The transcriptomic fingerprint of glucoamylase over-expression in Aspergillus niger

dc.contributor.authorKwon, Min Jinen
dc.contributor.authorJørgensen, Thomas R.en
dc.contributor.authorNitsche, Benjamin M.en
dc.contributor.authorArentshorst, Marken
dc.contributor.authorPark, Joohaeen
dc.contributor.authorRam, Arthur F. J.en
dc.contributor.authorMeyer, Veraen
dc.date.accessioned2015-11-21T00:59:12Z
dc.date.available2015-08-11T12:00:00Z
dc.date.issued2012
dc.date.submitted2015-08-10
dc.description.abstractBackground: Filamentous fungi such as Aspergillus niger are well known for their exceptionally high capacity for secretion of proteins, organic acids, and secondary metabolites and they are therefore used in biotechnology as versatile microbial production platforms. However, system-wide insights into their metabolic and secretory capacities are sparse and rational strain improvement approaches are therefore limited. In order to gain a genome-wide view on the transcriptional regulation of the protein secretory pathway of A. niger, we investigated the transcriptome of A. niger when it was forced to overexpression the glaA gene (encoding glucoamylase, GlaA) and secrete GlaA to high level. Results: An A. niger wild-type strain and a GlaA over-expressing strain, containing multiple copies of the glaA gene, were cultivated under maltose-limited chemostat conditions (specific growth rate 0.1 h-1). Elevated glaA mRNA and extracellular GlaA levels in the over-expressing strain were accompanied by elevated transcript levels from 772 genes and lowered transcript levels from 815 genes when compared to the wild-type strain. Using GO term enrichment analysis, four higher-order categories were identified in the up-regulated gene set: i) endoplasmic reticulum (ER) membrane translocation, ii) protein glycosylation, iii) vesicle transport, and iv) ion homeostasis. Among these, about 130 genes had predicted functions for the passage of proteins through the ER and those genes included target genes of the HacA transcription factor that mediates the unfolded protein response (UPR), e.g. bipA, clxA, prpA, tigA and pdiA. In order to identify those genes that are important for high-level secretion of proteins by A. niger, we compared the transcriptome of the GlaA overexpression strain of A. niger with six other relevant transcriptomes of A. niger. Overall, 40 genes were found to have either elevated (from 36 genes) or lowered (from 4 genes) transcript levels under all conditions that were examined, thus defining the core set of genes important for ensuring high protein traffic through the secretory pathway. Conclusion: We have defined the A. niger genes that respond to elevated secretion of GlaA and, furthermore, we have defined a core set of genes that appear to be involved more generally in the intensified traffic of proteins through the secretory pathway of A. niger. The consistent up-regulation of a gene encoding the acetyl-coenzyme A transporter suggests a possible role for transient acetylation to ensure correct folding of secreted proteins.en
dc.identifier.eissn1471-2164
dc.identifier.uriurn:nbn:de:kobv:83-opus4-70370
dc.identifier.urihttps://depositonce.tu-berlin.de/handle/11303/4925
dc.identifier.urihttp://dx.doi.org/10.14279/depositonce-4628
dc.languageEnglishen
dc.language.isoenen
dc.rights.urihttps://creativecommons.org/licenses/by/2.0/en
dc.subject.ddc570 Biowissenschaften; Biologieen
dc.subject.ddc610 Medizin und Gesundheiten
dc.subject.otherAspergillus nigeren
dc.subject.otherendoplasmic reticulumen
dc.subject.otherglucoamylaseen
dc.subject.otherHacAen
dc.subject.otherprotein expressionen
dc.subject.othersecretionen
dc.subject.othertranscriptomeen
dc.subject.otherunfolded protein responseen
dc.titleThe transcriptomic fingerprint of glucoamylase over-expression in Aspergillus nigeren
dc.typeArticleen
dc.type.versionpublishedVersionen
dcterms.bibliographicCitation.articlenumber701en
dcterms.bibliographicCitation.doi10.1186/1471-2164-13-701en
dcterms.bibliographicCitation.journaltitleBMC Genomicsen
dcterms.bibliographicCitation.originalpublishernameBioMed Centralen
dcterms.bibliographicCitation.originalpublisherplaceLondonen
dcterms.bibliographicCitation.volume13en
tub.accessrights.dnbfree*
tub.affiliationFak. 3 Prozesswissenschaften::Inst. Biotechnologie::FG Angewandte und Molekulare Mikrobiologiede
tub.affiliation.facultyFak. 3 Prozesswissenschaftende
tub.affiliation.groupFG Angewandte und Molekulare Mikrobiologiede
tub.affiliation.instituteInst. Biotechnologiede
tub.identifier.opus47037
tub.publisher.universityorinstitutionTechnische Universität Berlinen

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