scholarly journals Role of long-chain acyl-CoAs in the regulation of mycolic acid biosynthesis in mycobacteria

Open Biology ◽  
2017 ◽  
Vol 7 (7) ◽  
pp. 170087 ◽  
Author(s):  
Yi Ting Tsai ◽  
Valentina Salzman ◽  
Matías Cabruja ◽  
Gabriela Gago ◽  
Hugo Gramajo
Keyword(s):  
Cell Envelope ◽  
Phospholipid Composition ◽  
Mycolic Acid ◽  
Transcriptional Level ◽  
Direct Role ◽  
Conditional Mutant ◽  
In The Wild ◽  
Fas Ii

One of the dominant features of the biology of Mycobacterium tuberculosis , and other mycobacteria, is the mycobacterial cell envelope with its exceptional complex composition. Mycolic acids are major and very specific components of the cell envelope and play a key role in its architecture and impermeability. Biosynthesis of mycolic acid (MA) precursors requires two types of fatty acid synthases, FAS I and FAS II, which should work in concert in order to keep lipid homeostasis tightly regulated. Both FAS systems are regulated at their transcriptional level by specific regulatory proteins. FasR regulates components of the FAS I system, whereas MabR and FadR regulate components of the FAS II system. In this article, by constructing a tight mabR conditional mutant in Mycobacterium smegmatis mc 2 155, we demonstrated that sub-physiological levels of MabR lead to a downregulation of the fasII genes, inferring that this protein is a transcriptional activator of the FAS II system. In vivo labelling experiments and lipidomic studies carried out in the wild-type and the mabR conditional mutant demonstrated that under conditions of reduced levels of MabR, there is a clear inhibition of biosynthesis of MAs, with a concomitant change in their relative composition, and of other MA-containing molecules. These studies also demonstrated a change in the phospholipid composition of the membrane of the mutant strain, with a significant increase of phosphatidylinositol. Gel shift assays carried out with MabR and P fasII as a probe in the presence of different chain-length acyl-CoAs strongly suggest that molecules longer than C 18 can be sensed by MabR to modulate its affinity for the operator sequences that it recognizes, and in that way switch on or off the MabR-dependent promoter. Finally, we demonstrated the direct role of MabR in the upregulation of the fasII operon genes after isoniazid treatment.

scholarly journals Mutations affecting the tRNA-splicing endonuclease activity of Saccharomyces cerevisiae.

Genetics ◽  
1988 ◽  
Vol 118 (4) ◽  
pp. 609-617
Author(s):  
M Winey ◽  
M R Culbertson
Keyword(s):  
Growth Defect ◽  
Temperature Sensitive ◽  
Gene Products ◽  
Endonuclease Activity ◽  
Temperature Dependent ◽  
Direct Role ◽  
Trna Splicing

Abstract Two unlinked mutations that alter the enzyme activity of tRNA-splicing endonuclease have been identified in yeast. The sen1-1 mutation, which maps on chromosome 12, causes temperature-sensitive growth, reduced in vitro endonuclease activity, and in vivo accumulation of unspliced pre-tRNAs. The sen2-1 mutation does not confer a detectable growth defect, but causes a temperature-dependent reduction of in vitro endonuclease activity. Pre-tRNAs do not accumulate in sen2-1 strains. The in vitro enzyme activities of sen1-1 and sen2-1 complement in extracts from a heterozygous diploid, but fail to complement in mixed extracts from separate sen1-1 and sen2-1 haploid strains. These results suggest a direct role for SEN gene products in the enzymatic removal of introns from tRNA that is distinct from the role of other products known to affect tRNA splicing.

Abstract 277: Elevated C-Reactive Protein Contributes to Preeclampsia via Kinin Signaling Pathways

Hypertension ◽  
2013 ◽  
Vol 62 (suppl_1) ◽  
Author(s):  
Nicholas Parchim ◽  
Wei Wang ◽  
Takayuki Iriyama ◽  
Chen Liu ◽  
Athar H Siddiqui ◽  
...  
Keyword(s):  
Acute Phase Reactant ◽  
Receptor Activation ◽  
C Reactive Protein ◽  
Direct Role ◽  
Human Trophoblast ◽  
Reactive Protein ◽  
Induced Hypertension ◽  
Pregnant Mice

Preeclampsia (PE) is a serious pregnancy disease characterized by hypertension and proteinuria. Despite intensive research efforts, the underlying cause of PE remains a mystery. PE is, however, associated with abnormalities of the immune system. Here we report that the levels of C-reactive protein (CRP), an important acute phase reactant, were significantly elevated in the plasma of human with PE at the third trimester. Next, we found that CRP protein levels in the placentas of PE patients were also significantly increased compared to controls. In an effort to determine the exact role of elevated CRP in PE, we infused CRP into pregnant mice. We found that injection of CRP into pregnant mice induced hypertension (170 mmHg mean systolic vs. 125 mmHg mean systolic control; p<0.05) and proteinuria (25 mg/ug vs 12 mg/ug vehicle; p<0.05), indicating the direct role of CRP in PE. CRP is known to bind with phosphocholine on damaged cell membranes. Recent studies identified that neurokinin B (NKB), a placental enriched neuropeptide and known pathogenic molecule for PE, is phosphocholinated. This posttranslational modification increases its stability and enhances NKB-mediated receptor activation. These findings raise an intriguing hypothesis that CRP may bind with NKB coupled to NK3R activation and contribute to PE. To test this hypothesis, we conducted a pulldown assay, and we found that CRP bound with NKB. Next, using a cellular invasion assay, we revealed that CRP decreased invasion of human trophoblast cells (0.7 to 0.07 invasion index, p<0.05), while treatment with an NK3R selective antagonist, SB222200, ameliorated this shallow invasion. Finally, we provided in vivo evidence that inhibition of NK3R by SB222200 or knockdown of NK3R by specific siRNA in a potent nanoparticle delivery system significantly reduced CRP-induced hypertension and proteinuria in pregnant mice (170 mmHg mean systolic CRP-injected vs. 130 mmHg mean systolic siRNA NK3R; p<0.05 and proteinuria 25 mg/ug vs. 15 mg/ug; p<0.05). Overall, our findings demonstrate that elevated CRP contributes to PE and NKB/NK3R is a novel mechanism underlying CRP-mediated shallow invasion and disease development. These studies suggest novel pathogenic biomarkers and innovative therapeutic targets for PE.

scholarly journals Transcription factor MBF-I interacts with metal regulatory elements of higher eucaryotic metallothionein genes.

1989 ◽  
Vol 9 (12) ◽  
pp. 5315-5323 ◽  
Author(s):  
J Imbert ◽  
M Zafarullah ◽  
V C Culotta ◽  
L Gedamu ◽  
D Hamer
Keyword(s):  
Gene Transcription ◽  
Regulatory Elements ◽  
Gene Promoters ◽  
Direct Role ◽  
Transcription In Vitro ◽  
Mouse Cells ◽  
Affinity Reagent

Metallothionein (MT) gene promoters in higher eucaryotes contain multiple metal regulatory elements (MREs) that are responsible for the metal induction of MT gene transcription. We identified and purified to near homogeneity a 74-kilodalton mouse nuclear protein that specifically binds to certain MRE sequences. This protein, MBF-I, was purified employing as an affinity reagent a trout MRE that is shown to be functional in mouse cells but which lacks the G+C-rich and SP1-like sequences found in many mammalian MT gene promoters. Using point-mutated MREs, we showed that there is a strong correlation between DNA binding in vitro and MT gene regulation in vivo, suggesting a direct role of MBF-I in MT gene transcription. We also showed that MBF-I can induce MT gene transcription in vitro in a mouse extract and that this stimulation requires zinc.

scholarly journals Regulation of Rtt107 Recruitment to Stalled DNA Replication Forks by the Cullin Rtt101 and the Rtt109 Acetyltransferase

2008 ◽  
Vol 19 (1) ◽  
pp. 171-180 ◽  
Author(s):  
Tania M. Roberts ◽  
Iram Waris Zaidi ◽  
Jessica A. Vaisica ◽  
Matthias Peter ◽  
Grant W. Brown
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Replication Forks ◽  
Chromatin Binding ◽  
Direct Role ◽  
Repair Enzymes ◽  
Damage Response ◽  
Stalled Replication Forks

RTT107 (ESC4, YHR154W) encodes a BRCA1 C-terminal domain protein that is important for recovery from DNA damage during S phase. Rtt107 is a substrate of the checkpoint kinase Mec1, and it forms complexes with DNA repair enzymes, including the nuclease subunit Slx4, but the role of Rtt107 in the DNA damage response remains unclear. We find that Rtt107 interacts with chromatin when cells are treated with compounds that cause replication forks to arrest. This damage-dependent chromatin binding requires the acetyltransferase Rtt109, but it does not require acetylation of the known Rtt109 target, histone H3-K56. Chromatin binding of Rtt107 also requires the cullin Rtt101, which seems to play a direct role in Rtt107 recruitment, because the two proteins are found in complex with each other. Finally, we provide evidence that Rtt107 is bound at or near stalled replication forks in vivo. Together, these results indicate that Rtt109, Rtt101, and Rtt107, which genetic evidence suggests are functionally related, form a DNA damage response pathway that recruits Rtt107 complexes to damaged or stalled replication forks.

scholarly journals Src-like Adaptor Protein Promotes the CD103+ dendritic Cell Homeostasis in the Lung

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 1339-1339
Author(s):  
Namit Sharma ◽  
Pan Zhongda ◽  
Tracy Lauren Smith ◽  
Savar Kaul ◽  
Emilie Ernoult ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Immune Response ◽  
Immune Cell ◽  
Conflicts Of Interest ◽  
Adaptor Protein ◽  
Cell Receptor ◽  
Apoptotic Cells ◽  
Direct Role

Abstract Dendritic cells (DCs) along with mast cells function as sentinels for the innate immune system and perform as antigen presenting cells (APCs) to mount an adaptive immune response against invading pathogen. FLT3 receptor tyrosine kinase signaling has been shown to regulate the homeostatic mechanisms of subsets of DCs particularly, CD103+DCs compared to CD11b+DCs. CD103+DCs are regarded as APCs with superior capabilities to mount an effective immune response, thus understanding their homeostasis mechanism(s)/function is of paramount importance to devise effective therapeutics including DC vaccines. The Src-like adapter protein (SLAP) has been shown to dampen the signaling downstream of receptor tyrosine kinases including FLT3, cKit, and immune cell receptors including T cell receptor, B cell receptor, and Granulocyte-monocyte colony stimulating factor receptor via by recruiting c-Cbl, an ubiquitin ligase. Here, we report that SLAP deficient mice (KO) have reduced numbers of CD103+DC in lung while equal numbers in liver and kidney compared to control mice. To further confirm reduced CD103+DC in the lung, efferocytosis assays that are dependent upon CD+103 DC in lung epithelium to cleanse the apoptotic cells were performed. Flow cytometric quantification of CD103+DCs that uptake fluorescently labeled apoptotic cells administered via intranasal route and migrate to mediastinal lymph nodes confirmed reduced number of CD103+DCs in SLAP KO mice. Further analysis of DC progenitor populations showed reduced pre-DC progenitor in the lung in SLAP KO mice while bone marrow compartment showed equal progenitor populations including pre-DC and common dendritic progenitors suggesting the role of SLAP in localized FLT3 signaling in the lung. Consistently, DCs in lymphoid compartment including spleen, thymus, inguinal and popliteal lymph node did not show any defects. Upon further dissecting the cellular mechanism, SLAP KO DCs showed increased apoptosis while having similar proliferation potential in vivo at steady state.Bone marrow progenitors from SLAP KO mice failed to generate mature DCs in the presence of FLT3 ligand in vitrodue to enhanced apoptosis at early time points. Also, submaximal inhibition of FLT3 with an inhibitor, quizartinib partially rescues the apoptotic phenotype of SLAP KO bone marrow progenitors suggesting a cell-intrinsic role of SLAP in the survival of DCs. Biochemical analysis revealed that SLAP is directly recruited to the juxta-membrane residues of the FLT3 receptor in an inducible manner suggesting a direct role of SLAP in the regulation of FLT3 signaling. Phosphoflow analysis of DCs generated in the combined presence of GMCSF and FLT3 ligands showed that SLAP promotes the signaling to SHP2 while perturbs signaling to the mTOR pathway. Together these results suggest that SLAP is a critical regulator of CD103+DCs homeostasis in selective peripheral organs including the lung. Disclosures No relevant conflicts of interest to declare.

scholarly journals The Involvement of Mycobacterium Type III-A CRISPR-Cas System in Oxidative Stress

2021 ◽  
Vol 12 ◽  
Author(s):  
Fan Yang ◽  
Lingqing Xu ◽  
Lujie Liang ◽  
Wanfei Liang ◽  
Jiachen Li ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Envelope ◽  
Reduction Process ◽  
Intracellular Survival ◽  
Host Immunity ◽  
Type I ◽  
Type Iii

Type I and type II CRISPR-Cas systems are employed to evade host immunity by targeting interference of bacteria’s own genes. Although Mycobacterium tuberculosis (M. tuberculosis), the causative agent of tuberculosis, possesses integrated type III-A CRISPR-Cas system, its role in mycobacteria remains obscure. Here, we observed that seven cas genes (csm2∼5, cas10, cas6) were upregulated in Mycobacterium bovis BCG under oxidative stress treatment, indicating the role of type III-A CRISPR-Cas system in oxidative stress. To explore the functional role of type III-A CRISPR-Cas system, TCC (Type III-A CRISPR-Cas system, including cas6, cas10, and csm2-6) mutant was generated. Deletion of TCC results in increased sensitivity in response to hydrogen peroxide and reduced cell envelope integrity. Analysis of RNA-seq dataset revealed that TCC impacted on the oxidation-reduction process and the composition of cell wall which is essential for mycobacterial envelop integrity. Moreover, disrupting TCC led to poor intracellular survival in vivo and in vitro. Finally, we showed for the first time that TCC contributed to the regulation of regulatory T cell population, supporting a role of TCC in modulating host immunity. Our finding reveals the important role of TCC in cell envelop homeostasis. Our work also highlights type III-A CRISPR-Cas system as an important factor for intracellular survival and host immunoregulation in mycobacteria, thus may be a potential target for therapy.

scholarly journals Regulation of d-Aspartate Oxidase Gene Expression by Pyruvate Metabolism in the Yeast Cryptococcus humicola

2021 ◽  
Vol 9 (12) ◽  
pp. 2444
Author(s):  
Daiki Imanishi ◽  
Sota Zaitsu ◽  
Shouji Takahashi
Keyword(s):  
Gene Expression ◽  
Growth Retardation ◽  
Wild Type Strain ◽  
Transcriptional Level ◽  
Oxidative Deamination ◽  
Pyruvate Metabolism ◽  
Oxidase Gene ◽  
Cryptococcus Humicola ◽  
In The Wild

d-Aspartate oxidase (DDO) is a peroxisomal flavoenzyme that catalyzes the oxidative deamination of acidic d-amino acids. In the yeast Cryptococcus humicola strain UJ1, the enzyme ChDDO is essential for d-Asp utilization and is expressed only in the presence of d-Asp. Pyruvate carboxylase (Pyc) catalyzes the conversion of pyruvate to oxaloacetate and is involved in the import and activation of certain peroxisomal flavoenzymes in yeasts. In this study, we analyzed the role of Pyc in the expression of ChDDO gene in C. humicola strain UJ1. PYC gene disruption (∆Chpyc1) in strain UJ1 resulted in growth retardation on glucose and NH4Cl medium. The growth was restored by supplying oxaloacetate from l-Asp or α-ketoglutarate by a transaminase. On the other hand, the supply of oxaloacetate from d-Asp by ChDDO was not able to prevent growth retardation because of a significant decrease in ChDDO gene expression at the transcriptional level. The addition of pyruvate significantly decreased ChDDO gene transcription in the ∆Chpyc1 strain but increased the same in the wild-type strain, even though the intracellular pyruvate content was similar in both strains. These results suggest that ChDDO gene expression might be regulated by pyruvate metabolism, as well as by the presence of d-Asp.

scholarly journals Wnt/beta-catenin signalling is dispensable for adult neural stem cell homeostasis and activation

2020 ◽  
Author(s):  
Sophie H. L. Austin ◽  
Lachlan Harris ◽  
Oana Paun ◽  
Piero Rigo ◽  
François Guillemot ◽  
...  
Keyword(s):  
Stem Cell ◽  
Beta Catenin ◽  
Dependent Manner ◽  
Direct Role ◽  
Adult Nscs ◽  
Hippocampal Networks ◽  
Dose Dependent

AbstractAdult mouse hippocampal neural stem cells (NSCs) generate new neurons that integrate into existing hippocampal networks and modulate mood and memory. These NSCs are largely quiescent and are stimulated by niche signals to activate and produce neurons. Wnt/β-catenin signalling acts at different steps along the hippocampal neurogenic lineage and has been shown to promote the proliferation of intermediate progenitor cells. However, whether it has a direct role in the regulation of NSCs still remains unclear. Here we used Wnt/β-catenin reporters and transcriptomic data from in vivo and in vitro models to show that both active and quiescent adult NSCs respond to Wnt/β-catenin signalling. Wnt/β-catenin stimulation instructed neuronal differentiation of active NSCs and promoted the activation or differentiation of quiescent NSCs in a dose-dependent manner. However, we found that inhibiting NSCs response to Wnt, by conditionally deleting β-catenin, did not affect their activation or maintenance of their stem cell characteristics. Together, our results indicate that whilst NSCs do respond to Wnt/β-catenin stimulation in a dose-dependent and state-specific manner, Wnt/β-catenin signalling is not cell-autonomously required to maintain NSC homeostasis, which could reconcile some of the contradictions in the literature as to the role of Wnt/β-catenin signalling in adult hippocampal NSCs.

scholarly journals Exploring miR-9 Involvement in Ciona intestinalis Neural Development Using Peptide Nucleic Acids

2020 ◽  
Vol 21 (6) ◽  
pp. 2001
Author(s):  
Silvia Mercurio ◽  
Silvia Cauteruccio ◽  
Raoul Manenti ◽  
Simona Candiani ◽  
Giorgio Scarì ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Nucleic Acids ◽  
Neural Development ◽  
Peptide Nucleic Acids ◽  
Model Organism ◽  
Ciona Intestinalis ◽  
Transcriptional Level ◽  
Regulate Gene Expression

The microRNAs are small RNAs that regulate gene expression at the post-transcriptional level and can be involved in the onset of neurodegenerative diseases and cancer. They are emerging as possible targets for antisense-based therapy, even though the in vivo stability of miRNA analogues is still questioned. We tested the ability of peptide nucleic acids, a novel class of nucleic acid mimics, to downregulate miR-9 in vivo in an invertebrate model organism, the ascidian Ciona intestinalis, by microinjection of antisense molecules in the eggs. It is known that miR-9 is a well-conserved microRNA in bilaterians and we found that it is expressed in epidermal sensory neurons of the tail in the larva of C. intestinalis. Larvae developed from injected eggs showed a reduced differentiation of tail neurons, confirming the possibility to use peptide nucleic acid PNA to downregulate miRNA in a whole organism. By identifying putative targets of miR-9, we discuss the role of this miRNA in the development of the peripheral nervous system of ascidians.

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