scholarly journals Cloning, disruption, and transcriptional analysis of three RNA polymerase sigma factor genes of Streptomyces coelicolor A3(2).

1990 ◽  
Vol 172 (6) ◽  
pp. 3367-3378 ◽  
Author(s):  
M J Buttner ◽  
K F Chater ◽  
M J Bibb
Keyword(s):  
Rna Polymerase ◽  
Sigma Factor ◽  
Streptomyces Coelicolor ◽  
Transcriptional Analysis

scholarly journals ςBldN, an Extracytoplasmic Function RNA Polymerase Sigma Factor Required for Aerial Mycelium Formation in Streptomyces coelicolor A3(2)

2000 ◽  
Vol 182 (16) ◽  
pp. 4606-4616 ◽  
Author(s):  
Maureen J. Bibb ◽  
Virginie Molle ◽  
Mark J. Buttner
Keyword(s):  
Rna Polymerase ◽  
Sigma Factor ◽  
Streptomyces Coelicolor ◽  
Aerial Mycelium ◽  
Sigma Factors ◽  
Colony Development ◽  
Null Mutant ◽  
Wild Type

ABSTRACT Sporulation mutants of Streptomyces coelicolor appear white because they are defective in the synthesis of the gray polyketide spore pigment, and such white (whi) mutants have been used to define 13 sporulation loci. whiN, one of five new whi loci identified in a recent screen of NTG (N-methyl-N′-nitro-N-nitrosoguanidine)-inducedwhi strains (N. J. Ryding et al., J. Bacteriol. 181:5419–5425, 1999), was defined by two mutants, R112 and R650. R650 produced frequent spores that were longer than those of the wild type. In contrast, R112 produced long, straight, undifferentiated hyphae, although rare spore chains were observed, sometimes showing highly irregular septum placement. Subcloning and sequencing showed thatwhiN encodes a member of the extracytoplasmic function subfamily of RNA polymerase sigma factors and that the sigma factor has an unusual N-terminal extension of approximately 86 residues that is not present in other sigma factors. A constructed whiN null mutant failed to form aerial mycelium (the “bald” phenotype) and, as a consequence, whiN was renamed bldN. This observation was not totally unexpected because, on some media, the R112 point mutant produced substantially less aerial mycelium than its parent, M145. The bldN null mutant did not fit simply into the extracellular signaling cascade proposed for S. coelicolor bld mutants. Expression of bldN was analyzed during colony development in wild-type and aerial mycelium-deficientbld strains. bldN was transcribed from a single promoter, bldNp. bldN transcription was developmentally regulated, commencing approximately at the time of aerial mycelium formation, and depended on bldG and bldH, but not on bldA, bldB, bldC,bldF, bldK, or bldJ or onbldN itself. Transcription from the p1 promoter of the response-regulator gene bldM depended onbldN in vivo, and the bldMp1 promoter was shown to be a direct biochemical target for ςBldN holoenzyme in vitro.

scholarly journals RNA Polymerase Sigma Factor That Blocks Morphological Differentiation by Streptomyces coelicolor

2001 ◽  
Vol 183 (20) ◽  
pp. 5991-5996 ◽  
Author(s):  
Amy M. Gehring ◽  
Narie J. Yoo ◽  
Richard Losick
Keyword(s):  
Rna Polymerase ◽  
Sigma Factor ◽  
Insertional Mutagenesis ◽  
Early Stage ◽  
Streptomyces Coelicolor ◽  
Morphological Differentiation ◽  
Aerial Mycelium ◽  
Growth Defect ◽  
Insertion Mutant

ABSTRACT The filamentous bacterium Streptomyces coelicolorundergoes a complicated process of morphological differentiation that begins with the formation of an aerial mycelium and culminates in sporulation. Genes required for the initiation of aerial mycelium formation have been termed bld (bald), describing the smooth, undifferentiated colonies of mutant strains. By using an insertional mutagenesis protocol that relies on in vitro transposition, we have isolated a bld mutant harboring an insertion in a previously uncharacterized gene, SCE59.12c, renamed here rsuA. The insertion mutant exhibited no measurable growth defect but failed to produce an aerial mycelium and showed a significant delay in the production of the polyketide antibiotic actinorhodin. The rsuA gene encodes an apparent anti-sigma factor and is located immediately downstream ofSCE59.13c, renamed here sigU, whose product is inferred to be a member of the extracytoplasmic function subfamily of RNA polymerase sigma factors. The absence ofrsuA in a strain that contained sigUcaused a block in development, and the overexpression ofsigU in an otherwise wild-type strain caused a delay in aerial mycelium formation. However, a strain in which bothrsuA and sigU had been deleted was able to undergo morphological differentiation normally. We conclude that thersuA-encoded anti-sigma factor is responsible for antagonizing the function of the sigma factor encoded bysigU. We also conclude that thesigU-encoded sigma factor is not normally required for development but that its uncontrolled activity obstructs morphological differentiation at an early stage.

scholarly journals Evidence that the Extracytoplasmic Function Sigma Factor ςE Is Required for Normal Cell Wall Structure in Streptomyces coelicolor A3(2)

1999 ◽  
Vol 181 (1) ◽  
pp. 204-211 ◽  
Author(s):  
Mark S. B. Paget ◽  
Leony Chamberlin ◽  
Abdelmadjid Atrih ◽  
Simon J. Foster ◽  
Mark J. Buttner
Keyword(s):  
Cell Wall ◽  
Rna Polymerase ◽  
Sigma Factor ◽  
Normal Cell ◽  
Streptomyces Coelicolor ◽  
Normal Growth ◽  
Cell Wall Structure ◽  
Wall Structure ◽  
Dependent Manner

ABSTRACT The sigE gene of Streptomyces coelicolorA3(2) encodes an RNA polymerase sigma factor belonging to the extracytoplasmic function (ECF) subfamily. Constructed sigEdeletion and disruption mutants were more sensitive than the parent to muramidases such as hen egg white lysozyme and to the CwlA amidase fromBacillus subtilis. This correlated with an altered muropeptide profile, as determined by reverse-phase high-performance liquid chromatography analysis of lytic digests of purified peptidoglycan. The sigE mutants required high levels of magnesium for normal growth and sporulation, overproducing the antibiotic actinorhodin and forming crenellated colonies in its absence. Together, these data suggest that sigE is required for normal cell wall structure. The role of ςE was further investigated by analyzing the expression of hrdD, which is partially sigE dependent. The hrdDgene, which encodes the ςHrdD subunit of RNA polymerase, is transcribed from two promoters, hrdDp 1 andhrdDp 2, both similar to promoters recognized by other ECF sigma factors. The activities ofhrdDp 1 and hrdDp 2 were reduced 20- and 3-fold, respectively, in sigE mutants, although only hrdDp 1 was recognized by EςE in vitro. Growth on media deficient in magnesium caused the induction of both hrdD promoters in asigE-dependent manner.

scholarly journals Regulation of Sporangium Formation by BldD in the Rare Actinomycete Actinoplanes missouriensis

2017 ◽  
Vol 199 (12) ◽  
Author(s):  
Yoshihiro Mouri ◽  
Kenji Konishi ◽  
Azusa Fujita ◽  
Takeaki Tezuka ◽  
Yasuo Ohnishi
Keyword(s):  
Vegetative Growth ◽  
Streptomyces Coelicolor ◽  
Morphological Differentiation ◽  
Transcriptional Regulator ◽  
Saccharopolyspora Erythraea ◽  
Transcriptional Analysis ◽  
Morphological Development ◽  
Sequencing Analysis ◽  
Content Type ◽  
Biological Studies

ABSTRACT The rare actinomycete Actinoplanes missouriensis forms sporangia, including hundreds of flagellated spores that start swimming as zoospores after their release. Under conditions suitable for vegetative growth, zoospores stop swimming and germinate. A comparative proteome analysis between zoospores and germinating cells identified 15 proteins that were produced in larger amounts in germinating cells. They include an orthologue of BldD (herein named AmBldD [BldD of A. missouriensis]), which is a transcriptional regulator involved in morphological development and secondary metabolism in Streptomyces. AmBldD was detected in mycelia during vegetative growth but was barely detected in mycelia during the sporangium-forming phase, in spite of the constant transcription of AmbldD throughout growth. An AmbldD mutant started to form sporangia much earlier than the wild-type strain, and the resulting sporangia were morphologically abnormal. Recombinant AmBldD bound a palindromic sequence, the AmBldD box, located upstream from AmbldD. 3′,5′-Cyclic di-GMP significantly enhanced the in vitro DNA-binding ability of AmBldD. A chromatin immunoprecipitation-sequencing analysis and an in silico search for AmBldD boxes revealed that AmBldD bound 346 genomic loci that contained the 19-bp inverted repeat 5′-NN(G/A)TNACN(C/G)N(G/C)NGTNA(C/T)NN-3′ as the consensus AmBldD-binding sequence. The transcriptional analysis of 27 selected AmBldD target gene candidates indicated that AmBldD should repress 12 of the 27 genes, including bldM, ssgB, whiD, ddbA, and wblA orthologues. These genes are involved in morphological development in Streptomyces coelicolor A3(2). Thus, AmBldD is a global transcriptional regulator that seems to repress the transcription of tens of genes during vegetative growth, some of which are likely to be required for sporangium formation. IMPORTANCE The rare actinomycete Actinoplanes missouriensis undergoes complex morphological differentiation, including sporangium formation. However, almost no molecular biological studies have been conducted on this bacterium. BldD is a key global regulator involved in the morphological development of streptomycetes. BldD orthologues are highly conserved among sporulating actinomycetes, but no BldD orthologues, except one in Saccharopolyspora erythraea, have been studied outside the streptomycetes. Here, it was revealed that the BldD orthologue AmBldD is essential for normal developmental processes in A. missouriensis. The AmBldD regulon seems to be different from the BldD regulon in Streptomyces coelicolor A3(2), but they share four genes that are involved in morphological differentiation in S. coelicolor A3(2).

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