated systems to regulate chromosome dynamics. Here, we show that SepG is required for the onset of sporulation and acts by ensuring that SsgB is localized to future septum sites. Förster resonance energy transfer imaging suggests direct interaction between SepG and SsgB. The beta-lactamase reporter system showed that SepG is a transmembrane protein with its central domain oriented towards the cytoplasm. Without SepG, SsgB fails to localize properly, consistent with a crucial role for SepG in the membrane localization of the SsgB–FtsZ complex. While SsgB remains associated with FtsZ, SepG re-localizes to the (pre)spore periphery. Expanded doughnut-shaped nucleoids are formed in sepG null mutants, suggesting that SepG is required for nucleoid compaction. Taken together, our work shows that SepG, encoded by one of the last genes in the conserved dcw cluster of cell division and cell-wall-related genes in Gram-positive bacteria whose function was still largely unresolved , coordinates septum synthesis and chromosome organization in Streptomyces .


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