Limits...
The transcriptome of lae1 mutants of Trichoderma reesei cultivated at constant growth rates reveals new targets of LAE1 function.

Fekete E, Karaffa L, Karimi Aghcheh R, Németh Z, Fekete E, Orosz A, Paholcsek M, Stágel A, Kubicek CP - BMC Genomics (2014)

Bottom Line: The effect on the expression of some gene categories identified earlier (polyketide synthases, heterokaryon incompatibility proteins, PTH11-receptors) was confirmed, but in addition GCN5-N-acetyltransferases, amino acid permeases and flavin monooxygenases were identified as so far unknown major targets of LAE1 action.About a tenth of the genes differentially expressed in the Δlae1 mutant under either growth condition were found to be clustered in the genome, but no specific gene group was associated with this phenomenon.Our data show that - using T. reesei LAE1 as a model - the investigation of transcriptome in regulatory mutants at constant growth rates leads to new insights into the physiological roles of the respective regulator.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemical Engineering, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary. karaffa.levente@science.unideb.hu.

ABSTRACT

Background: The putative methyltransferase LaeA is a global regulator that affects the expression of multiple secondary metabolite gene clusters in several fungi. In Trichoderma reesei, its ortholog LAE1 appears to predominantly regulate genes involved in increasing competitive fitness in its environment, including expression of cellulases and polysaccharide hydrolases. A drawback in all studies related to LaeA/LAE1 function so far, however, is that the respective loss-of-function and overexpressing mutants display different growth rates. Thus some of the properties attributed to LaeA/LAE1 could be simply due to changes of the growth rate.

Results: We cultivated T. reesei, a Δlae1 mutant and a lae1-overexpressing strain in chemostats on glucose at two different growth rates (0.075 and 0.020 h-1) which resemble growth rates at repressing and derepressing conditions, respectively. Under these conditions, the effect of modulating LAE1 expression was mainly visible in the Δlae1 mutant, whereas the overexpressing strain showed little differences to the parent strain. The effect on the expression of some gene categories identified earlier (polyketide synthases, heterokaryon incompatibility proteins, PTH11-receptors) was confirmed, but in addition GCN5-N-acetyltransferases, amino acid permeases and flavin monooxygenases were identified as so far unknown major targets of LAE1 action. LAE1 was also shown to interfere with the regulation of expression of several genes by the growth rate. About a tenth of the genes differentially expressed in the Δlae1 mutant under either growth condition were found to be clustered in the genome, but no specific gene group was associated with this phenomenon.

Conclusions: Our data show that - using T. reesei LAE1 as a model - the investigation of transcriptome in regulatory mutants at constant growth rates leads to new insights into the physiological roles of the respective regulator.

Show MeSH

Related in: MedlinePlus

Expression of genes belonging to metabolism-related FunCat groups inT. reesei Δlae1(ΔLAE1) andT. reesei OElae1(OElae1) during cultivation at 0.075 (HG) and 0.02 (LG) h-1, respectively. “Up” means 2-fold upregulation, “down” 2-fold downregulation when compared to T. reesei QM9414 (WT). FunCat categories shown are: 01.01, amino acid metabolism; 01.03, nucleotide metabolism; 01.05, carbohydrate metabolism; 01.06, lipid metabolism; 01.25.01, extracellular carbohydrate degradation; 01.25.03, extracellular protein degradation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC4061448&req=5

Fig2: Expression of genes belonging to metabolism-related FunCat groups inT. reesei Δlae1(ΔLAE1) andT. reesei OElae1(OElae1) during cultivation at 0.075 (HG) and 0.02 (LG) h-1, respectively. “Up” means 2-fold upregulation, “down” 2-fold downregulation when compared to T. reesei QM9414 (WT). FunCat categories shown are: 01.01, amino acid metabolism; 01.03, nucleotide metabolism; 01.05, carbohydrate metabolism; 01.06, lipid metabolism; 01.25.01, extracellular carbohydrate degradation; 01.25.03, extracellular protein degradation.

Mentions: In addition, LAE1-effected genes involved in metabolism were found to have a strong bias towards amino acid metabolism at the high growth rate, with the majority of them being downregulated (Figure 2). No significant changes in the expression of genes involved in intermediary metabolism (carbohydrate, lipid, amino acid and nucleotide metabolism) were noted at the low growth rate.Table 2


The transcriptome of lae1 mutants of Trichoderma reesei cultivated at constant growth rates reveals new targets of LAE1 function.

Fekete E, Karaffa L, Karimi Aghcheh R, Németh Z, Fekete E, Orosz A, Paholcsek M, Stágel A, Kubicek CP - BMC Genomics (2014)

Expression of genes belonging to metabolism-related FunCat groups inT. reesei Δlae1(ΔLAE1) andT. reesei OElae1(OElae1) during cultivation at 0.075 (HG) and 0.02 (LG) h-1, respectively. “Up” means 2-fold upregulation, “down” 2-fold downregulation when compared to T. reesei QM9414 (WT). FunCat categories shown are: 01.01, amino acid metabolism; 01.03, nucleotide metabolism; 01.05, carbohydrate metabolism; 01.06, lipid metabolism; 01.25.01, extracellular carbohydrate degradation; 01.25.03, extracellular protein degradation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4061448&req=5

Fig2: Expression of genes belonging to metabolism-related FunCat groups inT. reesei Δlae1(ΔLAE1) andT. reesei OElae1(OElae1) during cultivation at 0.075 (HG) and 0.02 (LG) h-1, respectively. “Up” means 2-fold upregulation, “down” 2-fold downregulation when compared to T. reesei QM9414 (WT). FunCat categories shown are: 01.01, amino acid metabolism; 01.03, nucleotide metabolism; 01.05, carbohydrate metabolism; 01.06, lipid metabolism; 01.25.01, extracellular carbohydrate degradation; 01.25.03, extracellular protein degradation.
Mentions: In addition, LAE1-effected genes involved in metabolism were found to have a strong bias towards amino acid metabolism at the high growth rate, with the majority of them being downregulated (Figure 2). No significant changes in the expression of genes involved in intermediary metabolism (carbohydrate, lipid, amino acid and nucleotide metabolism) were noted at the low growth rate.Table 2

Bottom Line: The effect on the expression of some gene categories identified earlier (polyketide synthases, heterokaryon incompatibility proteins, PTH11-receptors) was confirmed, but in addition GCN5-N-acetyltransferases, amino acid permeases and flavin monooxygenases were identified as so far unknown major targets of LAE1 action.About a tenth of the genes differentially expressed in the Δlae1 mutant under either growth condition were found to be clustered in the genome, but no specific gene group was associated with this phenomenon.Our data show that - using T. reesei LAE1 as a model - the investigation of transcriptome in regulatory mutants at constant growth rates leads to new insights into the physiological roles of the respective regulator.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemical Engineering, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary. karaffa.levente@science.unideb.hu.

ABSTRACT

Background: The putative methyltransferase LaeA is a global regulator that affects the expression of multiple secondary metabolite gene clusters in several fungi. In Trichoderma reesei, its ortholog LAE1 appears to predominantly regulate genes involved in increasing competitive fitness in its environment, including expression of cellulases and polysaccharide hydrolases. A drawback in all studies related to LaeA/LAE1 function so far, however, is that the respective loss-of-function and overexpressing mutants display different growth rates. Thus some of the properties attributed to LaeA/LAE1 could be simply due to changes of the growth rate.

Results: We cultivated T. reesei, a Δlae1 mutant and a lae1-overexpressing strain in chemostats on glucose at two different growth rates (0.075 and 0.020 h-1) which resemble growth rates at repressing and derepressing conditions, respectively. Under these conditions, the effect of modulating LAE1 expression was mainly visible in the Δlae1 mutant, whereas the overexpressing strain showed little differences to the parent strain. The effect on the expression of some gene categories identified earlier (polyketide synthases, heterokaryon incompatibility proteins, PTH11-receptors) was confirmed, but in addition GCN5-N-acetyltransferases, amino acid permeases and flavin monooxygenases were identified as so far unknown major targets of LAE1 action. LAE1 was also shown to interfere with the regulation of expression of several genes by the growth rate. About a tenth of the genes differentially expressed in the Δlae1 mutant under either growth condition were found to be clustered in the genome, but no specific gene group was associated with this phenomenon.

Conclusions: Our data show that - using T. reesei LAE1 as a model - the investigation of transcriptome in regulatory mutants at constant growth rates leads to new insights into the physiological roles of the respective regulator.

Show MeSH
Related in: MedlinePlus