Complete Genome Sequence of Streptomyces lavendulae subsp. lavendulae CCM 3239 (Formerly “Streptomyces aureofaciens CCM 3239”), a Producer of the Angucycline-Type Antibiotic Auricin

Busche T, Novakova R, Al'Dilaimi A, et al. Complete Genome Sequence of Streptomyces lavendulae subsp. lavendulae CCM 3239 (Formerly “Streptomyces aureofaciens CCM 3239”), a Producer of the Angucycline-Type Antibiotic Auricin. Genome Announcements. 2018;6(9): e00103-18.Streptomyces lavendulae subsp. lavendulae CCM 3239 produces the angucycline antibiotic auricin and was thought to be the type strain of Streptomyces aureofaciens. We report the complete genome sequence of this strain, which consists of a linear chromosome and the linear plasmid pSA3239, and demonstrate it to be S. lavendulae subsp. lavendulae

The dpsA Gene of Streptomyces coelicolor: Induction of Expression from a Single Promoter in Response to Environmental Stress or during Development

The DpsA protein plays a dual role in Streptomyces coelicolor, both as part of the stress response and contributing to nucleoid condensation during sporulation. Promoter mapping experiments indicated that dpsA is transcribed from a single, sigB-like dependent promoter. Expression studies implicate SigH and SigB as the sigma factors responsible for dpsA expression while the contribution of other SigB-like factors is indirect by means of controlling sigH expression. The promoter is massively induced in response to osmotic stress, in part due to its sensitivity to changes in DNA supercoiling. In addition, we determined that WhiB is required for dpsA expression, particularly during development. Gel retardation experiments revealed direct interaction between apoWhiB and the dpsA promoter region, providing the first evidence for a direct WhiB target in S. coelicolor

The Anti-Anti-Sigma Factor BldG Is Involved in Activation of the Stress Response Sigma Factor σH in Streptomyces coelicolor A3(2) ▿

The alternative stress response sigma factor σH has a role in regulation of the osmotic stress response and in morphological differentiation in Streptomyces coelicolor A3(2). Its gene, sigH, is located in an operon with the gene that encodes its anti-sigma factor UshX (PrsH). However, no gene with similarity to an anti-anti-sigma factor which may have a role in σH activation by a “partner-switching” mechanism is located in the operon. By using a combination of several approaches, including pull-down and bacterial two-hybrid assays and visualization of the complex by native polyacrylamide electrophoresis, we demonstrated a direct interaction between UshX and the pleiotropic sporulation-specific anti-anti-sigma factor BldG. Osmotic induction of transcription of the sigHp2 promoter that is specifically recognized by RNA polymerase containing σH was absent in an S. coelicolor bldG mutant, indicating a role of BldG in σH activation by a partner-switching-like mechanism

Cross-Recognition of Promoters by the Nine SigB Homologues Present in Streptomyces coelicolor A3(2)

In contrast to Bacillus subtilis, Streptomyces coelicolor A3(2) contains nine homologues of stress response sigma factor SigB with a major role in differentiation and osmotic stress response. The aim of this study was to further characterize these SigB homologues. We previously established a two-plasmid system to identify promoters recognized by sigma factors and used it to identify promoters recognized by the three SigB homologues, SigF, SigG, and SigH from S. coelicolor A3(2). Here, we used this system to identify 14 promoters recognized by SigB. The promoters were verified in vivo in S. coelicolor A3(2) under osmotic stress conditions in sigB and sigH operon mutants, indicating some cross-recognition of these promoters by these two SigB homologues. This two-plasmid system was used to examine the recognition of all identified SigB-, SigF-, SigG-, and SigH-dependent promoters with all nine SigB homologues. The results confirmed this cross-recognition. Almost all 24 investigated promoters were recognized by two or more SigB homologues and data suggested some distinguishing groups of promoters recognized by these sigma factors. However, analysis of the promoters did not reveal any specific sequence characteristics for these recognition groups. All promoters showed high similarity in the -35 and -10 regions. Immunoblot analysis revealed the presence of SigB under osmotic stress conditions and SigH during morphological differentiation. Together with the phenotypic analysis of sigB and sigH operon mutants in S. coelicolor A3(2), the results suggest a dominant role for SigB in the osmotic stress response and a dual role for SigH in the osmotic stress response and morphological differentiation. These data suggest a complex regulation of the osmotic stress response in relation to morphological differentiation in S. coelicolor A3(2)

The linear plasmid pSA3239 is essential for the replication of the Streptomyces lavendulae subsp. lavendulae CCM 3239 chromosome.

Novakova R, Rückert C, Knirschova R, et al. The linear plasmid pSA3239 is essential for the replication of the Streptomyces lavendulae subsp. lavendulae CCM 3239 chromosome. Research in microbiology. 2021: 103870.We previously reported the complete genome of Streptomyces lavendulae subsp. lavendulae CCM 3239, containing the linear chromosome and the large linear plasmid pSA3239. Although the chromosome exhibited replication features characteristic for the archetypal end-patching replication, it lacked the tap/tpg gene pair for two proteins essential for this process. However, this archetypal tpgSa-tapSa operon is present in pSA3239. Complete genomic sequence of the S. lavendulae Del-LP strain lacking this plasmid revealed the circularization of its chromosome with a large deletion of both arms. These results suggest an essential role of pSA3239-encoded TapSa/TpgSa in the end-patching replication of the chromosome. Copyright © 2021 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved

Bacterial strains, plasmids and cosmids.

a<p>Access <a href="http://strepdb.streptomyces.org.uk/" target="_blank">http://strepdb.streptomyces.org.uk/</a> for information about transposon insertion details.</p

Increasing concentrations of apoWhiB causes electrophoretic shift of <i>dpsAp</i> region.

<p>A double-stranded oligonucleotide containing the OctA2 binding site was used as negative control (<b>A</b>). qRT PCR monitoring <i>dpsA</i> expression levels in <i>S. coelicolor</i> M145 and <i>whiB</i> mutant in response to osmotic stress (<b>B</b>) and heat stress (<b>C</b>). Significant differences in <i>dpsA</i> expression levels (One way Anova, P<0.05) were detected between <i>S. coelicolor</i> M145 and <i>whiB</i>⁻ strain after 1 hour of osmotic stress (*). Error bars indicate standard deviation.</p

Model depicting the regulatory network controlling <i>dpsA</i> expression.

<p>Only stress induced elements are shown. Solid lines indicate experimentally verified relationships (direct and indirect) while the dotted line indicates a partially verified one.</p