scholarly journals Genetic Engineering of Streptomyces ghanaensis ATCC14672 for Improved Production of Moenomycins

2021 ◽  
Vol 10 (1) ◽  
pp. 30
Author(s):  
Roman Makitrynskyy ◽  
Olga Tsypik ◽  
Andreas Bechthold
Keyword(s):  
Genetic Engineering ◽  
Genome Engineering ◽  
Growth Parameters ◽  
Regulatory Gene ◽  
Morphological Differentiation ◽  
Production Spectrum ◽  
Bioactive Natural Products ◽  
Streptomyces Spp ◽  
Streptomyces Ghanaensis

Streptomycetes are soil-dwelling multicellular microorganisms famous for their unprecedented ability to synthesize numerous bioactive natural products (NPs). In addition to their rich arsenal of secondary metabolites, Streptomyces are characterized by complex morphological differentiation. Mostly, industrial production of NPs is done by submerged fermentation, where streptomycetes grow as a vegetative mycelium forming pellets. Often, suboptimal growth peculiarities are the major bottleneck for industrial exploitation. In this work, we employed genetic engineering approaches to improve the production of moenomycins (Mm) in Streptomyces ghanaensis, the only known natural direct inhibitors of bacterial peptidoglycan glycosyltransferses. We showed that in vivo elimination of binding sites for the pleiotropic regulator AdpA in the oriC region strongly influences growth and positively correlates with Mm accumulation. Additionally, a marker- and “scar”-less deletion of moeH5, encoding an amidotransferase from the Mm gene cluster, significantly narrows down the Mm production spectrum. Strikingly, antibiotic titers were strongly enhanced by the elimination of the pleiotropic regulatory gene wblA, involved in the late steps of morphogenesis. Altogether, we generated Mm overproducers with optimized growth parameters, which are useful for further genome engineering and chemoenzymatic generation of novel Mm derivatives. Analogously, such a scheme can be applied to other Streptomyces spp.

scholarly journals Repression of Antibiotic Production and Sporulation in Streptomyces coelicolor by Overexpression of a TetR Family Transcriptional Regulator

2010 ◽  
Vol 76 (23) ◽  
pp. 7741-7753 ◽  
Author(s):  
Delin Xu ◽  
Nicolas Seghezzi ◽  
Catherine Esnault ◽  
Marie-Joelle Virolle
Keyword(s):  
Target Genes ◽  
Antibiotic Production ◽  
Streptomyces Coelicolor ◽  
Regulatory Gene ◽  
Morphological Differentiation ◽  
Promoter Sequence ◽  
Inhibitory Effect ◽  
Binding Motif

ABSTRACT The overexpression of a regulatory gene of the TetR family (SCO3201) originating either from Streptomyces lividans or from Streptomyces coelicolor was shown to strongly repress antibiotic production (calcium-dependent antibiotic [CDA], undecylprodigiosin [RED], and actinorhodin [ACT]) of S. coelicolor and of the ppk mutant strain of S. lividans. Curiously, the overexpression of this gene also had a strong inhibitory effect on the sporulation process of S. coelicolor but not on that of S. lividans. SCO3201 was shown to negatively regulate its own transcription, and its DNA binding motif was found to overlap its −35 promoter sequence. The interruption of this gene in S. lividans or S. coelicolor did not lead to any obvious phenotypes, indicating that when overexpressed SCO3201 likely controls the expression of target genes of other TetR regulators involved in the regulation of the metabolic and morphological differentiation process in S. coelicolor. The direct and functional interaction of SCO3201 with the promoter region of scbA, a gene under the positive control of the TetR-like regulator, ScbR, was indeed demonstrated by in vitro as well as in vivo approaches.

Effects of growth phase and the developmentally significant bldA-specified tRNA on the membrane-associated proteome of Streptomyces coelicolor

Microbiology ◽  
2005 ◽  
Vol 151 (8) ◽  
pp. 2707-2720 ◽  
Author(s):  
Dae-Wi Kim ◽  
Keith F. Chater ◽  
Kye-Joon Lee ◽  
Andy Hesketh
Keyword(s):  
Minimal Medium ◽  
Streptomyces Coelicolor ◽  
Regulatory Gene ◽  
Transmembrane Helix ◽  
Morphological Differentiation ◽  
Hypothetical Proteins ◽  
Membrane Proteome ◽  
Protein Mass ◽  
Associated Proteins ◽  
Transporter Systems

Previous proteomic analyses of Streptomyces coelicolor by two-dimensional electrophoresis and protein mass fingerprinting focused on extracts from total cellular material. Here, the membrane-associated proteome of cultures grown in a liquid minimal medium was partially characterized. The products of some 120 genes were characterized from the membrane fraction, with 70 predicted to possess at least one transmembrane helix. A notably high proportion of ABC transporter systems was represented; the specific types detected provided a snapshot of the nutritional requirements of the mycelium. The membrane-associated proteins did not change very much in abundance in different phases of growth in liquid minimal medium. Identification of gene products not expected to be present in membrane protein extracts led to a reconsideration of the genome annotation in two cases, and supplemented scarce information on 11 hypothetical/conserved hypothetical proteins of unknown function. The wild-type membrane proteome was compared with that of a bldA mutant lacking the only tRNA capable of efficient translation of the rare UUA (leucine) codon. Such mutants are unaffected in vegetative growth but are defective in many aspects of secondary metabolism and morphological differentiation. There were a few clear changes in the membrane proteome of the mutant. In particular, two hypothetical proteins (SCO4244 and SCO4252) were completely absent from the bldA mutant, and this was associated with the TTA-containing regulatory gene SCO4263. Evidence for the control of a cluster of function-unknown genes by the SCO4263 regulator revealed a new aspect of the pleiotropic bldA phenotype.

scholarly journals CRISPR/Cas9-mediated genome engineering of CXCR4 decreases the malignancy of hepatocellular carcinoma cells in vitro and in vivo

2017 ◽  
Vol 37 (6) ◽  
pp. 3565-3571 ◽  
Author(s):  
Xiaoli Wang ◽  
Wenmei Zhang ◽  
Yan Ding ◽  
Xingrong Guo ◽  
Yahong Yuan ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Genome Engineering ◽  
Carcinoma Cells ◽  
Hepatocellular Carcinoma Cells

Matrigel induces thymosin beta 4 gene in differentiating endothelial cells

1995 ◽  
Vol 108 (12) ◽  
pp. 3685-3694 ◽  
Author(s):  
D.S. Grant ◽  
J.L. Kinsella ◽  
M.C. Kibbey ◽  
S. LaFlamme ◽  
P.D. Burbelo ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Basement Membrane ◽  
Morphological Differentiation ◽  
Tube Formation ◽  
Vessel Formation ◽  
Thymosin Beta 4 ◽  
Cdna Hybridization ◽  
Matrix Components ◽  
Cells Cultured

We performed differential cDNA hybridization using RNA from endothelial cells cultured for 4 hours on either plastic or basement membrane matrix (Matrigel), and identified early genes induced during the morphological differentiation into capillary-like tubes. The mRNA for one clone, thymosin beta 4, was increased 5-fold. Immunostaining localized thymosin beta 4 in vivo in both growing and mature vessels as well as in other tissues. Endothelial cells transfected with thymosin beta 4 showed an increased rate of attachment and spreading on matrix components, and an accelerated rate of tube formation on Matrigel. An antisense oligo to thymosin beta 4 inhibited tube formation on Matrigel. The results suggest that thymosin beta 4 is induced and likely involved in differentiating endothelial cells. Thymosin beta 4 may play a role in vessel formation in vivo.

scholarly journals Development of oriC-Based Plasmids for Mesoplasma florum

2017 ◽  
Vol 83 (7) ◽  
Author(s):  
Dominick Matteau ◽  
Marie-Eve Pepin ◽  
Vincent Baby ◽  
Samuel Gauthier ◽  
Mélissa Arango Giraldo ◽  
...  
Keyword(s):  
Systems Biology ◽  
Synthetic Biology ◽  
Genetic Engineering ◽  
Genome Engineering ◽  
Antibiotic Resistance Genes ◽  
Viable Cell ◽  
Pathogenic Potential ◽  
Strong Basis ◽  
Content Type ◽  
Basic Biology

ABSTRACT The near-minimal bacterium Mesoplasma florum constitutes an attractive model for systems biology and for the development of a simplified cell chassis in synthetic biology. However, the lack of genetic engineering tools for this microorganism has limited our capacity to understand its basic biology and modify its genome. To address this issue, we have evaluated the susceptibility of M. florum to common antibiotics and developed the first generation of artificial plasmids able to replicate in this bacterium. Selected regions of the predicted M. florum chromosomal origin of replication (oriC) were used to create different plasmid versions that were tested for their transformation frequency and stability. Using polyethylene glycol-mediated transformation, we observed that plasmids harboring both rpmH-dnaA and dnaA-dnaN intergenic regions, interspaced or not with a copy of the dnaA gene, resulted in a frequency of ∼4.1 × 10−6 transformants per viable cell and were stably maintained throughout multiple generations. In contrast, plasmids containing only one M. florum oriC intergenic region or the heterologous oriC region of Mycoplasma capricolum, Mycoplasma mycoides, or Spiroplasma citri failed to produce any detectable transformants. We also developed alternative transformation procedures based on electroporation and conjugation from Escherichia coli, reaching frequencies up to 7.87 × 10−6 and 8.44 × 10−7 transformants per viable cell, respectively. Finally, we demonstrated the functionality of antibiotic resistance genes active against tetracycline, puromycin, and spectinomycin/streptomycin in M. florum. Taken together, these valuable genetic tools will facilitate efforts toward building an M. florum-based near-minimal cellular chassis for synthetic biology. IMPORTANCE Mesoplasma florum constitutes an attractive model for systems biology and for the development of a simplified cell chassis in synthetic biology. M. florum is closely related to the mycoides cluster of mycoplasmas, which has become a model for whole-genome cloning, genome transplantation, and genome minimization. However, M. florum shows higher growth rates than other Mollicutes, has no known pathogenic potential, and possesses a significantly smaller genome that positions this species among some of the simplest free-living organisms. So far, the lack of genetic engineering tools has limited our capacity to understand the basic biology of M. florum in order to modify its genome. To address this issue, we have evaluated the susceptibility of M. florum to common antibiotics and developed the first artificial plasmids and transformation methods for this bacterium. This represents a strong basis for ongoing genome engineering efforts using this near-minimal microorganism.

scholarly journals Characterization, modelling and mitigation of gene expression burden in mammalian cells

2019 ◽  
Author(s):  
T Frei ◽  
F Cella ◽  
F Tedeschi ◽  
J Gutierrez ◽  
GB Stan ◽  
...  
Keyword(s):  
Gene Expression ◽  
Mammalian Cells ◽  
Genome Engineering ◽  
Host Cells ◽  
Genetic Circuits ◽  
Circuit Performance ◽  
Resource Requirements ◽  
Synthetic Circuit ◽  
Resource Aware

AbstractDespite recent advances in genome engineering, the design of genetic circuits in mammalian cells is still painstakingly slow and fraught with inexplicable failures. Here we demonstrate that competition for limited transcriptional and translational resources dynamically couples otherwise independent co-expressed exogenous genes, leading to diminished performance and contributing to the divergence between intended and actual function. We also show that the expression of endogenous genes is likewise impacted when genetic payloads are expressed in the host cells. Guided by a resource-aware mathematical model and our experimental finding that post-transcriptional regulators have a large capacity for resource redistribution, we identify and engineer natural and synthetic miRNA-based incoherent feedforward loop (iFFL) circuits that mitigate gene expression burden. The implementation of these circuits features the novel use of endogenous miRNAs as integral components of the engineered iFFL device, a versatile hybrid design that allows burden mitigation to be achieved across different cell-lines with minimal resource requirements. This study establishes the foundations for context-aware prediction and improvement of in vivo synthetic circuit performance, paving the way towards more rational synthetic construct design in mammalian cells.

scholarly journals Genetic engineering for in vivo optical interrogation of neuronal responses to cell type-specific silencing

2021 ◽  
Author(s):  
Firat Terzi ◽  
Johannes Knabbe ◽  
Sidney B. Cambridge
Keyword(s):  
High Resolution ◽  
Genetic Engineering ◽  
Transgene Expression ◽  
Neuronal Morphology ◽  
Dependent Manner ◽  
Cell Type ◽  
Fluorescent Marker ◽  
Genetic Perturbations ◽  
Cell Type Specific

SummaryGenetic engineering of quintuple transgenic brain tissue was used to establish a low background, Cre-dependent version of the inducible Tet-On system for fast, cell type-specific transgene expression in vivo. Co-expression of a constitutive, Cre-dependent fluorescent marker selectively allowed single cell analyses before and after inducible, tet-dependent transgene expression. Here, we used this method for acute, high-resolution manipulation of neuronal activity in the living brain. Single induction of the potassium channel Kir2.1 produced cell type-specific silencing within hours that lasted for at least three days. Longitudinal in vivo imaging of spontaneous calcium transients and neuronal morphology demonstrated that prolonged silencing did not alter spine densities or synaptic input strength. Furthermore, selective induction of Kir2.1 in parvalbumin interneurons increased the activity of surrounding neurons in a distance-dependent manner. This high-resolution, inducible interference and interval imaging of individual cells (high I5, ‘HighFive’) method thus allows visualizing temporally precise, genetic perturbations of defined cells.

scholarly journals Aβ42 oligomers trigger synaptic loss through CAMKK2-AMPK-dependent effectors coordinating mitochondrial fission and mitophagy

2019 ◽  
Author(s):  
Annie Lee ◽  
Chandana Kondapalli ◽  
Daniel M. Virga ◽  
Tommy L. Lewis ◽  
So Yeon Koo ◽  
...  
Keyword(s):  
Genome Engineering ◽  
Pyramidal Neurons ◽  
Es Cells ◽  
Mitochondrial Fission ◽  
Significant Loss ◽  
Synaptic Loss ◽  
Structural Remodeling ◽  
Swedish Mutation ◽  
Human Neurons

AbstractDuring the early stages of Alzheimer’s disease (AD) in both mouse models and human patients, soluble forms of Amyloid-β1-42 oligomers (Aβ42o) trigger loss of excitatory synapses (synaptotoxicity) in cortical and hippocampal pyramidal neurons (PNs) prior to the formation of insoluble Aβ plaques. We observed a spatially restricted structural remodeling of mitochondria in the apical tufts of CA1 PNs dendrites in the hAPPSWE,IND transgenic AD mouse model (J20), corresponding to the dendritic domain receiving presynaptic inputs from the entorhinal cortex and where the earliest synaptic loss is detected in vivo. We also observed significant loss of mitochondrial biomass in human neurons derived from a new model of human ES cells where CRISPR-Cas9-mediated genome engineering was used to introduce the ‘Swedish’ mutation bi-allelically (APPSWE/SWE). Recent work uncovered that Aβ42o mediates synaptic loss by over-activating the CAMKK2-AMPK kinase dyad, and that AMPK is a central regulator of mitochondria homeostasis in non-neuronal cells. Here, we demonstrate that Aβ42o-dependent over-activation of CAMKK2-AMPK mediates synaptic loss through coordinated MFF-dependent mitochondrial fission and ULK2-dependent mitophagy in dendrites of PNs. We also found that the ability of Aβ42o-dependent mitochondrial remodeling to trigger synaptic loss requires the ability of AMPK to phosphorylate Tau on Serine 262. Our results uncover a unifying stress-response pathway triggered by Aβo and causally linking structural remodeling of dendritic mitochondria to synaptic loss.

scholarly journals Organelle relationships in cultured 3T3-L1 preadipocytes.

1980 ◽  
Vol 87 (1) ◽  
pp. 180-196 ◽  
Author(s):  
A B Novikoff ◽  
P M Novikoff ◽  
O M Rosen ◽  
C S Rubin
Keyword(s):  
Spatial Relationship ◽  
Morphological Differentiation ◽  
Coated Vesicles ◽  
Coated Pits ◽  
Exogenous Lipid ◽  
Acetate Esterase ◽  
Alpha Naphthyl Acetate Esterase ◽  
High Level ◽  
Relationship Of

In differentiating 3T3-L1 cells, lipid spheres, the endoplasmic reticulum (ER), microperoxisomes, and mitochondria form "constellations" that may reflect the interplay of lipid metabolizing enzymes in these organelles. ER cisternae are also situated very close to "rosettes,"plasmalemmal specializations found in mature adipocytes in vivo. As in hepatocytes and absorptive cells of the intestine, this spatial relationship of ER and plasmalemma suggests a role for rosettes in the uptake of exogenous lipid precursors. The morphological differentiation of 3T3-L1 preadipocytes includes the loss of "stress fibers" and the appearance of microfilament like structures that encase, in a complex manner, the cytosolic lipid spheres that appear during differentiation. Other features described for the first time in 3T3-L1 preadipocytes include: (a) the presence of an extensive acid phosphatase (AcPase) positive GERL from which coated vesicles apparently arise (these coated vesicles display AcPase activity and are much smaller and far more numerous than the coated vesicles that seem to arise from the plasmalemmal coated pits); (b) the abundance of AcPase-positive autophagic vacuoles; and (c) a high level of alpha-naphthyl-acetate-esterase activity which, by light microscopy cytochemistry, appears to be localized in the cytosol.

scholarly journals Naturally Occurring Lactococcal Plasmid pAH90 Links Bacteriophage Resistance and Mobility Functions to a Food-Grade Selectable Marker

2001 ◽  
Vol 67 (2) ◽  
pp. 929-937 ◽  
Author(s):  
David O' Sullivan ◽  
R. Paul Ross ◽  
Denis P. Twomey ◽  
Gerald F. Fitzgerald ◽  
Colin Hill ◽  
...  
Keyword(s):  
Selectable Marker ◽  
Regulatory Gene ◽  
Strain Improvement ◽  
Lytic Cycle ◽  
Type I ◽  
Cadmium Resistance ◽  
Food Grade ◽  
Bacteriophage Resistance ◽  
Restriction Modification

ABSTRACT The bacteriophage resistance plasmid pAH90 (26,490 bp) is a natural cointegrate plasmid formed via homologous recombination between the type I restriction-modification specificity determinants (hsdS) of two smaller lactococcal plasmids, pAH33 (6,159 bp) and pAH82 (20,331 bp), giving rise to a bacteriophage-insensitive mutant following phage challenge (D. O'Sullivan, D. P. Twomey, A. Coffey, C. Hill, G. F. Fitzgerald, and R. P. Ross, Mol. Microbiol. 36:866–876; 2000). In this communication we provide evidence that the recombination event is favored by phage infection. The entire nucleotide sequence of plasmid pAH90 was determined and found to contain 24 open reading frames (ORFs) responsible for phenotypes which include restriction-modification, phage adsorption inhibition, plasmid replication, cadmium resistance, cobalt transport, and conjugative mobilization. The cadmium resistance property, encoded by the cadA gene, which has an associated regulatory gene (cadC), is of particular interest, as it facilitated the selection of pAH90 in other phage-sensitive lactococci after electroporation. In addition, we report the identification of a group II self-splicing intron bounded by two exons which have the capacity to encode a relaxase implicated in conjugation in gram-positive bacteria. The functionality of this intron was evident by demonstrating splicing in vivo. Given that pAH90 encodes potent phage defense systems which act at different stages in the phage lytic cycle, the linkage of these with a food-grade selectable marker on a replicon that can be mobilized among lactococci has significant potential for natural strain improvement for industrial dairy fermentations which are susceptible to phage inhibition.

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