scholarly journals Specificity and selective advantage of an exclusion system in the integrative and conjugative element ICEBs1 of Bacillus subtilis

2021 ◽  
Author(s):  
Kathleen P. Davis ◽  
Alan D. Grossman
Keyword(s):  
Bacillus Subtilis ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Cell Envelope ◽  
Donor Cell ◽  
High Specificity ◽  
Host Cells ◽  
Cell Contact ◽  
Bacterial Evolution ◽  
Potential Donor

AbstractIntegrative and conjugative elements (ICEs) are mobile genetic elements capable of transferring their own and other DNA. They contribute to the spread of antibiotic resistances and other important traits for bacterial evolution. Exclusion is a mechanism used by many conjugative plasmids and a few ICEs to prevent their host cell from acquiring a second copy of the cognate element. ICEBs1 of Bacillus subtilis has an exclusion mechanism whereby the exclusion protein YddJ in a potential recipient inhibits the activity of the ICEBs1-encoded conjugation machinery in a potential donor. The target of YddJ-mediated exclusion is the conjugation protein ConG (a VirB6 homolog). Here we defined the regions of YddJ and ConG that confer exclusion specificity and determined the importance of exclusion to host cells. Using chimeras that had parts of ConG from ICEBs1 and the closely related ICEBat1 we identified a putative extracellular loop of ConG that conferred specificity for exclusion by the cognate YddJ. Using chimeras of YddJ from ICEBs1 and ICEBat1 we identified two regions in YddJ needed for exclusion specificity. We also found that YddJ-mediated exclusion reduced death of donor cells following conjugation into recipients. Donor death was dependent on the ability of transconjugants to themselves become donors and was reduced under osmo-protective conditions, indicating that death was likely due to alterations in the donor cell envelope caused by excessive conjugation. We postulate that elements that can have high frequencies of transfer likely evolved exclusion mechanisms to protect the host cells from excessive death.ImportanceHorizontal gene transfer is a driving force in bacterial evolution, responsible for the spread of many traits, including antibiotic and heavy metal resistances. Conjugation, one type of horizontal gene transfer, involves DNA transfer from donor to recipient cells through conjugation machinery and direct cell-cell contact. Exclusion mechanisms allow conjugative elements to prevent their host from acquiring additional copies of the element, and are highly specific enabling hosts to acquire heterologous elements. We defined regions of the exclusion protein and its target in the conjugation machinery that convey high specificity of exclusion. We found that exclusion protects donors from cell death during periods of high transfer. This is likely important for the element to enter new populations of cells.

scholarly journals Specificity and Selective Advantage of an Exclusion System in the Integrative and Conjugative Element ICEBs1 of Bacillus subtilis

2021 ◽  
Vol 203 (10) ◽  
Author(s):  
Kathleen P. Davis ◽  
Alan D. Grossman
Keyword(s):  
Bacillus Subtilis ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Donor Cell ◽  
Metal Resistance ◽  
Host Cells ◽  
Cell Contact ◽  
Bacterial Evolution ◽  
Potential Donor ◽  
Content Type

ABSTRACT Integrative and conjugative elements (ICEs) are mobile genetic elements capable of transferring their own and other DNA. They contribute to the spread of antibiotic resistance and other important traits for bacterial evolution. Exclusion is a mechanism used by many conjugative plasmids and a few ICEs to prevent their host cell from acquiring a second copy of the cognate element. ICEBs1 of Bacillus subtilis has an exclusion mechanism whereby the exclusion protein YddJ in a potential recipient inhibits the activity of the ICEBs1-encoded conjugation machinery in a potential donor. The target of YddJ-mediated exclusion is the conjugation protein ConG (a VirB6 homolog). Here, we defined the regions of YddJ and ConG that confer exclusion specificity and determined the importance of exclusion to host cells. Using chimeras that had parts of ConG from ICEBs1 and the closely related ICEBat1, we identified a putative extracellular loop of ConG that conferred specificity for exclusion by the cognate YddJ. Using chimeras of YddJ from ICEBs1 and ICEBat1, we identified two regions in YddJ needed for exclusion specificity. We also found that YddJ-mediated exclusion reduced the death of donor cells following conjugation into recipients. Donor death was dependent on the ability of transconjugants to themselves become donors and was reduced under osmoprotective conditions, indicating that death was likely due to alterations in the donor cell envelope caused by excessive conjugation. We postulate that elements that can have high frequencies of transfer likely evolved exclusion mechanisms to protect the host cells from excessive death. IMPORTANCE Horizontal gene transfer is a driving force in bacterial evolution, responsible for the spread of many traits, including antibiotic and heavy metal resistance. Conjugation, one type of horizontal gene transfer, involves DNA transfer from donor to recipient cells through conjugation machinery and direct cell-cell contact. Exclusion mechanisms allow conjugative elements to prevent their host from acquiring additional copies of the element and are highly specific, enabling hosts to acquire heterologous elements. We defined regions of the exclusion protein and its target in the conjugation machinery that convey high specificity of exclusion. We found that exclusion protects donors from cell death during periods of high transfer. This is likely important for the element to enter new populations of cells.

scholarly journals The Composition of the Cell Envelope Affects Conjugation in Bacillus subtilis

2016 ◽  
Vol 198 (8) ◽  
pp. 1241-1249 ◽  
Author(s):  
Christopher M. Johnson ◽  
Alan D. Grossman
Keyword(s):  
Bacillus Subtilis ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Cell Envelope ◽  
Microbial Evolution ◽  
Major Type ◽  
Content Type ◽  
New Genes ◽  
Mutant Cells ◽  
Integrative And Conjugative Element

ABSTRACTConjugation in bacteria is the contact-dependent transfer of DNA from one cell to another via donor-encoded conjugation machinery. It is a major type of horizontal gene transfer between bacteria. Conjugation of the integrative and conjugative element ICEBs1intoBacillus subtilisis affected by the composition of phospholipids in the cell membranes of the donor and recipient. We found that reduction (or elimination) of lysyl-phosphatidylglycerol caused by loss ofmprFcaused a decrease in conjugation efficiency. Conversely, alterations that caused an increase in lysyl-phosphatidylglycerol, including loss ofugtPor overproduction ofmprF, caused an increase in conjugation efficiency. In addition, we found that mutations that alter production of other phospholipids, e.g., loss ofclsAandyfnI, also affected conjugation, apparently without substantively altering levels of lysyl-phosphatidylglycerol, indicating that there are multiple pathways by which changes to the cell envelope affect conjugation. We found that the contribution ofmprFto conjugation was affected by the chemical environment. Wild-type cells were generally more responsive to addition of anions that enhanced conjugation, whereasmprFmutant cells were more sensitive to combinations of anions that inhibited conjugation at pH 7. Our results indicate thatmprFand lysyl-phosphatidylglycerol allow cells to maintain relatively consistent conjugation efficiencies under a variety of ionic conditions.IMPORTANCEHorizontal gene transfer is a driving force in microbial evolution, enabling cells that receive DNA to acquire new genes and phenotypes. Conjugation, the contact-dependent transfer of DNA from a donor to a recipient by a donor-encoded secretion machine, is a prevalent type of horizontal gene transfer. Although critically important, it is not well understood how the recipient influences the success of conjugation. We found that the composition of phospholipids in the membranes of donors and recipients influences the success of transfer of the integrative and conjugative element ICEBs1inBacillus subtilis. Specifically, the presence of lysyl-phosphatidylglycerol enables relatively constant conjugation efficiencies in a range of diverse chemical environments.

scholarly journals Selfish, promiscuous, and sometimes useful: how mobile genetic elements drive horizontal gene transfer in microbial populations

2021 ◽  
Author(s):  
Eduardo P. C. Rocha ◽  
Matthieu Haudiquet ◽  
Jorge Moura de Sousa ◽  
Marie Touchon
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Cell Envelope ◽  
Horizontal Transmission ◽  
Donor Cell ◽  
Mobile Genetic Elements ◽  
Microbial Populations ◽  
Genetic Elements ◽  
Transfer Mechanisms ◽  
Host Genes

Horizontal gene transfer (HGT) drives microbial adaptation but is often under the control of mobile genetic elements (MGEs) whose interests are not necessarily aligned with those of their hosts. In general, transfer is costly to the donor cell while potentially beneficial to the recipients. The diversity and plasticity of cell-MGEs interactions, and those among MGEs, results in complex evolutionary processes where the source, or even the existence of selection for maintaining a function in the genome is often unclear. For example, MGE-driven HGT depends on cell envelope structures and defense systems, but many of these are transferred by MGEs themselves. MGEs can spur periods of intense gene transfer by increasing their own rates of horizontal transmission upon communicating, eavesdropping, or sensing the environment and the host physiology. This may result on high-frequency transfer of host genes unrelated with the MGE. Here, we review how MGEs drive HGT and how their transfer mechanisms, selective pressures, and genomic traits affect gene flow, and therefore adaptation, in microbial populations. The encoding of many adaptive niche-defining microbial traits in MGEs means that intragenomic conflicts and alliances between cells and their MGEs are key to microbial functional diversification.

scholarly journals Kin discrimination promotes horizontal gene transfer between unrelated strains in Bacillus subtilis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Polonca Stefanic ◽  
Katarina Belcijan ◽  
Barbara Kraigher ◽  
Rok Kostanjšek ◽  
Joseph Nesme ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Social Interactions ◽  
Recipient Strain ◽  
Donor Strain ◽  
Kin Discrimination ◽  
Defence Mechanisms ◽  
Donor Cells ◽  
Novel Alleles

AbstractBacillus subtilis is a soil bacterium that is competent for natural transformation. Genetically distinct B. subtilis swarms form a boundary upon encounter, resulting in killing of one of the strains. This process is mediated by a fast-evolving kin discrimination (KD) system consisting of cellular attack and defence mechanisms. Here, we show that these swarm antagonisms promote transformation-mediated horizontal gene transfer between strains of low relatedness. Gene transfer between interacting non-kin strains is largely unidirectional, from killed cells of the donor strain to surviving cells of the recipient strain. It is associated with activation of a stress response mediated by sigma factor SigW in the donor cells, and induction of competence in the recipient strain. More closely related strains, which in theory would experience more efficient recombination due to increased sequence homology, do not upregulate transformation upon encounter. This result indicates that social interactions can override mechanistic barriers to horizontal gene transfer. We hypothesize that KD-mediated competence in response to the encounter of distinct neighbouring strains could maximize the probability of efficient incorporation of novel alleles and genes that have proved to function in a genomically and ecologically similar context.

scholarly journals Involvement of plastid, mitochondrial and nuclear genomes in plant-to-plant horizontal gene transfer

2014 ◽  
Vol 83 (4) ◽  
pp. 317-323 ◽  
Author(s):  
Maria Virginia Sanchez-Puerta
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Plant Mitochondria ◽  
Genetic Material ◽  
Single Copy ◽  
Convincing Evidence ◽  
Cell Contact ◽  
Plant Mtdna ◽  
Nuclear Genomes ◽  
Foreign Genes

This review focuses on plant-to-plant horizontal gene transfer (HGT) involving the three DNA-containing cellular compartments. It highlights the great incidence of HGT in the mitochondrial genome (mtDNA) of angiosperms, the increasing number of examples in plant nuclear genomes, and the lack of any convincing evidence for HGT in the well-studied plastid genome of land plants. Most of the foreign mitochondrial genes are non-functional, generally found as pseudogenes in the recipient plant mtDNA that maintains its functional native genes. The few exceptions involve chimeric HGT, in which foreign and native copies recombine leading to a functional and single copy of the gene. Maintenance of foreign genes in plant mitochondria is probably the result of genetic drift, but a possible evolutionary advantage may be conferred through the generation of genetic diversity by gene conversion between native and foreign copies. Conversely, a few cases of nuclear HGT in plants involve functional transfers of novel genes that resulted in adaptive evolution. Direct cell-to-cell contact between plants (e.g. host-parasite relationships or natural grafting) facilitate the exchange of genetic material, in which HGT has been reported for both nuclear and mitochondrial genomes, and in the form of genomic DNA, instead of RNA. A thorough review of the literature indicates that HGT in mitochondrial and nuclear genomes of angiosperms is much more frequent than previously expected and that the evolutionary impact and mechanisms underlying plant-to-plant HGT remain to be uncovered.

scholarly journals Trasposon Mediated Horizontal Gene Transfer (T-HGT) of Circulating Tumor DNA Reshapes MM Clonal Architecture

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3065-3065
Author(s):  
Munevver Cinar ◽  
Steven Flygare ◽  
Marina Mosunjac ◽  
Ganji Nagaraju ◽  
Dongkyoo Park ◽  
...  
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Drug Sensitivity ◽  
Genetic Material ◽  
Host Cells ◽  
Response To Treatment ◽  
Hierarchical Architecture ◽  
Tumor Evolution ◽  
Sequencing Analysis

Spatial genetic heterogeneity is a characteristic phenomenon that influences multiple myeloma's (MM) phenotype and drug sensitivity (Rasche L. et al and Bolli N et al.). Hence, the branch model of tumor evolution is not sufficient to explain the disorganized architecture observed in MM. In this study, we investigated whether MM ctDNA horizontal gene transfer (HGT) affect tumor genetic architecture and drug sensitivity, resembling what is seen in prokaryotes, and elucidated the mechanisms involved in the mobilization of genetic material from one cell to another. We identified that plasma from patients with MM transmits drug sensitivity or resistance to cells in culture. This transmission of drug sensitivity is mediated by ctDNA transfer of oncogenes to a host cell. Importantly, in vitro and in vivo demonstrated that ctDNA mainly targets cells resembling the cell of origin (tropism). Karyotype spreads and whole genome sequencing demonstrated that once patients ctDNA encounters host cells, it migrates into the nucleus where it ultimately integrates into the cell's genome. Integration to the genome was confirmed to be targeted to myeloma cells. Further sequencing analysis of multiple MM samples identified ctDNA tropism and integration is dependent on the 5' and 3' end presence of transposable elements (TE), particularly of the MIR and ALUsq family. These results were further validated by TE mediated delivery of GFP into MM cells in vitro and HSVTK in tumors of mouse xenografts. In conclusion, this data indicates for the first time that TE mediates MM ctDNA HGT into homologous tumor cells shaping the hierarchical architecture of tumor clones and affecting tumor response to treatment. Therapeutically, this unique quality of ctDNA can be exploited for targeted gene therapeutic approaches in MM and potentially other cancers. Disclosures Bernal-Mizrachi: Kodikas Therapeutic Solutions, Inc: Equity Ownership; TAKEDA: Research Funding; Winship Cancer Institute: Employment, Patents & Royalties.

scholarly journals A mobile genetic element increases bacterial host fitness by manipulating development

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Joshua M Jones ◽  
Ilana Grinberg ◽  
Avigdor Eldar ◽  
Alan D Grossman
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Mobile Genetic Elements ◽  
Selective Advantage ◽  
Host Cells ◽  
Bacterial Host ◽  
Host Fitness ◽  
Genetic Elements ◽  
Necessary And Sufficient ◽  
Integrative And Conjugative Element

Horizontal gene transfer is a major force in bacterial evolution. Mobile genetic elements are responsible for much of horizontal gene transfer and also carry beneficial cargo genes. Uncovering strategies used by mobile genetic elements to benefit host cells is crucial for understanding their stability and spread in populations. We describe a benefit that ICEBs1, an integrative and conjugative element of Bacillus subtilis, provides to its host cells. Activation of ICEBs1 conferred a frequency-dependent selective advantage to host cells during two different developmental processes: biofilm formation and sporulation. These benefits were due to inhibition of biofilm-associated gene expression and delayed sporulation by ICEBs1-containing cells, enabling them to exploit their neighbors and grow more prior to development. A single ICEBs1 gene, devI (formerly ydcO), was both necessary and sufficient for inhibition of development. Manipulation of host developmental programs allows ICEBs1 to increase host fitness, thereby increasing propagation of the element.

Prediction of horizontal gene transfers in eukaryotes: approaches and challenges

2009 ◽  
Vol 37 (4) ◽  
pp. 792-795 ◽  
Author(s):  
John W. Whitaker ◽  
Glenn A. McConkey ◽  
David R. Westhead
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Present Review ◽  
Bacterial Evolution ◽  
Eukaryotic Evolution ◽  
Metabolic Evolution ◽  
Eukaryotic Genomes

HGT (horizontal gene transfer) is recognized as an important force in bacterial evolution. Now that many eukaryotic genomes have been sequenced, it has become possible to carry out studies of HGT in eukaryotes. The present review compares the different approaches that exist for identifying HGT genes and assess them in the context of studying eukaryotic evolution. The metabolic evolution resource metaTIGER is then described, with discussion of its application in identification of HGT in eukaryotes.

Sign in / Sign up

Export Citation Format

Share Document