Publikationsserver der Universitätsbibliothek Marburg

Titel:Chromosome arrangement and dynamics in the budding bacterium Hyphomonas neptunium
Autor:Jung, Alexandra
Weitere Beteiligte: Thanbichler, Martin (Prof. Dr.)
Veröffentlicht:2016
URI:https://archiv.ub.uni-marburg.de/diss/z2016/0496
DOI: https://doi.org/10.17192/z2016.0496
URN: urn:nbn:de:hebis:04-z2016-04966
DDC:570 Biowissenschaften, Biologie
Publikationsdatum:2016-09-07
Lizenz:https://rightsstatements.org/vocab/InC-NC/1.0/

Dokument

Schlagwörter:
Hyphomonas neptunium, ParABS, Prokaryoten, chromosome segregation, replisome

Summary:
Faithful chromosome replication and segregation are essential for every living cell and must be tightly coordinated with other cell cycle events such as cell division. Our knowledge about prokaryotic chromosome dynamics is based on studies of only a few model organisms that divide by binary fission and are mostly characterized by a rod-like morphology. To broaden our insight into bacterial chromosome segregation, our lab has recently started to analyze chromosome dynamics in the marine alphaproteobacterium Hyphomonas neptunium, which divides by budding at the tip of the stalk and uses its stalk as a reproductive structure. This mode of reproduction distinguishes H. neptunium from so far studied model organisms and renders it an exciting candidate for the study of chromosome dynamics, since the duplicated chromosome must transit the stalk to reach the newly generated daughter cell. Recent work has revealed that the H. neptunium chromosome is segregated in a unique two-step process. At first, one of the duplicated origins is segregated within the mother cell, possibly in a ParABS-dependent manner, and remains at the stalked mother cell pole until a visible bud has formed at the tip of the stalk. In a second step, it is then segregated through the stalk into the bud. Several lines of evidence suggest that the transport through the stalk is mediated by a novel, yet unidentified, segregation mechanism. Commonly, chromosome replication and segregation occur concomitantly in bacteria. However, this two-step segregation mechanism implies a temporal uncoupling of chromosome replication and segregation through the stalk, reminiscent of eukaryotic mitosis. In this work, we analyzed the role of the ParABS system in chromosome segregation of H. neptunium. The ParABS system was shown to be essential for cell viability and chromosome segregation. Impairment of ParA functioning leads to morphological alterations and incomplete origin segregation within the mother cell and, consequently, hampers chromosome segregation through the stalk. This shows that the ParABS system mediates origin segregation within the mother cell. It also implies that chromosome segregation within the mother cell and through the stalk are sequential processes. Furthermore, we analyzed the role of PopZ and SMC in H. neptunium, since these proteins were shown to be involved in chromosome segregation in other bacteria. PopZ localizes to the pole opposite the stalk in the newly generated bud and appears to play only a minor role in the positioning of the ParABS partitioning machinery. SMC seems to be essential in H. neptunium and shows a similar localization pattern as ParB. Determination of the location of seven genomic loci in new-born cells revealed that the chromosome shows a longitudinal arrangement with the origin located at the flagellated pole and the terminus at the opposite cell pole. The other loci are arranged between both cell poles in a linear order that correlates with their position on the genomic map. Moreover, analysis of chromosome dynamics indicates that the ParB/parS complex is the region to be segregated first within the mother cell and also through the stalk, emphasizing its central role in the segregation process. As mentioned above, the observed two-step chromosome segregation mechanism suggested a temporal uncoupling of chromosome replication and its segregation through the stalk. To investigate the coordination between these two processes in more detail, we followed replisome dynamics by fluorescence labeling of different replisome components. The replication machinery shows a dynamic localization within the mother cell: in cells that are most likely at the swarmer-to-stalked cell transition as well as in stalked cells, it assembles at the pole opposite the (future) stalk and moves, via midcell, close to the stalked cell pole, where it disassembles again. This localization pattern is consistent with the observed location of the origin and terminus region. Furthermore, the replisomes appear to track independently along the two chromosome arms. Co-localization of ParB (origin) and DnaN (replisome) revealed that a large part of the chromosome is replicated before its segregation through the stalk commences, indicating that these processes are partially temporally uncoupled. Collectively, these observations expand our insight into chromosome dynamics in H. neptunium and suggest that it combines previously described segregation mechanisms, such as the ParABS system, with a novel segregation mechanism that awaits discovery.

Zusammenfassung:
Korrekte Chromosomenreplikation und die akkurate Segregation des Chromosoms sind essentiell für alle lebenden Zellen und müssen gut mit anderen Prozessen des Zellzyklus, wie z.B. der Zellteilung, abgestimmt sein. Unser bisheriges Wissen über prokaryotische Chromosomendynamik basiert auf Studien einiger weniger Modellorganismen, welche sich durch binäre Teilung fortpflanzen und meist eine stäbchenförmige Morphologie besitzen. Um unser Wissen über bakterielle Chromosomensegregation zu erweitern, wurde vor kurzem in unserem Labor begonnen, die Chromosomendynamik im marinen Alphaproteobakterium Hyphomonas neptunium zu untersuchen. H. neptunium teilt sich durch Knospung an der Stielspitze und verwendet seinen Stiel als reproduktive Struktur. Diese Art der Teilung unterscheidet H. neptunium von den bisher untersuchten Modellorganismen und macht es zu einem interessanten Kandidaten für die Analyse der Chromosomendynamik in Bakterien, da das duplizierte Chromosom zunächst den Stiel durchqueren muss, um die neu gebildete Tochterzelle zu erreichen. Neueste Studien zeigen, dass die Chromosomensegregation in einem einzigartigen, zweistufigen Mechanismus abzulaufen scheint. Zunächst wird die duplizierte centromer-ähnliche Region innerhalb der Mutterzelle, möglicherweise durch einen ParABS-abhängigen Mechanismus, an deren gestielten Pol segregiert und verweilt dort, bis sich eine sichtbare Knospe an der Stielspitze gebildet hat. Anschließend wird die centromer-ähnliche Region in einem zweiten Schritt durch den Stiel in die Knospe transportiert. Verschiedene Anhaltspunkte deuten darauf hin, dass dieser zweite Segregationsschritt durch einen neuen, bisher unbekannten Mechanismus vermittelt wird. Chromosomenreplikation und -segregation finden in Bakterien gewöhnlich gleichzeitig statt. Der zweiteilige Segregationsmechanismus lässt allerdings darauf schließen, dass die Chromosomenreplikation und die Segregation durch den Stiel, ähnlich wie bei der eukaryotischen Mitose, zeitlich entkoppelt sind. In dieser Arbeit wurde die Rolle des ParABS-Systems in der Chromosomensegregation in H. neptunium genauer analysiert. Es konnte gezeigt werden, dass das ParABS-System essentiell für die Lebensfähigkeit der Zelle sowie für die Chromosomensegregation ist. Die Beeinträchtigung der Funktionalität von ParA führte zu einer Veränderung der Zellmorphologie sowie zu einer unvollständigen Segregation der centromer- ähnlichen Region innerhalb der Mutterzelle, was dazu führte, dass auch die Segregation durch den Stiel nicht mehr stattfand. Dies zeigt, dass das ParABS-System die Segregation der centromer-ähnlichen Region in der Mutterzelle vermittelt und dass es sich bei der Segregation innerhalb der Mutterzelle und durch den Stiel um sequenzielle Prozesse handelt. Weiterhin wurde die Rolle von PopZ und SMC in H. neptunium untersucht, da diese Proteine in anderen Bakterien eine zum Teil wichtige Rolle in der Chromosomensegregation spielen. PopZ lokalisiert in der entstehenden Knospe am Pol gegenüber des Stiels und es konnte gezeigt werden, dass es eine untergeordnete Rolle in der Positionierung der ParABSSegregationsmaschinerie spielt. SMC scheint essentiell in H. neptunium zu sein und zeigt ein ähnliches Lokalisationsmuster wie ParB (centromer-ähnliche Region). Die Analyse sieben verschiedener genomischer Loci in neugeborenen Zellen zeigte, dass das Chromosom entlang der Längsachse der Zelle ausgerichtet ist, wobei die centromer-ähnliche Region am flagellierten und die Terminusregion am gegenüberliegen Zellpol liegt. Die anderen Loci zeigen eine lineare Anordnung zwischen den Zellpolen, welche mit ihrer Position in der chromosomalen Sequenz korreliert. Weiterhin wurde gezeigt, dass der ParB/parS-Komplex als erstes innerhalb der Mutterzelle und anschließend durch den Stiel segregiert wird, was die zentrale Rolle des Komplexes im Segregationsprozess verdeutlicht. Wie bereits erwähnt, deutet der zweiteilige Segregationsmechanismus auf eine zeitliche Entkopplung von Chromosomenreplikation und -segregation durch den Stiel hin. Um die Koordination dieser Prozesse genauer zu untersuchen, wurden Fluoreszenzfusionen verschiedener Replisomkomponenten generiert und deren Lokalisationsmuster analysiert. Die Replikationsmaschinerie zeigte eine dynamische Lokalisation innerhalb der Mutterzelle: in Zellen, die sich sehr wahrscheinlich am Übergang vom Schwärmer- zum Stielzellstadium befinden, sowie in gestielten Zellen wird das Replisom am Pol gegenüber des (zukünftigen) Stiels assembliert und bewegt sich über die Zellmitte in die Nähe des gestielten Pols, wo es anschließend wieder deassembliert wird. Dieses Lokalisationsmuster korreliert mit der Lage der Ursprungs- und Terminusregion innerhalb der Zelle. Die beiden Replisomen scheinen unabhängig voneinander entlang der beiden Chromosomenarme zu wandern. Die Kolokalisation von ParB (centromer-ähnliche Region) und DnaN (Replisom) zeigte, dass häufig ein Großteil des Chromosoms bereits repliziert ist, bevor dessen Segregation durch den Stiel erfolgt. Dies bedeutet, dass die Replikation zum Teil zeitlich von der Segregation durch den Stiel entkoppelt ist. Zusammenfassend erweitern diese Beobachtungen unseren Einblick in die Chromosomendynamik in H. neptunium und deuten darauf hin, dass dieser Organismus bereits beschriebene Segregationsmechanismen, wie das ParABS-System, mit einem neuartigen Mechanismus kombiniert, den es aufzuklären gilt.

Bibliographie / References

  1. 245. Chen JC, Viollier PH, Shapiro L. 2005. A membrane metalloprotease participates in the sequential degradation of a Caulobacter polarity determinant. Mol Microbiol 55:1085-1103.
  2. 249. Eisheuer S. 2011. Analyse der Zellteilung in Hyphomonas neptunium. Master Thesis. PhilippsUniversität Marburg.
  3. 218. Jensen RB. 2006. Analysis of the terminus region of the Caulobacter crescentus chromosome and identification of the dif site. J Bacteriol 188:6016-6019.
  4. 241. Huang L. 2011. A new mechanistic growth model for simultaneous determination of lag phase duration and exponential growth rate and a new Belehdradek-type model for evaluating the effect of temperature on growth rate. Food Microbiol 28:770-776.
  5. 231. Georgescu R, Langston L, O'Donnell M. 2015. A proposal: Evolution of PCNA's role as a marker of newly replicated DNA. DNA Repair 29:4-15.
  6. 246. Bradford MM. 1976. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem 72:248-254.
  7. 214. Kuhn J, Briegel A, Morschel E, Kahnt J, Leser K, Wick S, Jensen GJ, Thanbichler M. 2010. Bactofilins, a ubiquitous class of cytoskeletal proteins mediating polar localization of a cell wall synthase in Caulobacter crescentus. EMBO J 29:327-339.
  8. 184. Hirsch P. 1974. Budding bacteria. Annu Rev Microbiol 28:391-444.
  9. 191. Jensen RB, Shapiro L. 2003. Cell-cycle-regulated expression and subcellular localization of the Caulobacter crescentus SMC chromosome structural protein. J Bacteriol 185:3068-3075.
  10. 201. Ferullo DJ, Cooper DL, Moore HR, Lovett ST. 2009. Cell cycle synchronization of Escherichia coli using the stringent response, with fluorescence labeling assays for DNA content and replication. Methods 48:8-13.
  11. 222. Leicht O. 2012. Charakterisierung von Zellzyklusregulatoren in Hyphomonas neptunium. Master Thesis. Philipps-Universität Marburg.
  12. 194. Trojanowski D, Ginda K, Pioro M, Holowka J, Skut P, Jakimowicz D, ZakrzewskaCzerwinska J. 2015. Choreography of the Mycobacterium replication machinery during the cell cycle. MBio 6:e02125-02114.
  13. 193. Santi I, McKinney JD. 2015. Chromosome organization and replisome dynamics in Mycobacterium smegmatis. MBio 6:e01999-01914.
  14. 244. Laemmli UK. 1970. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature 227:680-685.
  15. 187. Eppinger M, Baar C, Raddatz G, Huson DH, Schuster SC. 2004. Comparative analysis of four Campylobacterales. Nat Rev Microbiol 2:872-885.
  16. 225. Broedersz CP, Wang X, Meir Y, Loparo JJ, Rudner DZ, Wingreen NS. 2014. Condensation and localization of the partitioning protein ParB on the bacterial chromosome. Proc Natl Acad Sci U S A 111:8809-8814.
  17. 238. Ausubel FM. 1988. Current protocols in molecular biology, Greene Pub. Associates ; WileyInterscience, New York.
  18. 207. Ben-Yehuda S, Fujita M, Liu XS, Gorbatyuk B, Skoko D, Yan J, Marko JF, Liu JS, Eichenberger P, Rudner DZ, Losick R. 2005. Defining a centromere-like element in Bacillus subtilis by identifying the binding sites for the chromosome-anchoring protein RacA. Mol Cell 17:773-782.
  19. 195. Kelman Z, Yuzhakov A, Andjelkovic J, O'Donnell M. 1998. Devoted to the lagging strand-the subunit of DNA polymerase III holoenzyme contacts SSB to promote processive elongation and sliding clamp assembly. EMBO J 17:2436-2449.
  20. 209. Thomaides HB, Freeman M, El Karoui M, Errington J. 2001. Division site selection protein DivIVA of Bacillus subtilis has a second distinct function in chromosome segregation during sporulation. Genes Dev 15:1662-1673.
  21. 232. Lenhart JS, Sharma A, Hingorani MM, Simmons LA. 2013. DnaN clamp zones provide a platform for spatiotemporal coupling of mismatch detection to DNA replication. Mol Microbiol 87:553-568.
  22. 216. Besprozvannaya M, Burton BM. 2014. Do the same traffic rules apply? Directional chromosome segregation by SpoIIIE and FtsK. Mol Microbiol 93:599-608.
  23. 212. Flardh K. 2003. Essential role of DivIVA in polar growth and morphogenesis in Streptomyces coelicolor A3(2). Mol Microbiol 49:1523-1536.
  24. 221. Leicht O. 2010. Etablierung eines genetischen Systems zur Analyse der Zellpolarität in Hyphomonas neptunium. Bachelor Thesis. Philipps-Universität Marburg.
  25. 183. Strobel W. 2010. Etablierung von genetischen Methoden zur Analyse der Zellteilung in Hyphomonas neptunium. Bachelor Thesis. Philipps-Universität Marburg.
  26. 240. Miller JH. 1972. Experiments in molecular genetics, Cold Spring Harbour Laboratory, Cold Spring Harbour, New York.
  27. 242. Moore RL, Hirsch P. 1973. First generation synchrony of isolated Hyphomicrobium swarmer populations. J Bacteriol 116:418-423.
  28. 217. Typas A, Banzhaf M, Gross CA, Vollmer W. 2012. From the regulation of peptidoglycan synthesis to bacterial growth and morphology. Nat Rev Microbiol 10:123-136.
  29. 219. Deghelt M, Mullier C, Sternon JF, Francis N, Laloux G, Dotreppe D, Van der Henst C, Jacobs-Wagner C, Letesson JJ, De Bolle X. 2014. G1-arrested newborn cells are the predominant infectious form of the pathogen Brucella abortus. Nat Commun 5:4366.
  30. 247. Nicholas KB, Nicholas HBJ. 1997. GeneDoc: a tool for editing and annotating multiple sequence alignments. Distributed by the author.
  31. 213. Ramamurthi KS, Lecuyer S, Stone HA, Losick R. 2009. Geometric cue for protein localization in a bacterium. Science 323:1354-1357.
  32. 226. Chen B-W, Lin M-H, Chu C-H, Hsu C-E, Sun Y-J. 2015. Insights into ParB spreading from the complex structure of Spo0J and parS. Proc Natl Acad Sci U S A 112:6613-6618.
  33. 236. Sharma A, Kamran M, Verma V, Dasgupta S, Dhar SK. 2014. Intracellular locations of replication proteins and the origin of replication during chromosome duplication in the slowly growing human pathogen Helicobacter pylori. J Bacteriol 196:999-1011.
  34. 208. Lenarcic R, Halbedel S, Visser L, Shaw M, Wu LJ, Errington J, Marenduzzo D, Hamoen LW. 2009. Localisation of DivIVA by targeting to negatively curved membranes. EMBO J 28:2272- 2282.
  35. 185. Spear AM, Loman NJ, Atkins HS, Pallen MJ. 2009. Microbial TIR domains: not necessarily agents of subversion? Trends Microbiol 17:393-398.
  36. 239. Sambrook J, Fritsch EF, Maniatis T. 1989. Molecular cloning: a laboratory manual., Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y.
  37. 230. Le TB, Laub MT. 2014. New approaches to understanding the spatial organization of bacterial genomes. Curr Opin Microbiol 22:15-21.
  38. 189. Bowman GR, Perez AM, Ptacin JL, Ighodaro E, Folta-Stogniew E, Comolli LR, Shapiro L. 2013. Oligomerization and higher-order assembly contribute to sub-cellular localization of a bacterial scaffold. Mol Microbiol 90:776-795.
  39. 243. Cameron TA, Anderson-Furgeson J, Zupan JR, Zik JJ, Zambryski PC. 2014. Peptidoglycan synthesis machinery in Agrobacterium tumefaciens during unipolar growth and cell division. MBio 5:e01219-01214.
  40. 220. Grangeon R, Zupan JR, Anderson-Furgeson J, Zambryski PC. 2015. PopZ identifies the new pole, and PodJ identifies the old pole during polar growth in Agrobacterium tumefaciens. Proc Natl Acad Sci U S A 112:11666-11671.
  41. 203. Ben-Yehuda S, Rudner DZ, Losick R. 2003. RacA, a bacterial protein that anchors chromosomes to the cell poles. Science 299:532-536.
  42. 204. Wu LJ, Errington J. 2003. RacA and the Soj-Spo0J system combine to effect polar chromosome segregation in sporulating Bacillus subtilis. Mol Microbiol 49:1463-1475.
  43. 234. Badrinarayanan A, Le TB, Laub MT. 2015. Rapid pairing and resegregation of distant homologous loci enables double-strand break repair in bacteria. J Cell Biol 210:385-400.
  44. 192. Dingwall A, Shapiro L. 1989. Rate, origin, and bidirectionality of Caulobacter chromosome replication as determined by pulsed-field gel electrophoresis. Proc Natl Acad Sci U S A 86:119-123.
  45. 235. Lesterlin C, Ball G, Schermelleh L, Sherratt DJ. 2014. RecA bundles mediate homology pairing between distant sisters during DNA break repair. Nature 506:249-253.
  46. 200. Courcelle J. 2005. Recs preventing wrecks. Mutat Res 577:217-227.
  47. 205. Treuner-Lange A, Sogaard-Andersen L. 2014. Regulation of cell polarity in bacteria. J Cell Biol 206:7-17.
  48. 224. Srivastava P, Fekete RA, Chattoraj DK. 2006. Segregation of the replication terminus of the two Vibrio cholerae chromosomes. J Bacteriol 188:1060-1070.
  49. 228. Lee JY, Finkelstein IJ, Arciszewska LK, Sherratt DJ, Greene EC. 2014. Single-molecule imaging of FtsK translocation reveals mechanistic features of protein-protein collisions on DNA. Mol Cell 54:832-843.
  50. 199. Pages V. 2016. Single-strand gap repair involves both RecF and RecBCD pathways. Curr Genet.
  51. 237. Lesterlin C, Gigant E, Boccard F, Espeli O. 2012. Sister chromatid interactions in bacteria revealed by a site-specific recombination assay. EMBO J 31:3468-3479.
  52. 233. Moolman MC, Krishnan ST, Kerssemakers JW, van den Berg A, Tulinski P, Depken M, Reyes-Lamothe R, Sherratt DJ, Dekker NH. 2014. Slow unloading leads to DNA-bound beta2- sliding clamp accumulation in live Escherichia coli cells. Nat Commun 5:5820.
  53. 248. Lau IF, Filipe SR, Soballe B, Okstad OA, Barre FX, Sherratt DJ. 2003. Spatial and temporal organization of replicating Escherichia coli chromosomes. Mol Microbiol 49:731-743.
  54. 190. Laloux G, Jacobs-Wagner C. 2013. Spatiotemporal control of PopZ localization through cell cycle-coupled multimerization. J Cell Biol 201:827-841.
  55. 229. Marquis KA, Burton BM, Nollmann M, Ptacin JL, Bustamante C, Ben-Yehuda S, Rudner DZ. 2008. SpoIIIE strips proteins off the DNA during chromosome translocation. Genes Dev 22:1786-1795.
  56. 227. Sanchez A, Cattoni Diego I, Walter J-C, Rech J, Parmeggiani A, Nollmann M, Bouet J-Y. Stochastic self-assembly of ParB proteins builds the bacterial DNA segregation apparatus. Cell Syst 1:163-173.
  57. 211. Meniche X, Otten R, Siegrist MS, Baer CE, Murphy KC, Bertozzi CR, Sassetti CM. 2014. Subpolar addition of new cell wall is directed by DivIVA in mycobacteria. Proc Natl Acad Sci U S A 111:E3243-3251.
  58. 197. Fernandez-Fernandez C, Grosse K, Sourjik V, Collier J. 2013. The beta-sliding clamp directs the localization of HdaA to the replisome in Caulobacter crescentus. Microbiology 159:2237-2248.
  59. 215. Yeh Y-C, Comolli LR, Downing KH, Shapiro L, McAdams HH. 2010. The Caulobacter Tol-Pal complex is essential for outer membrane integrity and the positioning of a polar localization factor. J Bacteriol 192:4847-4858.
  60. 188. Das D, Finn RD, Abdubek P, Astakhova T, Axelrod HL, Bakolitsa C, Cai X, Carlton D, Chen C, Chiu HJ, Chiu M, Clayton T, Deller MC, Duan L, Ellrott K, Farr CL, Feuerhelm J, Grant JC, Grzechnik A, Han GW, Jaroszewski L, Jin KK, Klock HE, Knuth MW, Kozbial P, Krishna SS, Kumar A, Lam WW, Marciano D, Miller MD, Morse AT, Nigoghossian E, Nopakun A, Okach L, Puckett C, Reyes R, Tien HJ, Trame CB, van den Bedem H, Weekes D, Wooten T, Xu Q, Yeh A, Zhou J, Hodgson KO, Wooley J, Elsliger MA, Deacon AM, Godzik A, Lesley SA, Wilson IA. 2010. The crystal structure of a bacterial Sufu-like protein defines a novel group of bacterial proteins that are similar to the N-terminal domain of human Sufu. Protein Sci 19:2131-2140.
  61. 210. Sieger B, Schubert K, Donovan C, Bramkamp M. 2013. The lipid II flippase RodA determines morphology and growth in Corynebacterium glutamicum. Mol Microbiol 90:966-982.
  62. 198. Su'etsugu M, Errington J. 2011. The replicase sliding clamp dynamically accumulates behind progressing replication forks in Bacillus subtilis cells. Mol Cell 41:720-732.
  63. 223. Li Y, Sergueev K, Austin S. 2002. The segregation of the Escherichia coli origin and terminus of replication. Mol Microbiol 46:985-996.
  64. 196. Meyer RR, Laine PS. 1990. The single-stranded DNA-binding protein of Escherichia coli. Microbiol Rev 54:342-380.
  65. 206. Bulyha I, Lindow S, Lin L, Bolte K, Wuichet K, Kahnt J, van der Does C, Thanbichler M, Sogaard-Andersen L. 2013. Two small GTPases act in concert with the bactofilin cytoskeleton to regulate dynamic bacterial cell polarity. Dev Cell 25:119-131.
  66. 202. Webb CD, Graumann PL, Kahana JA, Teleman AA, Silver PA, Losick R. 1998. Use of timelapse microscopy to visualize rapid movement of the replication origin region of the chromosome during the cell cycle in Bacillus subtilis. Mol Microbiol 28:883-892.
  67. 186. Mackiewicz P, Zakrzewska-Czerwinska J, Zawilak A, Dudek MR, Cebrat S. 2004. Where does bacterial replication start? Rules for predicting the oriC region. Nucleic Acids Res 32:3781- 3791.


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