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Nitrogen starvation-induced transcriptome alterations and influence of transcription regulator mutants in Mycobacterium smegmatis.

Jeßberger N, Lu Y, Amon J, Titgemeyer F, Sonnewald S, Reid S, Burkovski A - BMC Res Notes (2013)

Bottom Line: This includes changes in the transcription of several hundred genes encoding e.g. transport proteins, proteins involved in nitrogen metabolism and regulation, energy generation and protein turnover.The specific nitrogen-related changes at the transcriptional level depend mainly on the presence of GlnR, while the AmtR protein controls only a small number of genes.M. smegmatis is able to metabolize a number of different nitrogen sources and nitrogen control in M. smegmatis is similar to control mechanisms characterized in streptomycetes, while the master regulator of nitrogen control in corynebacteria, AmtR, is plays a minor role in this regulatory network.

View Article: PubMed Central - HTML - PubMed

Affiliation: Lehrstuhl für Mikrobiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany. aburkov@biologie.uni-erlangen.de.

ABSTRACT

Background: As other bacteria, Mycobacterium smegmatis needs adaption mechanisms to cope with changing nitrogen sources and to survive situations of nitrogen starvation. In the study presented here, transcriptome analyses were used to characterize the response of the bacterium to nitrogen starvation and to elucidate the role of specific transcriptional regulators.

Results: In response to nitrogen deprivation, a general starvation response is induced in M. smegmatis. This includes changes in the transcription of several hundred genes encoding e.g. transport proteins, proteins involved in nitrogen metabolism and regulation, energy generation and protein turnover. The specific nitrogen-related changes at the transcriptional level depend mainly on the presence of GlnR, while the AmtR protein controls only a small number of genes.

Conclusions: M. smegmatis is able to metabolize a number of different nitrogen sources and nitrogen control in M. smegmatis is similar to control mechanisms characterized in streptomycetes, while the master regulator of nitrogen control in corynebacteria, AmtR, is plays a minor role in this regulatory network.

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Test of AmtR binding by gel retardation assays. The indicated amounts of purified AmtR proteins were added to a 32P-labeled msmeg_2184 promoter fragment (437 bp) in the presence of 2ug sperm DNA (non-specific).
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Figure 9: Test of AmtR binding by gel retardation assays. The indicated amounts of purified AmtR proteins were added to a 32P-labeled msmeg_2184 promoter fragment (437 bp) in the presence of 2ug sperm DNA (non-specific).

Mentions: To verify direct AmtR-DNA interaction, M. smegmatis AmtR was overexpressed in Eschericha coli, purified and applied in gel retardation experiments. Binding of AmtR was tested for upstream DNA of msmeg_2184 and binding to the msmeg_2184 upstream region was demonstrated (Figure 9). Since TetR-type regulators often bind small effector molecules that induce release of the repressor from its binding site, addition of putative AmtR effectors deduced from the putative function of target genes, i.e. urea and different amino acids, were tested in various concentrations (0.5 to 5 mM) but had no influence on binding to the msmeg_2184 upstream region (data not shown).


Nitrogen starvation-induced transcriptome alterations and influence of transcription regulator mutants in Mycobacterium smegmatis.

Jeßberger N, Lu Y, Amon J, Titgemeyer F, Sonnewald S, Reid S, Burkovski A - BMC Res Notes (2013)

Test of AmtR binding by gel retardation assays. The indicated amounts of purified AmtR proteins were added to a 32P-labeled msmeg_2184 promoter fragment (437 bp) in the presence of 2ug sperm DNA (non-specific).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4222082&req=5

Figure 9: Test of AmtR binding by gel retardation assays. The indicated amounts of purified AmtR proteins were added to a 32P-labeled msmeg_2184 promoter fragment (437 bp) in the presence of 2ug sperm DNA (non-specific).
Mentions: To verify direct AmtR-DNA interaction, M. smegmatis AmtR was overexpressed in Eschericha coli, purified and applied in gel retardation experiments. Binding of AmtR was tested for upstream DNA of msmeg_2184 and binding to the msmeg_2184 upstream region was demonstrated (Figure 9). Since TetR-type regulators often bind small effector molecules that induce release of the repressor from its binding site, addition of putative AmtR effectors deduced from the putative function of target genes, i.e. urea and different amino acids, were tested in various concentrations (0.5 to 5 mM) but had no influence on binding to the msmeg_2184 upstream region (data not shown).

Bottom Line: This includes changes in the transcription of several hundred genes encoding e.g. transport proteins, proteins involved in nitrogen metabolism and regulation, energy generation and protein turnover.The specific nitrogen-related changes at the transcriptional level depend mainly on the presence of GlnR, while the AmtR protein controls only a small number of genes.M. smegmatis is able to metabolize a number of different nitrogen sources and nitrogen control in M. smegmatis is similar to control mechanisms characterized in streptomycetes, while the master regulator of nitrogen control in corynebacteria, AmtR, is plays a minor role in this regulatory network.

View Article: PubMed Central - HTML - PubMed

Affiliation: Lehrstuhl für Mikrobiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany. aburkov@biologie.uni-erlangen.de.

ABSTRACT

Background: As other bacteria, Mycobacterium smegmatis needs adaption mechanisms to cope with changing nitrogen sources and to survive situations of nitrogen starvation. In the study presented here, transcriptome analyses were used to characterize the response of the bacterium to nitrogen starvation and to elucidate the role of specific transcriptional regulators.

Results: In response to nitrogen deprivation, a general starvation response is induced in M. smegmatis. This includes changes in the transcription of several hundred genes encoding e.g. transport proteins, proteins involved in nitrogen metabolism and regulation, energy generation and protein turnover. The specific nitrogen-related changes at the transcriptional level depend mainly on the presence of GlnR, while the AmtR protein controls only a small number of genes.

Conclusions: M. smegmatis is able to metabolize a number of different nitrogen sources and nitrogen control in M. smegmatis is similar to control mechanisms characterized in streptomycetes, while the master regulator of nitrogen control in corynebacteria, AmtR, is plays a minor role in this regulatory network.

Show MeSH
Related in: MedlinePlus