scholarly journals Essential dynamic interdependence of FtsZ and SepF for Z-ring and septum formation in Corynebacterium glutamicum

2019 ◽  
Author(s):  
Adrià Sogues ◽  
Mariano Martinez ◽  
Quentin Gaday ◽  
Mathilde Ben-Assaya ◽  
Martin Graña ◽  
...  
Keyword(s):  
Corynebacterium Glutamicum ◽  
Lipid Membranes ◽  
Cell Biology ◽  
Model Organism ◽  
Binding Pocket ◽  
Model Organisms ◽  
Bacterial Phyla ◽  
Division Site ◽  
Ring Assembly ◽  
Z Ring

The mechanisms of Z-ring assembly and regulation in bacteria are poorly understood, particularly in non-model organisms. Actinobacteria, one of the largest bacterial phyla that includes the deadly human pathogen Mycobacterium tuberculosis, lack the canonical FtsZ-membrane anchors as well as all positive and negative Z-ring regulators described for E. coli. Here we investigate the physiological function of Corynebacterium glutamicum SepF, the only cell division-associated protein from Actinobacteria known to directly interact with the conserved C-terminal tail of FtsZ but whose actual mode of action in cytokinesis is yet to be elucidated. We used a mechanistic cell biology approach to unveil the essential interdependence of FtsZ and SepF required for the formation of a functional Z-ring in the actinobacterial model organism C. glutamicum. The crystal structure of the SepF-FtsZ complex reveals a hydrophobic FtsZ-binding pocket, which defines the SepF homodimer as the functional unit, and a reversible oligomerization interface regulated via an alpha helical switch. FtsZ filaments and lipid membranes have opposing effects on SepF polymerization, leading to a complex dynamic role of the protein at the division site, involving FtsZ bundling, Z-ring tethering and membrane reshaping activities that are needed for proper Z-ring assembly and function.

scholarly journals Cardiolipin-Containing Lipid Membranes Attract the Bacterial Cell Division Protein DivIVA

2021 ◽  
Vol 22 (15) ◽  
pp. 8350
Author(s):  
Naďa Labajová ◽  
Natalia Baranova ◽  
Miroslav Jurásek ◽  
Robert Vácha ◽  
Martin Loose ◽  
...  
Keyword(s):  
Cell Division ◽  
Lipid Bilayers ◽  
Bacterial Cell ◽  
Lipid Membranes ◽  
Model Organism ◽  
Active Role ◽  
Membrane Curvature ◽  
Bacterial Cell Division ◽  
Division Site ◽  
Clostridioides Difficile

DivIVA is a protein initially identified as a spatial regulator of cell division in the model organism Bacillus subtilis, but its homologues are present in many other Gram-positive bacteria, including Clostridia species. Besides its role as topological regulator of the Min system during bacterial cell division, DivIVA is involved in chromosome segregation during sporulation, genetic competence, and cell wall synthesis. DivIVA localizes to regions of high membrane curvature, such as the cell poles and cell division site, where it recruits distinct binding partners. Previously, it was suggested that negative curvature sensing is the main mechanism by which DivIVA binds to these specific regions. Here, we show that Clostridioides difficile DivIVA binds preferably to membranes containing negatively charged phospholipids, especially cardiolipin. Strikingly, we observed that upon binding, DivIVA modifies the lipid distribution and induces changes to lipid bilayers containing cardiolipin. Our observations indicate that DivIVA might play a more complex and so far unknown active role during the formation of the cell division septal membrane.

scholarly journals Effects of Perturbing Nucleoid Structure on Nucleoid Occlusion-Mediated Toporegulation of FtsZ Ring Assembly

2004 ◽  
Vol 186 (12) ◽  
pp. 3951-3959 ◽  
Author(s):  
Qin Sun ◽  
William Margolin
Keyword(s):  
Chromosome Segregation ◽  
Potential Role ◽  
Membrane Insertion ◽  
Translation Inhibition ◽  
Ftsz Ring ◽  
Division Site ◽  
Ring Assembly ◽  
Z Ring ◽  
Nucleoid Structure

ABSTRACT In Escherichia coli, assembly of the FtsZ ring (Z ring) at the cell division site is negatively regulated by the nucleoid in a phenomenon called nucleoid occlusion (NO). Previous studies have indicated that chromosome packing plays a role in NO, as mukB mutants grown in rich medium often exhibit FtsZ rings on top of diffuse, unsegregated nucleoids. To address the potential role of overall nucleoid structure on NO, we investigated the effects of disrupting chromosome structure on Z-ring positioning. We found that NO was mostly normal in cells with inactivated DNA gyrase or in mukB-null mutants lacking topA, although some suppression of NO was evident in the latter case. Previous reports suggesting that transcription, translation, and membrane insertion of proteins (“transertion”) influence nucleoid structure prompted us to investigate whether disruption of these activities had effects on NO. Blocking transcription caused nucleoids to become diffuse, and FtsZ relocalized to multiple bands on top of these nucleoids, biased towards midcell. This suggested that these diffuse nucleoids were defective in NO. Blocking translation with chloramphenicol caused characteristic nucleoid compaction, but FtsZ rarely assembled on top of these centrally positioned nucleoids. This suggested that NO remained active upon translation inhibition. Blocking protein secretion by thermoinduction of a secA(Ts) strain caused a chromosome segregation defect similar to that in parC mutants, and NO was active. Although indirect effects are certainly possible with these experiments, the above data suggest that optimum NO activity may require specific organization and structure of the nucleoid.

scholarly journals Using viromes to predict novel immune proteins in non-model organisms

2016 ◽  
Vol 283 (1837) ◽  
pp. 20161200 ◽  
Author(s):  
Steven D. Quistad ◽  
Yan Wei Lim ◽  
Genivaldo Gueiros Z. Silva ◽  
Craig E. Nelson ◽  
Andreas F. Haas ◽  
...  
Keyword(s):  
Cell Biology ◽  
Model Organism ◽  
Transgenic Animals ◽  
Model Organisms ◽  
Metagenomic Sequencing ◽  
Immune Systems ◽  
Viral Communities ◽  
Novel Method ◽  
Alternative Approaches

Immunity is mostly studied in a few model organisms, leaving the majority of immune systems on the planet unexplored. To characterize the immune systems of non-model organisms alternative approaches are required. Viruses manipulate host cell biology through the expression of proteins that modulate the immune response. We hypothesized that metagenomic sequencing of viral communities would be useful to identify both known and unknown host immune proteins. To test this hypothesis, a mock human virome was generated and compared to the human proteome using tBLASTn, resulting in 36 proteins known to be involved in immunity. This same pipeline was then applied to reef-building coral, a non-model organism that currently lacks traditional molecular tools like transgenic animals, gene-editing capabilities, and in vitro cell cultures. Viromes isolated from corals and compared with the predicted coral proteome resulted in 2503 coral proteins, including many proteins involved with pathogen sensing and apoptosis. There were also 159 coral proteins predicted to be involved with coral immunity but currently lacking any functional annotation. The pipeline described here provides a novel method to rapidly predict host immune components that can be applied to virtually any system with the potential to discover novel immune proteins.

scholarly journals Novel Chromosome Organization Pattern in Actinomycetales—Overlapping Replication Cycles Combined with Diploidy

mBio ◽  
2017 ◽  
Vol 8 (3) ◽  
Author(s):  
Kati Böhm ◽  
Fabian Meyer ◽  
Agata Rhomberg ◽  
Jörn Kalinowski ◽  
Catriona Donovan ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Dna Replication ◽  
Corynebacterium Glutamicum ◽  
Model Organism ◽  
Growth Conditions ◽  
Mycolic Acid ◽  
Model Organisms ◽  
Cell Cycles ◽  
Slow Growing

ABSTRACT Bacteria regulate chromosome replication and segregation tightly with cell division to ensure faithful segregation of DNA to daughter generations. The underlying mechanisms have been addressed in several model species. It became apparent that bacteria have evolved quite different strategies to regulate DNA segregation and chromosomal organization. We have investigated here how the actinobacterium Corynebacterium glutamicum organizes chromosome segregation and DNA replication. Unexpectedly, we found that C. glutamicum cells are at least diploid under all of the conditions tested and that these organisms have overlapping C periods during replication, with both origins initiating replication simultaneously. On the basis of experimental data, we propose growth rate-dependent cell cycle models for C. glutamicum. IMPORTANCE Bacterial cell cycles are known for few model organisms and can vary significantly between species. Here, we studied the cell cycle of Corynebacterium glutamicum, an emerging cell biological model organism for mycolic acid-containing bacteria, including mycobacteria. Our data suggest that C. glutamicum carries two pole-attached chromosomes that replicate with overlapping C periods, thus initiating a new round of DNA replication before the previous one is terminated. The newly replicated origins segregate to midcell positions, where cell division occurs between the two new origins. Even after long starvation or under extremely slow-growth conditions, C. glutamicum cells are at least diploid, likely as an adaptation to environmental stress that may cause DNA damage. The cell cycle of C. glutamicum combines features of slow-growing organisms, such as polar origin localization, and fast-growing organisms, such as overlapping C periods. IMPORTANCE Bacterial cell cycles are known for few model organisms and can vary significantly between species. Here, we studied the cell cycle of Corynebacterium glutamicum, an emerging cell biological model organism for mycolic acid-containing bacteria, including mycobacteria. Our data suggest that C. glutamicum carries two pole-attached chromosomes that replicate with overlapping C periods, thus initiating a new round of DNA replication before the previous one is terminated. The newly replicated origins segregate to midcell positions, where cell division occurs between the two new origins. Even after long starvation or under extremely slow-growth conditions, C. glutamicum cells are at least diploid, likely as an adaptation to environmental stress that may cause DNA damage. The cell cycle of C. glutamicum combines features of slow-growing organisms, such as polar origin localization, and fast-growing organisms, such as overlapping C periods.

scholarly journals Human organoids: a new dimension in cell biology

2019 ◽  
Vol 30 (10) ◽  
pp. 1129-1137 ◽  
Author(s):  
Ruth Lehmann ◽  
Connie M. Lee ◽  
Erika C. Shugart ◽  
Marta Benedetti ◽  
R. Alta Charo ◽  
...  
Keyword(s):  
Cell Biology ◽  
Complex Disease ◽  
Task Force ◽  
Model Organism ◽  
Model Organisms ◽  
New Model ◽  
Anatomy And Physiology ◽  
Patient Consent ◽  
American Society

Organoids derived from stem cells or tissues in culture can develop into structures that resemble the in vivo anatomy and physiology of intact organs. Human organoid cultures provide the potential to study human development and model disease processes with the same scrutiny and depth of analysis customary for research with nonhuman model organisms. Resembling the complexity of the actual tissue or organ, patient-derived human organoid studies may accelerate medical research, creating new opportunities for tissue engineering and regenerative medicine, generating knowledge and tools for preclinical studies, including drug development and testing. Biologists are drawn to this system as a new “model organism” to study complex disease phenotypes and genetic variability among individuals using patient-derived tissues. The American Society for Cell Biology convened a task force to report on the potential, challenges, and limitations for human organoid research. The task force suggests ways to ease the entry for new researchers into the field and how to facilitate broader use of this new model organism within the research community. This includes guidelines for reproducibility, culturing, sharing of patient materials, patient consent, training, and communication with the public.

scholarly journals Cell Division in Bacillus subtilis: FtsZ and FtsA Association Is Z-Ring Independent, and FtsA Is Required for Efficient Midcell Z-Ring Assembly

2005 ◽  
Vol 187 (18) ◽  
pp. 6536-6544 ◽  
Author(s):  
S. O. Jensen ◽  
L. S. Thompson ◽  
E. J. Harry
Keyword(s):  
Bacillus Subtilis ◽  
Cell Division ◽  
Ring Formation ◽  
Division Site ◽  
Ring Assembly ◽  
Synchronous Cell ◽  
Z Ring ◽  
Membrane Bound ◽  
Chemical Cross Linking

ABSTRACT The earliest stage in cell division in bacteria is the assembly of a Z ring at the division site at midcell. Other division proteins are also recruited to this site to orchestrate the septation process. FtsA is a cytosolic division protein that interacts directly with FtsZ. Its function remains unknown. It is generally believed that FtsA localization to the division site occurs immediately after Z-ring formation or concomitantly with it and that FtsA is responsible for recruiting the later-assembling membrane-bound division proteins to the division site. Here, we report the development of an in vivo chemical cross-linking assay to examine the association between FtsZ and FtsA in Bacillus subtilis cells. We subsequently use this assay in a synchronous cell cycle to show that these two proteins can interact prior to Z-ring formation. We further show that in a B. subtilis strain containing an ftsA deletion, FtsZ localized at regular intervals along the filament but the majority of Z rings were abnormal. FtsA in this organism is therefore critical for the efficient formation of functional Z rings. This is the first report of abnormal Z-ring formation resulting from the loss of a single septation protein. These results suggest that in this organism, and perhaps others, FtsA ensures recruitment of the membrane-bound division proteins by ensuring correct formation of the Z ring.

scholarly journals Cryo-EM structure of the MinCD copolymeric filament from Pseudomonas aeruginosa at 3.1 Å resolution

2019 ◽  
Author(s):  
Andrzej Szewczak-Harris ◽  
James Wagstaff ◽  
Jan Löwe
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Cell Division ◽  
Reaction Mechanism ◽  
Lipid Membranes ◽  
Bacterial Species ◽  
Diffusion Reaction ◽  
Division Site ◽  
Z Ring ◽  
Cell Division Protein ◽  
Polymeric Assemblies

AbstractPositioning of the division site in many bacterial species relies on the MinCDE system, which prevents the cytokinetic Z-ring from assembling anywhere but the mid-cell, through an oscillatory diffusion-reaction mechanism. MinD dimers bind to membranes and, via their partner MinC, inhibit the polymerisation of cell division protein FtsZ into the Z-ring. MinC and MinD form polymeric assemblies in solution and on cell membranes. Here, we report the high-resolution cryo-EM structure of the copolymeric filaments of Pseudomonas aeruginosa MinCD. The filaments consist of three protofilaments made of alternating MinC and MinD dimers. The MinCD protofilaments are almost completely straight and assemble as single protofilaments on lipid membranes, which we also visualised by cryo-EM.

scholarly journals Publisher Correction: Genetic tool development in marine protists: emerging model organisms for experimental cell biology

2020 ◽  
Vol 17 (5) ◽  
pp. 551-551
Author(s):  
Drahomíra Faktorová ◽  
R. Ellen R. Nisbet ◽  
José A. Fernández Robledo ◽  
Elena Casacuberta ◽  
Lisa Sudek ◽  
...  
Keyword(s):  
Cell Biology ◽  
Model Organisms ◽  
Tool Development ◽  
Experimental Cell ◽  
Genetic Tool ◽  
Marine Protists

scholarly journals In Search of Species-Specific SNPs in a Non-Model Animal (European Bison (Bison bonasus))—Comparison of De Novo and Reference-Based Integrated Pipeline of STACKS Using Genotyping-by-Sequencing (GBS) Data

Animals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2226
Author(s):  
Sazia Kunvar ◽  
Sylwia Czarnomska ◽  
Cino Pertoldi ◽  
Małgorzata Tokarska
Keyword(s):  
Reference Genome ◽  
De Novo ◽  
Bos Taurus ◽  
Model Organism ◽  
Genotyping By Sequencing ◽  
Model Organisms ◽  
European Bison ◽  
Model Animal ◽  
Pcr Duplicates ◽  
Species Specific

The European bison is a non-model organism; thus, most of its genetic and genomic analyses have been performed using cattle-specific resources, such as BovineSNP50 BeadChip or Illumina Bovine 800 K HD Bead Chip. The problem with non-specific tools is the potential loss of evolutionary diversified information (ascertainment bias) and species-specific markers. Here, we have used a genotyping-by-sequencing (GBS) approach for genotyping 256 samples from the European bison population in Bialowieza Forest (Poland) and performed an analysis using two integrated pipelines of the STACKS software: one is de novo (without reference genome) and the other is a reference pipeline (with reference genome). Moreover, we used a reference pipeline with two different genomes, i.e., Bos taurus and European bison. Genotyping by sequencing (GBS) is a useful tool for SNP genotyping in non-model organisms due to its cost effectiveness. Our results support GBS with a reference pipeline without PCR duplicates as a powerful approach for studying the population structure and genotyping data of non-model organisms. We found more polymorphic markers in the reference pipeline in comparison to the de novo pipeline. The decreased number of SNPs from the de novo pipeline could be due to the extremely low level of heterozygosity in European bison. It has been confirmed that all the de novo/Bos taurus and Bos taurus reference pipeline obtained SNPs were unique and not included in 800 K BovineHD BeadChip.

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