Role of the Single-Stranded DNA–Binding Protein SsbB in Pneumococcal Transformation: Maintenance of a Reservoir for Genetic Plasticity

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Bacteria encode a single-stranded DNA (ssDNA) binding protein (SSB) crucial for genome maintenance. In Bacillus subtilis and Streptococcus pneumoniae, an alternative SSB, SsbB, is expressed uniquely during competence for genetic transformation, but its precise role has been disappointingly obscure. Here, we report our investigations involving comparison of a null mutant (ssbB⁻) and a C-ter truncation (ssbBΔ7) of SsbB of S. pneumoniae, the latter constructed because SSBs' acidic tail has emerged as a key site for interactions with partner proteins. We provide evidence that SsbB directly protects internalized ssDNA. We show that SsbB is highly abundant, potentially allowing the binding of ∼1.15 Mb ssDNA (half a genome equivalent); that it participates in the processing of ssDNA into recombinants; and that, at high DNA concentration, it is of crucial importance for chromosomal transformation whilst antagonizing plasmid transformation. While the latter observation explains a long-standing observation that plasmid transformation is very inefficient in S. pneumoniae (compared to chromosomal transformation), the former supports our previous suggestion that SsbB creates a reservoir of ssDNA, allowing successive recombination cycles. SsbBΔ7 fulfils the reservoir function, suggesting that SsbB C-ter is not necessary for processing protein(s) to access stored ssDNA. We propose that the evolutionary raison d'être of SsbB and its abundance is maintenance of this reservoir, which contributes to the genetic plasticity of S. pneumoniae by increasing the likelihood of multiple transformation events in the same cell.

Vyšlo v časopise: Role of the Single-Stranded DNA–Binding Protein SsbB in Pneumococcal Transformation: Maintenance of a Reservoir for Genetic Plasticity. PLoS Genet 7(6): e32767. doi:10.1371/journal.pgen.1002156
Kategorie: Research Article
prolekare.web.journal.doi_sk: https://doi.org/10.1371/journal.pgen.1002156

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1. HillerNLAhmedAPowellEMartinDPEutseyR 2010 Generation of genic diversity among Streptococcus pneumoniae strains via horizontal gene transfer during a chronic polyclonal pediatric infection. PLoS Pathog 6 e1001108 doi:10.1371/journal.ppat.1001108

2. CroucherNJHarrisSRFraserCQuailMABurtonJ 2011 Rapid pneumococcal evolution in response to clinical interventions. Science 331 430 434

3. LacksSGreenbergBCarlsonK 1967 Fate of donor DNA in pneumococcal transformation. J Mol Biol 29 327 347

4. DagkessamanskaiaAMoscosoMHénardVGuiralSOverwegK 2004 Interconnection of competence, stress and CiaR regulons in Streptococcus pneumoniae: competence triggers stationary phase autolysis of ciaR mutant cells. Mol Microbiol 51 1071 1086

5. PetersonSSungCKClineRDesaiBVSnesrudE 2004 Identification of competence pheromone responsive genes in Streptococcus pneumoniae. Mol Microbiol 51 1051 1070

6. HåvarsteinLSCoomaraswamyGMorrisonDA 1995 An unmodified heptadecapeptide pheromone induces competence for genetic transformation in Streptococcus pneumoniae. Proc Natl Acad Sci USA 92 11140 11144

7. ClaverysJPHåvarsteinLS 2002 Extra-cellular peptide control of competence for genetic transformation in Streptococcus pneumoniae. Frontiers in Biosci 7 1798 1814

8. ClaverysJPPrudhommeMMartinB 2006 Induction of competence regulons as general stress responses in Gram-positive bacteria. Annu Rev Microbiol 60 451 475

9. Ephrussi-TaylorH 1960 L'état du DNA transformant au cours des premières phases de la transformation bactérienne. C R Soc Biol 154 1951 1955

10. MiaoRGuildWR 1970 Competent Diplococcus pneumoniae accept both single- and double-stranded deoxyribonucleic acid. J Bacteriol 101 361 364

11. MorrisonDAMannarelliB 1979 Transformation in pneumococcus: nuclease resistance of deoxyribonucleic acid in eclipse complex. J Bacteriol 140 655 665

12. MorrisonDA 1977 Transformation in pneumococcus: existence and properties of a complex involving donor deoxyribonucleate single strands in eclipse. J Bacteriol 132 576 583

13. MorrisonDABakerM 1979 Competence for genetic transformation in pneumococcus depends on synthesis of a small set of proteins. Nature 282 215 217

14. MorrisonDABakerMMannarelliB 1979 GloverSWButlerLO Transformation - 1978 43 52 Cotswold Press Ltd, Oxford, U.K

15. MorrisonDAMortier-BarrièreIAttaiechLClaverysJP 2007 Identification of the Major Protein Component of the Pneumococcal Eclipse Complex. J Bacteriol 189 6497 6500

16. ClaverysJPMartinBPolardP 2009 The genetic transformation machinery: composition, localization and mechanism. FEMS Microbiol Rev 33 643 656

17. ThanassiJAHartman-NeumannSLDoughertyTJDoughertyBAPucciMJ 2002 Identification of 113 conserved essential genes using a high-throughput gene disruption system in Streptococcus pneumoniae. Nucleic Acids Res 30 3152 3162

18. CampbellEAChoiSYMasureHR 1998 A competence regulon in Streptococcus pneumoniae revealed by genomic analysis. Mol Microbiol 27 929 939

19. BergéMMortier-BarrièreIMartinBClaverysJP 2003 Transformation of Streptococcus pneumoniae relies on DprA- and RecA-dependent protection of incoming single strands. Mol Microbiol 50 527 536

20. Mortier-BarrièreIVeltenMDupaignePMirouzeNPiétrementO 2007 A key presynaptic role in transformation for a widespread bacterial protein: DprA conveys incoming ssDNA to RecA. Cell 130 824 836

21. BerkaRMHahnJAlbanoMDraskovicIPersuhM 2002 Microarray analysis of the Bacillus subtilis K-state: genome-wide expression changes dependent on ComK. Mol Microbiol 43 1331 1345

22. OguraMYamaguchiHKobayashiKOgasawaraNFujitaY 2002 Whole-genome analysis of genes regulated by the Bacillus subtilis competence transcription factor ComK. J Bacteriol 184 2344 2351

23. LindnerCNijlandRvan HartskampMBronSHamoenL 2004 Differential expression of two paralogous genes of Bacillus subtilis encoding single-stranded DNA binding protein. J Bacteriol 186 1097 1105

24. GroveDEBryantFR 2006 Effect of Mg2+ on the DNA binding modes of the Streptococcus pneumoniae SsbA and SsbB proteins. J Biol Chem 281 2087 2094

25. SheredaRDKozlovAGLohmanTMCoxMMKeckJL 2008 SSB as an organizer/mobilizer of genome maintenance complexes. Crit Rev Biochem Mol Biol 43 289 318

26. CostesALecointeFMcGovernSQuevillon-CheruelSPolardP 2010 The C-Terminal Domain of the Bacterial SSB Protein Acts as a DNA Maintenance Hub at Active Chromosome Replication Forks. PLoS Genet 6 e1001238 doi:10.1371/journal.pgen.1001238

27. MéjeanVClaverysJP 1984 Use of a cloned fragment to analyze the fate of donor DNA in transformation of Streptococcus pneumoniae. J Bacteriol 158 1175 1178

28. SaundersCWGuildWR 1981 Pathway of plasmid transformation in pneumococcus: open circular and linear molecules are active. J Bacteriol 146 517 526

29. MorrisonDAGuildWR 1973 Breakage prior to entry of DNA in Pneumococcus transformation. Biochim Biophys Acta 299 545 556

30. ClaverysJPHåvarsteinLS 2007 Cannibalism and fratricide: mechanisms and raisons d'être. Nat Rev Microbiol 5 219 229

31. ClaverysJPMartinBHåvarsteinLS 2007 Competence-induced fratricide in streptococci. Mol Microbiol 64 1423 1433

32. BernsteinHByerlyHCHopfFAMichodRE 1985 The evolutionary role of recombinational repair and sex. Int Rev Cytol 96 1 24

33. DubnauD 1999 DNA uptake in bacteria. Annu Rev Microbiol 53 217 244

34. GroveDEWillcoxSGriffithJDBryantFR 2005 Differential single-stranded DNA binding properties of the paralogous SsbA and SsbB proteins from Streptococcus pneumoniae. J Biol Chem 280 11067 11073

35. SaundersCWGuildWR 1981 Monomer plasmid DNA transforms Streptococcus pneumoniae. Mol Gen Genet 181 57 62

36. KantakeNMadirajuMVSugiyamaTKowalczykowskiSC 2002 Escherichia coli RecO protein anneals ssDNA complexed with its cognate ssDNA-binding protein: A common step in genetic recombination. Proc Natl Acad Sci USA 99 15327 15332

37. KidaneDCarrascoBManfrediCRothmaierKAyoraS 2009 Evidence for different pathways during horizontal gene transfer in competent Bacillus subtilis cells. PLoS Genet 5 e1000630 doi:10.1371/journal.pgen.1000630

38. SiboldCMarkiewiczZLatorreCHakenbeckR 1991 Novel plasmids in clinical strains of Streptococcus pneumoniae. FEMS Microbiol Lett 77 91 96

39. PozziGMasalaLIannelliFManganelliRHåvarsteinLS 1996 Competence for genetic transformation in Streptococcus pneumoniae: two allelic variants of the peptide pheromone. J Bacteriol 178 6087 6090

40. SaundersCWGuildWR 1980 Properties and transforming activities of two plasmids in Streptococcus pneumoniae. Mol Gen Genet 180 573 578

41. SérénaC 2005 Etude moléculaire de la protéine SSB de Bacillus subtilis. Ph D Dissertation, Université Paris XI, Orsay, France

42. PrudhommeMCamilliAClaverysJP 2007 HakenbeckRChhatwalGS The Molecular Biology of Streptococci 511 518 Horizon Scientific Press, Norfolk, UK

43. CarteeRTForseeWTBenderMHAmbroseKDYotherJ 2005 CpsE from type 2 Streptococcus pneumoniae catalyzes the reversible addition of glucose-1-phosphate to a polyprenyl phosphate acceptor, initiating type 2 capsule repeat unit formation. J Bacteriol 187 7425 7433

44. LanieJANgWLKazmierczakKMAndrzejewskiTMDavidsenTM 2007 Genome Sequence of Avery's Virulent Serotype 2 Strain D39 of Streptococcus pneumoniae and Comparison with That of Unencapsulated Laboratory Strain R6. J Bacteriol 189 38 51

45. MartinBPrudhommeMAlloingGGranadelCClaverysJP 2000 Cross-regulation of competence pheromone production and export in the early control of transformation in Streptococcus pneumoniae. Mol Microbiol 38 867 878

46. BergéMMoscosoMPrudhommeMMartinBClaverysJP 2002 Uptake of transforming DNA in Gram-positive bacteria: a view from Streptococcus pneumoniae. Mol Microbiol 45 411 421