scholarly journals A programmed cell division delay preserves genome integrity during natural genetic transformation in Streptococcus pneumoniae

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Matthieu J. Bergé ◽  
Chryslène Mercy ◽  
Isabelle Mortier-Barrière ◽  
Michael S. VanNieuwenhze ◽  
Yves V. Brun ◽  
...  
Keyword(s):  
Cell Division ◽  
Streptococcus Pneumoniae ◽  
Genetic Transformation ◽  
Genome Integrity ◽  
Natural Genetic Transformation

scholarly journals Natural Genetic Transformation Generates a Population of Merodiploids in Streptococcus pneumoniae

PLoS Genetics ◽  
2013 ◽  
Vol 9 (9) ◽  
pp. e1003819 ◽  
Author(s):  
Calum Johnston ◽  
Stéphanie Caymaris ◽  
Aldert Zomer ◽  
Hester J. Bootsma ◽  
Marc Prudhomme ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Genetic Transformation ◽  
Natural Genetic Transformation

scholarly journals An Unstable Competence-Induced Protein, CoiA, Promotes Processing of Donor DNA after Uptake during Genetic Transformation in Streptococcus pneumoniae

2006 ◽  
Vol 188 (14) ◽  
pp. 5177-5186 ◽  
Author(s):  
Bhushan V. Desai ◽  
Donald A. Morrison
Keyword(s):  
Streptococcus Pneumoniae ◽  
Genetic Transformation ◽  
Transcriptional Activation ◽  
Response Regulator ◽  
Specific Response ◽  
Dna Uptake ◽  
Gram Positive Bacteria ◽  
Specific Alternative ◽  
Natural Genetic Transformation

ABSTRACT Natural genetic transformation in Streptococcus pneumoniae entails transcriptional activation of at least two sets of genes. One set of genes, activated by the competence-specific response regulator ComE, is involved in initiating competence, whereas a second set is activated by the competence-specific alternative sigma factor ComX and functions in DNA uptake and recombination. Here we report an initial characterization of CoiA, a ComX-dependent gene product that is induced during competence and is required for transformation. CoiA is widely conserved among gram-positive bacteria, and in streptococci, the entire coiA locus composed of four genes is conserved. By use of immunoblot assay, we show that, similar to its message, CoiA protein is transient, appearing at 10 min and largely disappearing by 30 min post-competence induction. Using complementation analysis, we establish that coiA is the only gene of this induced locus needed for transformability. We find no indication of CoiA having a role in regulating competence. Finally, using 32P- and 3H-labeled donor DNA, we demonstrate that a coiA mutant can internalize normal amounts of donor DNA compared to the wild-type strain but is unable to process it into viable transformants, suggesting a role for CoiA after DNA uptake, either in DNA processing or recombination.

scholarly journals Choline-Binding Protein D (CbpD) in Streptococcus pneumoniae Is Essential for Competence-Induced Cell Lysis

2005 ◽  
Vol 187 (13) ◽  
pp. 4338-4345 ◽  
Author(s):  
Louise Kausmally ◽  
Ola Johnsborg ◽  
Merete Lunde ◽  
Eivind Knutsen ◽  
Leiv Sigve Håvarstein
Keyword(s):  
Streptococcus Pneumoniae ◽  
Genetic Transformation ◽  
Binding Protein ◽  
Bacterial Species ◽  
Ectopic Expression ◽  
Cell Lysis ◽  
Extracellular Dna ◽  
Naked Dna ◽  
Dna Release ◽  
Natural Genetic Transformation

ABSTRACT Streptococcus pneumoniae is an important human pathogen that is able to take up naked DNA from the environment by a quorum-sensing-regulated process called natural genetic transformation. This property enables members of this bacterial species to efficiently acquire new properties that may increase their ability to survive and multiply in the human host. We have previously reported that induction of the competent state in a liquid culture of Streptococcus pneumoniae triggers lysis of a subfraction of the bacterial population resulting in release of DNA. We have also proposed that such competence-induced DNA release is an integral part of natural genetic transformation that has evolved to increase the efficiency of gene transfer between pneumococci. In the present work, we have further elucidated the mechanism behind competence-induced cell lysis by identifying a putative murein hydrolase, choline-binding protein D (CbpD), as a key component of this process. By using real-time PCR to estimate the amount of extracellular DNA in competent relative to noncompetent cultures, we were able to show that competence-induced cell lysis and DNA release are strongly attenuated in a cbpD mutant. Ectopic expression of CbpD in the presence or absence of other competence proteins revealed that CbpD is essentially unable to cause cell lysis on its own but depends on at least one additional protein expressed during competence.

scholarly journals The Opposing Functions of Protein Kinases and Phosphatases in Chromosome Bipolar Attachment

2019 ◽  
Vol 20 (24) ◽  
pp. 6182 ◽  
Author(s):  
Delaney Sherwin ◽  
Yanchang Wang
Keyword(s):  
Cell Division ◽  
Chromosome Segregation ◽  
Protein Phosphatase ◽  
Spindle Assembly Checkpoint ◽  
Model Organism ◽  
Eukaryotic Cells ◽  
Genome Integrity ◽  
Chromosome Missegregation ◽  
Spindle Poles ◽  
Mitosis And Meiosis

Accurate chromosome segregation during cell division is essential to maintain genome integrity in all eukaryotic cells, and chromosome missegregation leads to aneuploidy and therefore represents a hallmark of many cancers. Accurate segregation requires sister kinetochores to attach to microtubules emanating from opposite spindle poles, known as bipolar attachment or biorientation. Recent studies have uncovered several mechanisms critical to chromosome bipolar attachment. First, a mechanism exists to ensure that the conformation of sister centromeres is biased toward bipolar attachment. Second, the phosphorylation of some kinetochore proteins destabilizes kinetochore attachment to facilitate error correction, but a protein phosphatase reverses this phosphorylation. Moreover, the activity of the spindle assembly checkpoint is regulated by kinases and phosphatases at the kinetochore, and this checkpoint prevents anaphase entry in response to faulty kinetochore attachment. The fine-tuned kinase/phosphatase balance at kinetochores is crucial for faithful chromosome segregation during both mitosis and meiosis. Here, we discuss the function and regulation of protein phosphatases in the establishment of chromosome bipolar attachment with a focus on the model organism budding yeast.

scholarly journals Involvement of FtsE ATPase and FtsX Extracellular Loops 1 and 2 in FtsEX-PcsB Complex Function in Cell Division of Streptococcus pneumoniae D39

mBio ◽  
2013 ◽  
Vol 4 (4) ◽  
Author(s):  
Lok-To Sham ◽  
Katelyn R. Jensen ◽  
Kevin E. Bruce ◽  
Malcolm E. Winkler
Keyword(s):  
Signal Transduction ◽  
Amino Acids ◽  
Cell Division ◽  
Streptococcus Pneumoniae ◽  
Amino Acid ◽  
Stationary Phase ◽  
Coiled Coil ◽  
Extracellular Loop ◽  
Coiled Coil Domain ◽  
Loop Domain

ABSTRACT The FtsEX protein complex has recently been proposed to play a major role in coordinating peptidoglycan (PG) remodeling by hydrolases with the division of bacterial cells. According to this model, cytoplasmic FtsE ATPase interacts with the FtsZ divisome and FtsX integral membrane protein and powers allosteric activation of an extracellular hydrolase interacting with FtsX. In the major human respiratory pathogen Streptococcus pneumoniae (pneumococcus), a large extracellular-loop domain of FtsX (ECL1FtsX) is thought to interact with the coiled-coil domain of the PcsB protein, which likely functions as a PG amidase or endopeptidase required for normal cell division. This paper provides evidence for two key tenets of this model. First, we show that FtsE protein is essential, that depletion of FtsE phenocopies cell defects caused by depletion of FtsX or PcsB, and that changes of conserved amino acids in the FtsE ATPase active site are not tolerated. Second, we show that temperature-sensitive (Ts) pcsB mutations resulting in amino acid changes in the PcsB coiled-coil domain (CCPcsB) are suppressed by ftsX mutations resulting in amino acid changes in the distal part of ECL1FtsX or in a second, small extracellular-loop domain (ECL2FtsX). Some FtsX suppressors are allele specific for changes in CCPcsB, and no FtsX suppressors were found for amino acid changes in the catalytic PcsB CHAP domain (CHAPPcsB). These results strongly support roles for both ECL1FtsX and ECL2FtsX in signal transduction to the coiled-coil domain of PcsB. Finally, we found that pcsB CC(Ts) mutants (Ts mutants carrying mutations in the region of pcsB corresponding to the coiled-coil domain) unexpectedly exhibit delayed stationary-phase autolysis at a permissive growth temperature. IMPORTANCE Little is known about how FtsX interacts with cognate PG hydrolases in any bacterium, besides that ECL1FtsX domains somehow interact with coiled-coil domains. This work used powerful genetic approaches to implicate a specific region of pneumococcal ECL1FtsX and the small ECL2FtsX in the interaction with CCPcsB. These findings identify amino acids important for in vivo signal transduction between FtsX and PcsB for the first time. This paper also supports the central hypothesis that signal transduction between pneumococcal FtsX and PcsB is linked to ATP hydrolysis by essential FtsE, which couples PG hydrolysis to cell division. The classical genetic approaches used here can be applied to dissect interactions of other integral membrane proteins involved in PG biosynthesis. Finally, delayed autolysis of the pcsB CC(Ts) mutants suggests that the FtsEX-PcsB PG hydrolase may generate a signal in the PG necessary for activation of the major LytA autolysin as pneumococcal cells enter stationary phase.

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