Circularized chromosome with a large palindromic structure in Streptomyces griseus mutants.
Ontology highlight
ABSTRACT:
SUBMITTER: Uchida T
PROVIDER: S-EPMC415753 | biostudies-other | 2004 Jun
REPOSITORIES: biostudies-other
Similar Datasets
Project description:UV irradiation of Streptomyces griseus 2247 yielded a new chromosomal deletion mutant, MM9. Restriction and sequencing analysis revealed that homologous recombination between two similar lipoprotein-like open reading frames, which are located 450 and 250 kb from the left and right ends, respectively, caused chromosomal arm replacement. As a result, new 450-kb terminal inverted repeats (TIRs) were formed in place of the original 24-kb TIRs. Frequent homologous recombinations in Streptomyces strains suggest that telomere deletions can usually be repaired by recombinational DNA repair functioning between the intact and deleted TIR sequences on the same chromosome.
| S-EPMC142817 | biostudies-literature
Project description:In Streptomyces griseus, A-factor (2-isocapryloyl-3R-hydroxymethyl-gamma-butyrolactone) serves as a microbial hormone that switches on many genes required for streptomycin production and morphological development. An open reading frame (Orf1) showing high sequence similarity to oligoribonucleases of various origins is present just downstream of adpA, one of the A-factor-dependent genes. Orf1 was named OrnA (oligoribonuclease A) because it showed 3'-to-5' exo-oligoribonuclease activity, releasing [(32)P]CMP from ApCpC[(32)P]pC used as a substrate. Reverse transcription-PCR and S1 nuclease mapping analyses revealed that ornA was transcribed from two promoters; one was a developmentally regulated, A-factor-dependent promoter in front of adpA, and the other was a constitutive promoter in front of the ornA coding sequence. Transcription of ornA was thus additively enhanced at the initiation stage for secondary metabolism and aerial mycelium formation. ornA-disrupted strains grew slowly and scarcely formed aerial mycelium. ornA homologues were distributed in a wide variety of Streptomyces species, including S. coelicolor A3(2), as determined by Southern hybridization analysis. Disruption of the ornA homologue in S. coelicolor A3(2) also caused phenotypes similar to those of the S. griseus DeltaornA strains. The OrnA oligoribonucleases in Streptomyces species are therefore not essential but play an important role in vegetative growth and in the initiation of differentiation.
| S-EPMC94641 | biostudies-literature
Project description:We performed ribosome profiling which is the deep-sequencing of mRNA fragments protected by translating ribosome for two Streptomyces species through different growth phases to provide the translatome data
2020-03-03 | GSE138278 | GEO
Project description:When present in multiple copies, orf1590 restored sporulation to class IIIA bald mutants of Streptomyces griseus, which form sporulation septa and thick spore walls prematurely. The orf1590 alleles from class IIIA bald mutants restored sporulation upon introduction at a high copy number into those same mutants, and the nucleotide sequence of one of these alleles was identical to that of the wild-type strain. We conclude that overexpression of orf1590 suppresses the defect in class IIIA bald mutants. Previous nucleotide sequence and transcript analyses suggested that orf1590 could encode two related proteins, P56 and P49.5, from nested coding sequences. A mutation that prevented the synthesis of P56 without altering the coding sequence for P49.5 eliminated the function of orf1590, as did amino acid substitutions in the putative helix-turn-helix domain located at the N terminus of P56 and absent from P49.5. To determine the coding capacity of orf1590, we analyzed translational fusions between orf1590 and the neo gene from Tn5. Measurement of the expression of fusions to the wild-type and mutant alleles of orf1590 indicated that P56 was the sole product of orf1590 during vegetative growth. Attempts to generate a nonfunctional frameshift mutation in orf1590 were unsuccessful in the absence of a second-site bald mutation, suggesting that orf1590 may be required during vegetative growth by preventing early sporulation. Our results are consistent with the hypothesis that P56 at a high level delays the premature synthesis of sporulation septa and spore walls in class IIIA mutants.
| S-EPMC178022 | biostudies-other
Project description:Zincophorin is a polyketide antibiotic that possesses potent activity against Gram-positive bacteria, including human pathogens. While a number of total syntheses of this highly functionalized natural product were reported since its initial discovery, the genetic basis for the biosynthesis of zincophorin has remained unclear. In this study, the co-linearity inherent to polyketide pathways was used to identify the zincophorin biosynthesis gene cluster in the genome of the natural producer Streptomyces griseus HKI 0741. Interestingly, the same locus is fully conserved in the streptomycin-producing actinomycete S. griseus IFO 13350, suggesting that the latter bacterium is also capable of zincophorin biosynthesis. Biological profiling of zincophorin revealed a dose-dependent inhibition of the Gram-positive bacterium Streptococcus pneumoniae. The antibacterial effect, however, is accompanied by cytotoxicity. Antibiotic and cytotoxic activities were completely abolished upon esterification of the carboxylic acid group in zincophorin.
| S-EPMC6301713 | biostudies-literature
Project description:The amf gene cluster was previously identified as a regulator for the onset of aerial-mycelium formation in Streptomyces griseus. The nucleotide sequences of amf and its counterparts in other species revealed a conserved gene organization consisting of five open reading frames. A nonsense mutation in amfS, encoding a 43-amino-acid peptide, caused significant blocking of aerial-mycelium formation and streptomycin production, suggesting its role as a regulatory molecule. Extracellular-complementation tests for the aerial-mycelium-deficient phenotype of the amfS mutant demonstrated that AmfS was secreted by the wild-type strain. A null mutation in amfBA, encoding HlyB-like membrane translocators, abolished the extracellular AmfS activity without affecting the wild-type morphology, which suggests that AmfBA is involved not in production but in export of AmfS. A synthetic C-terminal octapeptide partially induced aerial-mycelium formation in the amfS mutant, which suggests that an AmfS derivative, but not AmfS itself, serves as an extracellular morphogen.
| S-EPMC134859 | biostudies-literature
Project description:Chromomycin A3 is an antitumor drug produced by Streptomyces griseus subsp. griseus. It consists of a tricyclic aglycone with two aliphatic side chains and two O-glycosidically linked saccharide chains, a disaccharide of 4-O-acetyl-D-oliose (sugar A) and 4-O-methyl-D-oliose (sugar B), and a trisaccharide of D-olivose (sugar C), D-olivose (sugar D), and 4-O-acetyl-L-chromose B (sugar E). The chromomycin gene cluster contains four glycosyltransferase genes (cmmGI, cmmGII, cmmGIII, and cmmGIV), which were independently inactivated through gene replacement, generating mutants C60GI, C10GII, C10GIII, and C10GIV. Mutants C10GIV and C10GIII produced the known compounds premithramycinone and premithramycin A1, respectively, indicating the involvement of CmmGIV and CmmGIII in the sequential transfer of sugars C and D and possibly also of sugar E of the trisaccharide chain, to the 12a position of the tetracyclic intermediate premithramycinone. Mutant C10GII produced two new tetracyclic compounds lacking the disaccharide chain at the 8 position, named prechromomycin A3 and prechromomycin A2. All three compounds accumulated by mutant C60GI were tricyclic and lacked sugar B of the disaccharide chain, and they were named prechromomycin A4, 4A-O-deacetyl-3A-O-acetyl-prechromomycin A4, and 3A-O-acetyl-prechromomycin A4. CmmGII and CmmGI are therefore responsible for the formation of the disaccharide chain by incorporating, in a sequential manner, two D-oliosyl residues to the 8 position of the biosynthetic intermediate prechromomycin A3. A biosynthetic pathway is proposed for the glycosylation events in chromomycin A3 biosynthesis.
| S-EPMC1352227 | biostudies-literature
Project description:The five pronase fractions, A(1), A(2), B, C (trypsin-like), and D (elastolytic), obtained by ion-exchange chromatography, were found to be antigenically distinct. Antibodies to pronase inhibited the enzymic activity of each of the enzyme fractions. Pronase trypsin and bovine trypsin, although resembling each other in enzymic activity and in amino acid sequence around their active sites, did not cross-react antigenically with, nor was their enzymic activity inhibited by, the respective homologous antibodies. Inactivation of pronase trypsin by complexing with soya-bean inhibitor AA, was not associated with a decrease in capacity to precipitate with its antibody. It is assumed that the antigenic sites are located far enough from the catalytic site of the enzyme to allow it to precipitate immunologically even when the catalytic site was blocked.
| S-EPMC1179358 | biostudies-other
Project description:Streptomycetes are soil microorganisms with the potential to produce a broad spectrum of secondary metabolities. The production of antibiotics is accompanied by a decrease in protein synthesis, which raises the question of how these bacteria survived the transition from the primary to the secondary metabolism. Translating ribosomes incapable to properly elongate or terminate polypeptide chain activate bacterial trans-translation system. Abundance and stability of the tmRNA during growth of Streptomyces collinus and Streptomyces griseus producing kirromycin and streptomycin, respectively, was analysed. The level of tmRNA is mostly proportional to the activity of the translational system. We demonstrate that the addition of sub-inhibitory concentrations of produced antibiotics to the cultures from the beginning of the exponential phase of growth leads to an increase in tmRNA levels and to an incorporation of amino acids into the tag-peptides at trans-translation of stalled ribosomes. These findings suggest that produced antibiotics induce tmRNA that facilitate reactivation of stalled complex of ribosomes and maintain viability. The effect of antibiotics that inhibit the cell-wall turnover, DNA, RNA or protein synthesis on the level of tmRNA was examined. Antibiotics interfering with ribosomal target sites are more effective at stimulation of the tmRNA level in streptomycetes examined than those affecting the synthesis of DNA, RNA or the cell wall.
| S-EPMC3815426 | biostudies-literature
Project description:Small noncoding RNAs (sRNAs) have been shown to control diverse cellular processes in prokaryotes. To identify and characterize novel bacterial sRNAs, a gram-positive, soil-inhabiting, filamentous bacterium, Streptomyces griseus, was examined, on the assumption that Streptomyces should express sRNAs as important regulators of morphological and physiological differentiation. By bioinformatics investigation, 54 sRNA candidates, which were encoded on intergenic regions of the S. griseus chromosome and were highly conserved in those of both Streptomyces coelicolor A3(2) and Streptomyces avermitilis, were selected. Of these 54 sRNA candidates, 17 transcripts were detected by Northern blot analysis of the total RNAs isolated from cells grown on solid medium. Then, the direction of transcription of each sRNA candidate gene was determined by S1 nuclease mapping, followed by exclusion of four sRNA candidates that were considered riboswitches of their downstream open reading frames (ORFs). Finally, a further sRNA candidate was excluded because it was cotranscribed with the upstream ORF determined by reverse transcription-PCR. Thus, 12 sRNAs ranging in size from 40 to 300 nucleotides were identified in S. griseus. Seven of them were apparently transcribed in a growth phase-dependent manner. Furthermore, of the 12 sRNAs, the expression profiles of 7 were significantly influenced by a mutation of adpA, which encodes the central transcriptional regulator of the A-factor regulatory cascade involved in both morphological differentiation and secondary metabolism in S. griseus. However, disruption of all 12 sRNA genes showed no detectable phenotypic changes; all the disruptants grew and formed aerial mycelium and spores with the same time course as the wild-type strain on various media and produced streptomycin similarly to the wild-type strain.
| S-EPMC2715712 | biostudies-literature