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. 2002 Mar 15;362(Pt 3):579–584. doi: 10.1042/0264-6021:3620579

Impaired chromosome partitioning and synchronization of DNA replication initiation in an insertional mutant in the Vibrio harveyi cgtA gene coding for a common GTP-binding protein.

Monika Słomińska 1, Grazyna Konopa 1, Grzegorz Wegrzyn 1, Agata Czyz 1
PMCID: PMC1222421  PMID: 11879184

Abstract

The Vibrio harveyi cgtA gene product belongs to a subfamily of small GTP-binding proteins, called Obg-like proteins. Members of this subfamily are present in diverse organisms ranging from bacteria to humans. On the other hand, the functions of these proteins in the regulation of cellular processes are largely unknown. Genes coding for these proteins are essential in almost all bacteria investigated thus far. However, a viable V. harveyi insertional mutant in the cgtA gene was described recently. Therefore, this mutant gives a unique opportunity to study functions of a member of the subfamily of Obg-like proteins. Here we demonstrate that the mutant cells often form long filaments with expanded, non-partitioned or rarely partitioned chromosomes. Such a phenotype suggests impairment of the mechanism of chromosome partition. Flow cytometric studies revealed that synchronization of chromosome replication initiation is also significantly disturbed in the cgtA mutant. Moreover, in contrast to wild-type V. harveyi, inhibition of chromosome replication and/or of cell division in the mutant bacteria caused significant increase in the number of large cells, suggesting that the cgtA gene product may be involved in the coupling of cell growth to chromosome replication and cell division. These results indicate that CgtA, an Obg-like GTP-binding protein, plays an important role in the regulation of chromosomal functions.

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Selected References

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  1. Arigoni F., Talabot F., Peitsch M., Edgerton M. D., Meldrum E., Allet E., Fish R., Jamotte T., Curchod M. L., Loferer H. A genome-based approach for the identification of essential bacterial genes. Nat Biotechnol. 1998 Sep;16(9):851–856. doi: 10.1038/nbt0998-851. [DOI] [PubMed] [Google Scholar]
  2. Belas R., Mileham A., Cohn D., Hilman M., Simon M., Silverman M. Bacterial bioluminescence: isolation and expression of the luciferase genes from Vibrio harveyi. Science. 1982 Nov 19;218(4574):791–793. doi: 10.1126/science.10636771. [DOI] [PubMed] [Google Scholar]
  3. Czyz A., Jasiecki J., Bogdan A., Szpilewska H., Wegrzyn G. Genetically modified Vibrio harveyi strains as potential bioindicators of mutagenic pollution of marine environments. Appl Environ Microbiol. 2000 Feb;66(2):599–605. doi: 10.1128/aem.66.2.599-605.2000. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Czyz A., Zielke R., Konopa G., Wegrzyn G. A Vibrio harveyi insertional mutant in the cgtA (obg, yhbZ) gene, whose homologues are present in diverse organisms ranging from bacteria to humans and are essential genes in many bacterial species. Microbiology. 2001 Jan;147(Pt 1):183–191. doi: 10.1099/00221287-147-1-183. [DOI] [PubMed] [Google Scholar]
  5. Klein G., Walczak R., Krasnowska E., Blaszczak A., Lipińska B. Characterization of heat-shock response of the marine bacterium Vibrio harveyi. Mol Microbiol. 1995 May;16(4):801–811. doi: 10.1111/j.1365-2958.1995.tb02441.x. [DOI] [PubMed] [Google Scholar]
  6. Kok J., Trach K. A., Hoch J. A. Effects on Bacillus subtilis of a conditional lethal mutation in the essential GTP-binding protein Obg. J Bacteriol. 1994 Dec;176(23):7155–7160. doi: 10.1128/jb.176.23.7155-7160.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Maddock J., Bhatt A., Koch M., Skidmore J. Identification of an essential Caulobacter crescentus gene encoding a member of the Obg family of GTP-binding proteins. J Bacteriol. 1997 Oct;179(20):6426–6431. doi: 10.1128/jb.179.20.6426-6431.1997. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Okamoto S., Itoh M., Ochi K. Molecular cloning and characterization of the obg gene of Streptomyces griseus in relation to the onset of morphological differentiation. J Bacteriol. 1997 Jan;179(1):170–179. doi: 10.1128/jb.179.1.170-179.1997. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Okamoto S., Ochi K. An essential GTP-binding protein functions as a regulator for differentiation in Streptomyces coelicolor. Mol Microbiol. 1998 Oct;30(1):107–119. doi: 10.1046/j.1365-2958.1998.01042.x. [DOI] [PubMed] [Google Scholar]
  10. Park J. H., Jensen B. C., Kifer C. T., Parsons M. A novel nucleolar G-protein conserved in eukaryotes. J Cell Sci. 2001 Jan;114(Pt 1):173–185. doi: 10.1242/jcs.114.1.173. [DOI] [PubMed] [Google Scholar]
  11. Scott J. M., Haldenwang W. G. Obg, an essential GTP binding protein of Bacillus subtilis, is necessary for stress activation of transcription factor sigma(B). J Bacteriol. 1999 Aug;181(15):4653–4660. doi: 10.1128/jb.181.15.4653-4660.1999. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Scott J. M., Ju J., Mitchell T., Haldenwang W. G. The Bacillus subtilis GTP binding protein obg and regulators of the sigma(B) stress response transcription factor cofractionate with ribosomes. J Bacteriol. 2000 May;182(10):2771–2777. doi: 10.1128/jb.182.10.2771-2777.2000. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Stewart P. S., D'Ari R. Genetic and morphological characterization of an Escherichia coli chromosome segregation mutant. J Bacteriol. 1992 Jul;174(13):4513–4516. doi: 10.1128/jb.174.13.4513-4516.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Torheim N. K., Boye E., Løbner-Olesen A., Stokke T., Skarstad K. The Escherichia coli SeqA protein destabilizes mutant DnaA204 protein. Mol Microbiol. 2000 Aug;37(3):629–638. doi: 10.1046/j.1365-2958.2000.02031.x. [DOI] [PubMed] [Google Scholar]
  15. Trach K., Hoch J. A. The Bacillus subtilis spo0B stage 0 sporulation operon encodes an essential GTP-binding protein. J Bacteriol. 1989 Mar;171(3):1362–1371. doi: 10.1128/jb.171.3.1362-1371.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Vidwans S. J., Ireton K., Grossman A. D. Possible role for the essential GTP-binding protein Obg in regulating the initiation of sporulation in Bacillus subtilis. J Bacteriol. 1995 Jun;177(11):3308–3311. doi: 10.1128/jb.177.11.3308-3311.1995. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Wegrzyn G., Kwaśnik E., Taylor K. Replication of lambda plasmid in amino acid-starved strains of Escherichia coli. Acta Biochim Pol. 1991;38(1):181–186. [PubMed] [Google Scholar]

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