Limits...
Identification of possible targets of the Aspergillus fumigatus CRZ1 homologue, CrzA.

Soriani FM, Malavazi I, Savoldi M, Espeso E, Dinamarco TM, Bernardes LA, Ferreira ME, Goldman MH, Goldman GH - BMC Microbiol. (2010)

Bottom Line: GFP::RcnA was mostly detected along the germling, did not accumulate in the nuclei and its location is not affected by the cellular response to calcium chloride.AfRcnA, one of these selected genes, encodes a modulator of calcineurin activity.A. nidulans AnRcnA mutation is suppressing CnaA mutation and it is responsible for modulating the calcineurin activity and mRNA accumulation of genes encoding calcium transporters.

View Article: PubMed Central - HTML - PubMed

Affiliation: Centro de Ciência e Tecnologia do Bioetanol and Faculdade de Ciências Farmacêuticas de Ribeirão Preto Universidade de São Paulo, São Paulo, Ribeirão Preto 14040-903, Brazil.

ABSTRACT

Background: Calcineurin, a serine/threonine-specific protein phosphatase, plays an important role in the control of cell morphology and virulence in fungi. Calcineurin regulates localization and activity of a transcription factor called CRZ1. Recently, we characterize Aspergillus fumigatus CRZ1 homologue, AfCrzA. Here, we investigate which pathways are influenced by A. fumigatus AfCrzA during a short pulse of calcium by comparatively determining the transcriptional profile of A. fumigatus wild type and DeltaAfcrzA mutant strains.

Results: We were able to observe 3,622 genes modulated in at least one timepoint in the mutant when compared to the wild type strain (3,211 and 411 at 10 and 30 minutes, respectively). Decreased mRNA abundance in the DeltacrzA was seen for genes encoding calcium transporters, transcription factors and genes that could be directly or indirectly involved in calcium metabolism. Increased mRNA accumulation was observed for some genes encoding proteins involved in stress response. AfCrzA overexpression in A. fumigatus increases the expression of several of these genes. The deleted strain of one of these genes, AfRcnA, belonging to a class of endogenous calcineurin regulators, calcipressins, had more calcineurin activity after exposure to calcium and was less sensitive to menadione 30 microM, hydrogen peroxide 2.5 mM, EGTA 25 mM, and MnCl2 25 mM. We constructed deletion, overexpression, and GFP fusion protein for the closely related A. nidulans AnRcnA. GFP::RcnA was mostly detected along the germling, did not accumulate in the nuclei and its location is not affected by the cellular response to calcium chloride.

Conclusion: We have performed a transcriptional profiling analysis of the A. fumigatus DeltaAfcrzA mutant strain exposed to calcium stress. This provided an excellent opportunity to identify genes and pathways that are under the influence of AfCrzA. AfRcnA, one of these selected genes, encodes a modulator of calcineurin activity. Concomitantly with A. fumigatus AfrcnA molecular analysis, we decided to exploit the conserved features of A. nidulans calcineurin system and investigated the A. nidulans AnRcnA homologue. A. nidulans AnRcnA mutation is suppressing CnaA mutation and it is responsible for modulating the calcineurin activity and mRNA accumulation of genes encoding calcium transporters.

Show MeSH

Related in: MedlinePlus

Molecular characterization of the A. fumigatus AfrcnA. (A) Schematic illustration of the rcnA deletion strategy. (A) Genomic DNA from both wild type and ΔAfrcnA strains was isolated and cleaved with the enzyme EcoRI; a 2.0-kb DNA fragment from the 5'-noncoding region was used as a hybridization probe. This fragment recognizes a single DNA band (about 9.8-kb) in the wild type strain and also a single DNA band (about 3.6-kb) in the ΔrcnA mutant as shown in the Southern blot analysis. (B) Wild type and ΔAfrcnA mutant strains were grown for 72 hours at 37°C in complete medium in the absence or presence of menadione 30 μM, H2O2 2.5 mM, cyclosporine A 600 ng/ml, EGTA 25 mM, and MnCl2 25 mM. The graph shows the radial growth (cm) of the strains under different growth conditions. The results are the means ± standard deviation of four sets of experiments. (C) Wild type and ΔrcnA mutant strains were grown in YG medium for 16 hours at 37°C and then exposed to 200 mM CaCl2 for 10 minutes. Mycelial protein extracts were processed and calcineurin activity measured. Asterisks indicate the ΔrcnA samples are significantly different from the wild type strain (p < 0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2818617&req=5

Figure 4: Molecular characterization of the A. fumigatus AfrcnA. (A) Schematic illustration of the rcnA deletion strategy. (A) Genomic DNA from both wild type and ΔAfrcnA strains was isolated and cleaved with the enzyme EcoRI; a 2.0-kb DNA fragment from the 5'-noncoding region was used as a hybridization probe. This fragment recognizes a single DNA band (about 9.8-kb) in the wild type strain and also a single DNA band (about 3.6-kb) in the ΔrcnA mutant as shown in the Southern blot analysis. (B) Wild type and ΔAfrcnA mutant strains were grown for 72 hours at 37°C in complete medium in the absence or presence of menadione 30 μM, H2O2 2.5 mM, cyclosporine A 600 ng/ml, EGTA 25 mM, and MnCl2 25 mM. The graph shows the radial growth (cm) of the strains under different growth conditions. The results are the means ± standard deviation of four sets of experiments. (C) Wild type and ΔrcnA mutant strains were grown in YG medium for 16 hours at 37°C and then exposed to 200 mM CaCl2 for 10 minutes. Mycelial protein extracts were processed and calcineurin activity measured. Asterisks indicate the ΔrcnA samples are significantly different from the wild type strain (p < 0.05).

Mentions: To have more information about the function of some of the genes identified as more expressed in the A. fumigatus wild type and repressed in the ΔAfcrzA, we inactivated the AfrcnA (Afu2g13060), AfrfeF (Afu4g10200), Af BAR adaptor protein (Afu3g14230), and A. fumigatus phospholipase D (Afu2g16520). Since calcium is involved in different kinds of stresses, such as oxidative stress and uncontrolled proliferation and survival [38-44], we decided to determine if several different culture conditions could affect the growth of these deletion strains. Except for ΔAfrcnA, the deletion mutants showed comparable growth phenotypes to the wild type strain in the presence of the following agents or stressing situations: oxidizing agents and metals (paraquat, t-butyl hydroperoxide, zinc, iron, and chromium), calcium, cyclosporine A, DNA damaging agents (4-nitroquinoline oxide, hydroxyurea, camptothecin, and bleomycin), and temperature (30, 37, and 44°C) (data not shown). However, ΔAfrcnA growth was less sensitive to menadione 30 μM, hydrogen peroxide 2.5 mM, EGTA 25 mM, and MnCl2 25 mM (Figure 4B). We exposed both wild type and ΔAfrcnA strains for 200 mM calcium chloride for 10 minutes and measured the calcineurin activity in these strains (Figure 4C). In the wild type strain, there is about 50% increase in the calcineurin activity when the mycelia was exposed to calcium chloride 200 mM for 10 minutes (Figure 4C). However, in the ΔAfrcnA mutant strain there is a significant increase in the calcineurin activity at 0 and 10 minutes in the presence of calcium chloride (Figure 4C). These results suggest that AfRcnA has an inhibitory effect on calcineurin activity when A. fumigatus is exposed to high calcium concentrations.


Identification of possible targets of the Aspergillus fumigatus CRZ1 homologue, CrzA.

Soriani FM, Malavazi I, Savoldi M, Espeso E, Dinamarco TM, Bernardes LA, Ferreira ME, Goldman MH, Goldman GH - BMC Microbiol. (2010)

Molecular characterization of the A. fumigatus AfrcnA. (A) Schematic illustration of the rcnA deletion strategy. (A) Genomic DNA from both wild type and ΔAfrcnA strains was isolated and cleaved with the enzyme EcoRI; a 2.0-kb DNA fragment from the 5'-noncoding region was used as a hybridization probe. This fragment recognizes a single DNA band (about 9.8-kb) in the wild type strain and also a single DNA band (about 3.6-kb) in the ΔrcnA mutant as shown in the Southern blot analysis. (B) Wild type and ΔAfrcnA mutant strains were grown for 72 hours at 37°C in complete medium in the absence or presence of menadione 30 μM, H2O2 2.5 mM, cyclosporine A 600 ng/ml, EGTA 25 mM, and MnCl2 25 mM. The graph shows the radial growth (cm) of the strains under different growth conditions. The results are the means ± standard deviation of four sets of experiments. (C) Wild type and ΔrcnA mutant strains were grown in YG medium for 16 hours at 37°C and then exposed to 200 mM CaCl2 for 10 minutes. Mycelial protein extracts were processed and calcineurin activity measured. Asterisks indicate the ΔrcnA samples are significantly different from the wild type strain (p < 0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2818617&req=5

Figure 4: Molecular characterization of the A. fumigatus AfrcnA. (A) Schematic illustration of the rcnA deletion strategy. (A) Genomic DNA from both wild type and ΔAfrcnA strains was isolated and cleaved with the enzyme EcoRI; a 2.0-kb DNA fragment from the 5'-noncoding region was used as a hybridization probe. This fragment recognizes a single DNA band (about 9.8-kb) in the wild type strain and also a single DNA band (about 3.6-kb) in the ΔrcnA mutant as shown in the Southern blot analysis. (B) Wild type and ΔAfrcnA mutant strains were grown for 72 hours at 37°C in complete medium in the absence or presence of menadione 30 μM, H2O2 2.5 mM, cyclosporine A 600 ng/ml, EGTA 25 mM, and MnCl2 25 mM. The graph shows the radial growth (cm) of the strains under different growth conditions. The results are the means ± standard deviation of four sets of experiments. (C) Wild type and ΔrcnA mutant strains were grown in YG medium for 16 hours at 37°C and then exposed to 200 mM CaCl2 for 10 minutes. Mycelial protein extracts were processed and calcineurin activity measured. Asterisks indicate the ΔrcnA samples are significantly different from the wild type strain (p < 0.05).
Mentions: To have more information about the function of some of the genes identified as more expressed in the A. fumigatus wild type and repressed in the ΔAfcrzA, we inactivated the AfrcnA (Afu2g13060), AfrfeF (Afu4g10200), Af BAR adaptor protein (Afu3g14230), and A. fumigatus phospholipase D (Afu2g16520). Since calcium is involved in different kinds of stresses, such as oxidative stress and uncontrolled proliferation and survival [38-44], we decided to determine if several different culture conditions could affect the growth of these deletion strains. Except for ΔAfrcnA, the deletion mutants showed comparable growth phenotypes to the wild type strain in the presence of the following agents or stressing situations: oxidizing agents and metals (paraquat, t-butyl hydroperoxide, zinc, iron, and chromium), calcium, cyclosporine A, DNA damaging agents (4-nitroquinoline oxide, hydroxyurea, camptothecin, and bleomycin), and temperature (30, 37, and 44°C) (data not shown). However, ΔAfrcnA growth was less sensitive to menadione 30 μM, hydrogen peroxide 2.5 mM, EGTA 25 mM, and MnCl2 25 mM (Figure 4B). We exposed both wild type and ΔAfrcnA strains for 200 mM calcium chloride for 10 minutes and measured the calcineurin activity in these strains (Figure 4C). In the wild type strain, there is about 50% increase in the calcineurin activity when the mycelia was exposed to calcium chloride 200 mM for 10 minutes (Figure 4C). However, in the ΔAfrcnA mutant strain there is a significant increase in the calcineurin activity at 0 and 10 minutes in the presence of calcium chloride (Figure 4C). These results suggest that AfRcnA has an inhibitory effect on calcineurin activity when A. fumigatus is exposed to high calcium concentrations.

Bottom Line: GFP::RcnA was mostly detected along the germling, did not accumulate in the nuclei and its location is not affected by the cellular response to calcium chloride.AfRcnA, one of these selected genes, encodes a modulator of calcineurin activity.A. nidulans AnRcnA mutation is suppressing CnaA mutation and it is responsible for modulating the calcineurin activity and mRNA accumulation of genes encoding calcium transporters.

View Article: PubMed Central - HTML - PubMed

Affiliation: Centro de Ciência e Tecnologia do Bioetanol and Faculdade de Ciências Farmacêuticas de Ribeirão Preto Universidade de São Paulo, São Paulo, Ribeirão Preto 14040-903, Brazil.

ABSTRACT

Background: Calcineurin, a serine/threonine-specific protein phosphatase, plays an important role in the control of cell morphology and virulence in fungi. Calcineurin regulates localization and activity of a transcription factor called CRZ1. Recently, we characterize Aspergillus fumigatus CRZ1 homologue, AfCrzA. Here, we investigate which pathways are influenced by A. fumigatus AfCrzA during a short pulse of calcium by comparatively determining the transcriptional profile of A. fumigatus wild type and DeltaAfcrzA mutant strains.

Results: We were able to observe 3,622 genes modulated in at least one timepoint in the mutant when compared to the wild type strain (3,211 and 411 at 10 and 30 minutes, respectively). Decreased mRNA abundance in the DeltacrzA was seen for genes encoding calcium transporters, transcription factors and genes that could be directly or indirectly involved in calcium metabolism. Increased mRNA accumulation was observed for some genes encoding proteins involved in stress response. AfCrzA overexpression in A. fumigatus increases the expression of several of these genes. The deleted strain of one of these genes, AfRcnA, belonging to a class of endogenous calcineurin regulators, calcipressins, had more calcineurin activity after exposure to calcium and was less sensitive to menadione 30 microM, hydrogen peroxide 2.5 mM, EGTA 25 mM, and MnCl2 25 mM. We constructed deletion, overexpression, and GFP fusion protein for the closely related A. nidulans AnRcnA. GFP::RcnA was mostly detected along the germling, did not accumulate in the nuclei and its location is not affected by the cellular response to calcium chloride.

Conclusion: We have performed a transcriptional profiling analysis of the A. fumigatus DeltaAfcrzA mutant strain exposed to calcium stress. This provided an excellent opportunity to identify genes and pathways that are under the influence of AfCrzA. AfRcnA, one of these selected genes, encodes a modulator of calcineurin activity. Concomitantly with A. fumigatus AfrcnA molecular analysis, we decided to exploit the conserved features of A. nidulans calcineurin system and investigated the A. nidulans AnRcnA homologue. A. nidulans AnRcnA mutation is suppressing CnaA mutation and it is responsible for modulating the calcineurin activity and mRNA accumulation of genes encoding calcium transporters.

Show MeSH
Related in: MedlinePlus