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Serine/threonine protein kinase SpkG is a candidate for high salt resistance in the unicellular cyanobacterium Synechocystis sp. PCC 6803.

Liang C, Zhang X, Chi X, Guan X, Li Y, Qin S, Shao HB - PLoS ONE (2011)

Bottom Line: To further confirm the function of spkG, we also examined the effect of mutation of spkG on the expression of salt stress-inducible genes.We compared genome-wide patterns of transcription between wild-type Synechocystis sp.Our microarray experiment may help select relatively significant genes for further research on mechanisms of signal transduction of Synechocystis sp.

View Article: PubMed Central - PubMed

Affiliation: Qingdao University of Science and Technology, Qingdao, China.

ABSTRACT

Background: Seven serine/threonine kinase genes have been predicted in unicellular cyanobacterium Synechocystis sp. PCC6803. SpkA and SpkB were shown to be required for cell motility and SpkE has no kinase activity. There is no report whether the other four STKs are involved in stress-mediated signaling in Synechocystis PCC6803.

Methodology/principal findings: In this paper, we examined differential expression of the other four serine/threonine kinases, SpkC, SpkD, SpkF and SpkG, at seven different stress conditions. The transcriptional level was up-regulated of spkG and down-regulated of spkC under high salt stress condition. Two spk deletion mutants, ΔspkC and ΔspkG, were constructed and their growth characteristic were examined compared to the wild strain. The wild strain and ΔspkC mutant were not affected under high salt stress conditions. In contrast, growth of spkG mutant was completely impaired. To further confirm the function of spkG, we also examined the effect of mutation of spkG on the expression of salt stress-inducible genes. We compared genome-wide patterns of transcription between wild-type Synechocystis sp. PCC6803 and cells with a mutation in the SpkG with DNA microarray analysis.

Conclusion: In this study, we first study the spkG gene as sensor of high salt signal. We consider that SpkG play essential roles in Synechocystis sp. for sensing the high salt signal directly, rather than mediating signals among other kinases. Our microarray experiment may help select relatively significant genes for further research on mechanisms of signal transduction of Synechocystis sp. PCC6803 under high salt stress.

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Related in: MedlinePlus

Growth properties of wild strain (circles) and ΔspkC (rectangles) and ΔspkG (triangles) mutants at normal (filled symbols) and high salt (empty symbols) stress conditions.To determine the reliability of these data, each experiment was performed three times. Data are from one representative experiment.
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pone-0018718-g003: Growth properties of wild strain (circles) and ΔspkC (rectangles) and ΔspkG (triangles) mutants at normal (filled symbols) and high salt (empty symbols) stress conditions.To determine the reliability of these data, each experiment was performed three times. Data are from one representative experiment.

Mentions: To further affirm the probable functions of SpkC and SpkG in high salt stress, two mutants, ΔspkC and ΔspkG, were generated by replacing part sequences of these two genes with kanamycin resistance cassettes (Fig. 2A) and the complete segregation of mutants were verified by PCR analysis (Fig. 2B). We examined the growth of ΔspkC and ΔspkG mutants under standard and high salt-stress conditions compared to that of the wild strain. The growth properties of the two mutants were not significant changed compared to the wild strain under normal conditions. The presence of 684 mM NaCl, the same condition with RT-PCR, in the growth medium has no effect on the growth of ΔspkC, ΔspkG and wild strain (data not shown). Whereas, the growth of the ΔspkG mutant strain was almost completely impaired at 855 mM NaCl conditions in contrast to the wild strain and ΔspkC mutant, which were unaffected (Fig. 3). During their long evolution, cyanobacteria have adapted to aquatic habitats with various salt concentrations [24]. Synechocystis sp. PCC6803 has the ability to regulate essential metabolic processes to enable survival in high salt environments [25]. This result indicates that SpkG may be involved in adaptation to high salt stress condition. In our previous work, we predicted that SpkG has four strong transmembrane helices by the TMbase (www.ch.embnet.org/software/TMPRED_form.html) [13]. So we predicted that SpkG could sense the high salt signal directly, rather than mediate signals among other kinases.


Serine/threonine protein kinase SpkG is a candidate for high salt resistance in the unicellular cyanobacterium Synechocystis sp. PCC 6803.

Liang C, Zhang X, Chi X, Guan X, Li Y, Qin S, Shao HB - PLoS ONE (2011)

Growth properties of wild strain (circles) and ΔspkC (rectangles) and ΔspkG (triangles) mutants at normal (filled symbols) and high salt (empty symbols) stress conditions.To determine the reliability of these data, each experiment was performed three times. Data are from one representative experiment.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3102658&req=5

pone-0018718-g003: Growth properties of wild strain (circles) and ΔspkC (rectangles) and ΔspkG (triangles) mutants at normal (filled symbols) and high salt (empty symbols) stress conditions.To determine the reliability of these data, each experiment was performed three times. Data are from one representative experiment.
Mentions: To further affirm the probable functions of SpkC and SpkG in high salt stress, two mutants, ΔspkC and ΔspkG, were generated by replacing part sequences of these two genes with kanamycin resistance cassettes (Fig. 2A) and the complete segregation of mutants were verified by PCR analysis (Fig. 2B). We examined the growth of ΔspkC and ΔspkG mutants under standard and high salt-stress conditions compared to that of the wild strain. The growth properties of the two mutants were not significant changed compared to the wild strain under normal conditions. The presence of 684 mM NaCl, the same condition with RT-PCR, in the growth medium has no effect on the growth of ΔspkC, ΔspkG and wild strain (data not shown). Whereas, the growth of the ΔspkG mutant strain was almost completely impaired at 855 mM NaCl conditions in contrast to the wild strain and ΔspkC mutant, which were unaffected (Fig. 3). During their long evolution, cyanobacteria have adapted to aquatic habitats with various salt concentrations [24]. Synechocystis sp. PCC6803 has the ability to regulate essential metabolic processes to enable survival in high salt environments [25]. This result indicates that SpkG may be involved in adaptation to high salt stress condition. In our previous work, we predicted that SpkG has four strong transmembrane helices by the TMbase (www.ch.embnet.org/software/TMPRED_form.html) [13]. So we predicted that SpkG could sense the high salt signal directly, rather than mediate signals among other kinases.

Bottom Line: To further confirm the function of spkG, we also examined the effect of mutation of spkG on the expression of salt stress-inducible genes.We compared genome-wide patterns of transcription between wild-type Synechocystis sp.Our microarray experiment may help select relatively significant genes for further research on mechanisms of signal transduction of Synechocystis sp.

View Article: PubMed Central - PubMed

Affiliation: Qingdao University of Science and Technology, Qingdao, China.

ABSTRACT

Background: Seven serine/threonine kinase genes have been predicted in unicellular cyanobacterium Synechocystis sp. PCC6803. SpkA and SpkB were shown to be required for cell motility and SpkE has no kinase activity. There is no report whether the other four STKs are involved in stress-mediated signaling in Synechocystis PCC6803.

Methodology/principal findings: In this paper, we examined differential expression of the other four serine/threonine kinases, SpkC, SpkD, SpkF and SpkG, at seven different stress conditions. The transcriptional level was up-regulated of spkG and down-regulated of spkC under high salt stress condition. Two spk deletion mutants, ΔspkC and ΔspkG, were constructed and their growth characteristic were examined compared to the wild strain. The wild strain and ΔspkC mutant were not affected under high salt stress conditions. In contrast, growth of spkG mutant was completely impaired. To further confirm the function of spkG, we also examined the effect of mutation of spkG on the expression of salt stress-inducible genes. We compared genome-wide patterns of transcription between wild-type Synechocystis sp. PCC6803 and cells with a mutation in the SpkG with DNA microarray analysis.

Conclusion: In this study, we first study the spkG gene as sensor of high salt signal. We consider that SpkG play essential roles in Synechocystis sp. for sensing the high salt signal directly, rather than mediating signals among other kinases. Our microarray experiment may help select relatively significant genes for further research on mechanisms of signal transduction of Synechocystis sp. PCC6803 under high salt stress.

Show MeSH
Related in: MedlinePlus