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Patterns and regulation of ribosomal RNA transcription in Borrelia burgdorferi.

Bugrysheva JV, Godfrey HP, Schwartz I, Cabello FC - BMC Microbiol. (2011)

Bottom Line: DNA per cell was higher in cells in exponential as compared to stationary phase at either temperature; protein per cell was similar at both temperatures in both phases.Interestingly, a rel Bbu deletion mutant unable to generate (p)ppGpp did not down-regulate rRNA at transition to stationary phase in serum-containing BSK-H at 34°C, similar to the relaxed phenotype of E. coli relA mutants.We conclude that rRNA transcription in B. burgdorferi is complex and regulated both by growth phase and by the stringent response but not by temperature-modulated growth rate.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Microbiology and Immunology, Basic Science Building, New York Medical College, Valhalla, NY 10595, USA.

ABSTRACT

Background: Borrelia burgdorferi contains one 16S and two tandem sets of 23S-5S ribosomal (r) RNA genes whose patterns of transcription and regulation are unknown but are likely to be critical for survival and persistence in its hosts.

Results: RT-PCR of B. burgdorferi N40 and B31 revealed three rRNA region transcripts: 16S rRNA-alanine transfer RNA (tRNA Ala); tRNA Ile; and both sets of 23S-5S rRNA. At 34°C, there were no differences in growth rate or in accumulation of total protein, DNA and RNA in B31 cultured in Barbour-Stoenner-Kelly (BSK)-H whether rabbit serum was present or not. At 23°C, B31 grew more slowly in serum-containing BSK-H than at 34°C. DNA per cell was higher in cells in exponential as compared to stationary phase at either temperature; protein per cell was similar at both temperatures in both phases. Similar amounts of rRNA were produced in exponential phase at both temperatures, and rRNA was down-regulated in stationary phase at either temperature. Interestingly, a rel Bbu deletion mutant unable to generate (p)ppGpp did not down-regulate rRNA at transition to stationary phase in serum-containing BSK-H at 34°C, similar to the relaxed phenotype of E. coli relA mutants.

Conclusions: We conclude that rRNA transcription in B. burgdorferi is complex and regulated both by growth phase and by the stringent response but not by temperature-modulated growth rate.

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Cell growth (A) and expression of 16S (B) and 23S (C) rRNA (mean ± SE) normalized to flaB mRNA in wild-type (solid circle) and ΔrelBbu (open circle) B. burgdorferi 297 grown in complete BSK-H at 34°C. Data are presented relative to normalized rRNA expression at day two of wild-type cell culture as described in Materials and Methods.
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Figure 6: Cell growth (A) and expression of 16S (B) and 23S (C) rRNA (mean ± SE) normalized to flaB mRNA in wild-type (solid circle) and ΔrelBbu (open circle) B. burgdorferi 297 grown in complete BSK-H at 34°C. Data are presented relative to normalized rRNA expression at day two of wild-type cell culture as described in Materials and Methods.

Mentions: To examine if the stringent response regulated rRNA levels in this bacterium, B. burgdorferi 297 and its ΔrelBbu derivative that could not synthesize (p)ppGpp were used [19]. Both strains multiplied at a similar rate in exponential phase in BSK-H at 34°C (Figure 6A) but the deletion mutant stopped dividing after day four of culture while densities of the wild-type strain continued to increase (Figure 6A). In wild-type B. burgdorferi, 16S and 23S rRNA levels were very similar at 2 to 4 days of culture and decreased only slightly toward the end of the growth curve when the culture was reaching its maximum density and increased its doubling time (Figures 6B, C). In contrast, rRNA levels in B. burgdorferi ΔrelBbu peaked at day five for both rRNA species, the first day of culture when cell densities of ΔrelBbu did not increase (Figure 6). The reverse correlation between cell division and rRNA accumulation in B. burgdorferi ΔrelBbu strongly suggests that relBbu is necessary for stringent control of rRNA synthesis in B. burgdorferi. This accumulation of rRNA is reminiscent of what occurs in the relaxed phenotype of E. coli relA mutants [9,24,25].


Patterns and regulation of ribosomal RNA transcription in Borrelia burgdorferi.

Bugrysheva JV, Godfrey HP, Schwartz I, Cabello FC - BMC Microbiol. (2011)

Cell growth (A) and expression of 16S (B) and 23S (C) rRNA (mean ± SE) normalized to flaB mRNA in wild-type (solid circle) and ΔrelBbu (open circle) B. burgdorferi 297 grown in complete BSK-H at 34°C. Data are presented relative to normalized rRNA expression at day two of wild-type cell culture as described in Materials and Methods.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3037291&req=5

Figure 6: Cell growth (A) and expression of 16S (B) and 23S (C) rRNA (mean ± SE) normalized to flaB mRNA in wild-type (solid circle) and ΔrelBbu (open circle) B. burgdorferi 297 grown in complete BSK-H at 34°C. Data are presented relative to normalized rRNA expression at day two of wild-type cell culture as described in Materials and Methods.
Mentions: To examine if the stringent response regulated rRNA levels in this bacterium, B. burgdorferi 297 and its ΔrelBbu derivative that could not synthesize (p)ppGpp were used [19]. Both strains multiplied at a similar rate in exponential phase in BSK-H at 34°C (Figure 6A) but the deletion mutant stopped dividing after day four of culture while densities of the wild-type strain continued to increase (Figure 6A). In wild-type B. burgdorferi, 16S and 23S rRNA levels were very similar at 2 to 4 days of culture and decreased only slightly toward the end of the growth curve when the culture was reaching its maximum density and increased its doubling time (Figures 6B, C). In contrast, rRNA levels in B. burgdorferi ΔrelBbu peaked at day five for both rRNA species, the first day of culture when cell densities of ΔrelBbu did not increase (Figure 6). The reverse correlation between cell division and rRNA accumulation in B. burgdorferi ΔrelBbu strongly suggests that relBbu is necessary for stringent control of rRNA synthesis in B. burgdorferi. This accumulation of rRNA is reminiscent of what occurs in the relaxed phenotype of E. coli relA mutants [9,24,25].

Bottom Line: DNA per cell was higher in cells in exponential as compared to stationary phase at either temperature; protein per cell was similar at both temperatures in both phases.Interestingly, a rel Bbu deletion mutant unable to generate (p)ppGpp did not down-regulate rRNA at transition to stationary phase in serum-containing BSK-H at 34°C, similar to the relaxed phenotype of E. coli relA mutants.We conclude that rRNA transcription in B. burgdorferi is complex and regulated both by growth phase and by the stringent response but not by temperature-modulated growth rate.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Microbiology and Immunology, Basic Science Building, New York Medical College, Valhalla, NY 10595, USA.

ABSTRACT

Background: Borrelia burgdorferi contains one 16S and two tandem sets of 23S-5S ribosomal (r) RNA genes whose patterns of transcription and regulation are unknown but are likely to be critical for survival and persistence in its hosts.

Results: RT-PCR of B. burgdorferi N40 and B31 revealed three rRNA region transcripts: 16S rRNA-alanine transfer RNA (tRNA Ala); tRNA Ile; and both sets of 23S-5S rRNA. At 34°C, there were no differences in growth rate or in accumulation of total protein, DNA and RNA in B31 cultured in Barbour-Stoenner-Kelly (BSK)-H whether rabbit serum was present or not. At 23°C, B31 grew more slowly in serum-containing BSK-H than at 34°C. DNA per cell was higher in cells in exponential as compared to stationary phase at either temperature; protein per cell was similar at both temperatures in both phases. Similar amounts of rRNA were produced in exponential phase at both temperatures, and rRNA was down-regulated in stationary phase at either temperature. Interestingly, a rel Bbu deletion mutant unable to generate (p)ppGpp did not down-regulate rRNA at transition to stationary phase in serum-containing BSK-H at 34°C, similar to the relaxed phenotype of E. coli relA mutants.

Conclusions: We conclude that rRNA transcription in B. burgdorferi is complex and regulated both by growth phase and by the stringent response but not by temperature-modulated growth rate.

Show MeSH