title: Comparative transcriptional analysis of Bacillus subtilis cells overproducing either secreted proteins, lipoproteins or membrane proteins.
abstract: BACKGROUND
  Bacillus subtilis is a favorable host for the production of industrially relevant proteins because of its capacity of secreting proteins into the medium to high levels, its GRAS (Generally Recognized As Safe) status, its genetic accessibility and its capacity to grow in large fermentations. However, production of heterologous proteins still faces limitations.
  
  
  RESULTS
  This study aimed at the identification of bottlenecks in secretory protein production by analyzing the response of B. subtilis at the transcriptome level to overproduction of eight secretory proteins of endogenous and heterologous origin and with different subcellular or extracellular destination: secreted proteins (NprE and XynA of B. subtilis, Usp45 of Lactococcus lactis, TEM-1 β-lactamase of Escherichia coli), membrane proteins (LmrA of L. lactis and XylP of Lactobacillus pentosus) and lipoproteins (MntA and YcdH of B. subtilis). Responses specific for proteins with a common localization as well as more general stress responses were observed. The latter include upregulation of genes encoding intracellular stress proteins (groES/EL, CtsR regulated genes). Specific responses include upregulation of the liaIHGFSR operon under Usp45 and TEM-1 β-lactamase overproduction; cssRS, htrA and htrB under all secreted proteins overproduction; sigW and SigW-regulated genes mainly under membrane proteins overproduction; and ykrL (encoding an HtpX homologue) specifically under membrane proteins overproduction.
  
  
  CONCLUSIONS
  The results give better insights into B. subtilis responses to protein overproduction stress and provide potential targets for genetic engineering in order to further improve B. subtilis as a protein production host.
authors.affiliation: Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands.
authors.forename: Bogumiła C
authors.initials: BC
authors.lastname: Marciniak
authors.forename: Hein
authors.initials: H
authors.lastname: Trip
authors.forename: Patricia J
authors.initials: PJ
authors.lastname: van-der Veek
authors.forename: Oscar P
authors.initials: OP
authors.lastname: Kuipers
mesh_terms: D001412:Bacillus subtilis / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D015536:Down-Regulation; D008074:Lipoproteins / Q000235:genetics / Q000378:metabolism*; D008563:Membrane Lipids / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism; D059467:Transcriptome; D015854:Up-Regulation
chemical_list: D001426:Bacterial Proteins; C490532:LiaRS protein, Bacillus subtilis; D008074:Lipoproteins; D008563:Membrane Lipids; D008565:Membrane Proteins; D011994:Recombinant Proteins; C413458:SigW protein, Bacillus subtilis; D012808:Sigma Factor