Lack of A-factor Production Induces the Expression of Nutrient Scavenging and Stress-related Proteins in Streptomyces griseus>

Abstract

The small ␥-butyrolactone A-factor is an important autoregulatory signaling molecule for the soil-inhabiting streptomycetes. Starvation is a major trigger for development, and nutrients are provided by degradation of the vegetative mycelium via a process of programmed cell death, reusing proteins, nucleic acids, and cell wall material. The A-factor regulon includes many extracellular hydrolases. Here we show via proteomics analysis that many nutrientscavenging and stress-related proteins were overexpressed in an A-factor non-producing mutant of Streptomyces griseus B-2682. Transcript analysis showed that this is primarily due to differential transcription of the target genes during early development. The targets include proteins relating to nutrient stress and environmental stress and an orthologue of the Bacillus sporulation control protein Spo0M. The enhanced expression of these proteins underlines the stress that is generated by the absence of A-factor. Wild-type developmental gene expression was restored to the A-factor non-producing mutant by the signaling protein Factor C in line with our earlier observation that Factor C triggers A-factor production.

Mutation in <b><i>afsR</i></b> Leads to A-Factor Deficiency in <b><i>Streptomyces griseus</i></b> B2682

“…The nondifferentiating phenotype of AFN could be restored by exogenously added A-factor or by introducing the facC gene to AFN, which is responsible for the synthesis of factor C, which is an autoregulatory protein essential for the induction of differentiation in S. albidoflavus (formerly known as S. griseus 45H) [Birkó et al, 2007[Birkó et al, , 2009; Kiss et al, 2008]. These observations suggest that all the genes that function in the mode of action or in the biosynthesis of A-factor -including AfsA -are functional in AFN [Birkó et al, 2007[Birkó et al, , 2009. The fact that AFN harbors a mutation in the afsR gene suggests that this mutation might be responsible for the bald phenotype of AFN and raises the possible role of AfsR in the regulation of Afactor biosynthesis.…”

“…The strains used in this study were S. griseus NRRL B2682 (wild-type parental strain, in short B2682) and its spontaneous AFN bald mutant S. griseus NRRL B2682-AFN (in short AFN) [Birkó et al, 2007[Birkó et al, , 2009. The following strains were created in this study: S. griseus NRRL B2682 pHJL401 (in short B2682pH), S. griseus NRRL B2682 pHJL401-afsR (in short B2682pHR), S. griseus NRRL B2682-AFN pHJL401 (in short AFNpH), and S. griseus B2682-AFN pHJL401-afsR (in short AFNpHR).…”

Functional Analysis of the N-Acetylglucosamine Metabolic Genes of Streptomyces coelicolor and Role in Control of Development and Antibiotic Production

“…Samples were taken before induction and 30 min after induction. RNA isolation and semiquantitative reverse transcription-PCR (RT-PCR) were carried out twice as described previously (4). Two hundred nanograms of RNA was used in each reaction mix (concentration was assessed using a Nanodrop spectrophotometer).…”

“…GH20-type hexosaminidases are involved in hydrolysis of the extracellular polysaccharide matrix in bacteria, such as ␤-1,6-linkages of PGA [poly-beta-(1,6)-N-acetylglucosamine], and do not play a role in central metabolism. The nearest functional homologue of the NagB gene is SCO2786, which encodes the endo-␤-N-acetylhexosaminidase Hex (23% aa identity) and was shown to cleave the GlcNAc oligomers (GlcNAc) 3 and (GlcNAc) 4 in Streptomyces plicatus (24). Based on this in silico analysis, we concluded that in S. coelicolor, PTS-transported GlcNAc-6P is metabolized solely by the gene products of open reading frames (ORFs) SCO4284 (nagA) and SCO5236 (nagB).…”

Identification of β-lactamases in human and bovine isolates of Staphylococcus aureus strains having borderline resistance to penicillinase-resistant penicillins (PRPs) with proteomic methods

“…The parameters used for the database search identical to those described by Birkó et al (Birkó et al, 2009). Protein lists were revised manually taking into consideration only the significant peptide hits (p<0.05), minimum two significant peptides/protein.…”