scholarly journals Lack of the Bacterial Phytochrome Protein Decreases Deinococcus radiodurans Resistance to Mitomycin C

2021 ◽  
Vol 12 ◽  
Author(s):  
Jong-Hyun Jung ◽  
Soyoung Jeong ◽  
Seonghun Im ◽  
Min-Kyu Kim ◽  
Ho Seong Seo ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cell Survival ◽  
Mitomycin C ◽  
Mutant Strain ◽  
Double Mutant ◽  
Deinococcus Radiodurans ◽  
Red Light ◽  
Double Mutant Strain ◽  
Significant Difference

Deinococcus radiodurans known for its extraordinary resistance to ionizing radiation contains bacterial phytochrome (BphP), a member of the family of red/far-red light-sensing proteins. In this study, we constructed a bphP mutant strain (ΔbphP) to investigate the role of D. radiodurans BphP (DrBphP) in the DNA damage response. When cells were incubated under light and dark conditions following exposure to DNA damaging agents, such as γ- and UV-radiation and mitomycin C (MMC), no significant difference in cell survival was observed between the wild-type D. radiodurans strain (WT) and ΔbphP. However, when continuously exposed to MMC under light conditions, the WT strain notably exhibited increased survival compared to cells grown in the dark. The increased survival was not observed in the ΔbphP strain. These results are indicative of the protective role of light-activated DrBphP in the presence of MMC. Site-directed mutagenesis revealed that the conserved amino acids Cys-24 and His-532 involved in chromophore binding and signal transduction, respectively, were essential for the protective function of DrBphP. Inactivation of the cognate response regulator (RR; DrBphR) of DrBphP increased MMC resistance in the dark. In trans complementation of the bphP bphR double mutant strain (ΔbphPR) with DrBphR decreased MMC resistance. Considering that DrBphP acts as a light-activated phosphatase that dephosphorylates DrBphR, it appears that phosphorylated DrBphR exerts a negative effect on cell survival in the presence of MMC. DrBphP overexpression resulted in an increase in MMC resistance of ΔbphPR, implying that other RRs might be involved in the DrBphP-mediated signaling pathway. A mutant lacking the dr_0781 gene (Δdr_0781) demonstrated the same MMC phenotype as ΔbphR. Survival was further increased in the bphR dr_0781 double mutant strain compared to each single mutant ΔbphR or Δdr_0781, suggesting that DR_0781 is also involved in the DrBphP-dependent MMC sensitivity. This study uncovered a previously unknown phenomenon of red/far-red light-dependent DNA damage survival mediated by BphP by identifying the conditions under which DrBphP exhibits a fitness advantage.

scholarly journals Epistatic and Synergistic Interactions Between Circadian Clock Mutations in Neurospora crassa

Genetics ◽  
2001 ◽  
Vol 159 (2) ◽  
pp. 537-543
Author(s):  
Louis W Morgan ◽  
Jerry F Feldman
Keyword(s):  
Circadian Clock ◽  
Neurospora Crassa ◽  
Mutant Strain ◽  
Temperature Compensation ◽  
Double Mutant ◽  
Synergistic Interactions ◽  
Long Period ◽  
Double Mutant Strain ◽  
Short Period ◽  
Compensation Mechanisms

Abstract We identified a series of epistatic and synergistic interactions among the circadian clock mutations of Neurospora crassa that indicate possible physical interactions among the various clock components encoded by these genes. The period-6 (prd-6) mutation, a short-period temperature-sensitive clock mutation, is epistatic to both the prd-2 and prd-3 mutations. The prd-2 and prd-3 long-period mutations show a synergistic interaction in that the period length of the double mutant strain is considerably longer than predicted. In addition, the prd-2 prd-3 double mutant strain also exhibits overcompensation to changes in ambient temperature, suggesting a role in the temperature compensation machinery of the clock. The prd-2, prd-3, and prd-6 mutations also show significant interactions with the frq7 long-period mutation. These results suggest that the gene products of prd-2, prd-3, and prd-6 play an important role in both the timing and temperature compensation mechanisms of the circadian clock and may interact with the FRQ protein.

P-117 Pre-selected for an award: Bioinformatic analysis of NRF2 in the study of association of NRF2 variant and male infertility related to smoking status

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
D Aydos ◽  
O S Aydos ◽  
Y Yukselten ◽  
A Sunguroglu ◽  
K Aydos
Keyword(s):  
Dna Damage ◽  
Male Infertility ◽  
Mirna Expression ◽  
Smoking Status ◽  
Differentially Expressed ◽  
Control Group ◽  
Functional Variants ◽  
Significant Difference ◽  
Differentially Expressed Mirnas

Abstract Study question Could Nrf2 polymorphism (-617C>A; rs6721961) and oxidative stress (OS)-induced changes of signature seminal plasma (SP) miRNAs related to Nrf2 provide possible biomarkers of male infertility? Summary answer -617C>A SNP is associated with infertility through sperm OS DNA damage and miR-582-5p and miR-20a-5p, differentially represented between spermatozoa of smokers-non-smokers, might regulate Nrf2/ARE axis. What is known already As an extrinsic factor causing OS, smoking decreases male infertility by causing sperm membrane damage and DNA fragmentation. Expression of proteins related to the antioxidant defense system and phase 2 detoxifying enzymes controlled mainly by Nrf2/ARE pathway components is vital in managing OS-induced DNA damage. miRNAs, which multiple of are produced abundantly in male germ cells throughout spermatogenesis, have been detected in SP and contribute to multiple biological processes related to male reproductive events. miRNA-expression alterations may be induced in response to OS and without involving DNA sequence changes, miRNAs can provide additional mechanism of regulating the Nrf2 gene expression. Study design, size, duration Wild-type (WT) and SNP (-617) alleles in the Nrf2 gene were studied in 100 infertile cases and 100 controls and their associations with seminal parameters in relation to smoking status were assessed. In infertile cases, sperm DNA damage level was determined and compared among Nrf2 genotypes. Interactions between differentially expressed miRNAs (DEMIs) in response to smoking and Nrf2/ARE pathway components were visualized on a miRNA-mRNA regulatory network using CluePedia (v1.5.7) plugin of Cytoscape software (v3.8.2). Participants/materials, setting, methods Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was utilized to genotype the Nrf2 SNP (-617). DNA damages were analyzed by Comet assay. DEMIs were identified by a comprehensive bioinformatics analysis using the miRNA expression dataset GSE44134 downloaded from the GEO database. Predicted targets of DEMIs in smokers were identified by mirDIP portal. Known interactions between Nrf2 and its first neighbors were visualized after selecting STRING-actions, miRTarBase and miRecords validated miRNA source files from CluePedia panel. Main results and the role of chance There was significant difference for Nrf2 polymorphism between fertile and infertile males. The A allele was detected more frequently in the patient group; (P = 0.001). The frequencies of the C and A alleles of the Nrf2 were 62% and 38% in patients, and 78% and 44% in control group. The AA genotype was higher in the infertiles; 14% vs. 3% (P = 0.001). In smokers, sperm quality decreased significantly in AA genotype. The risk of DNA damage was highest with 224.58 AU in the AA genotype group, whereas it is the lowest with 164.56 AU in those carrying the CC genotype (P < 0.005). 21 differentially expressed miRNAs (including 7 downregulated and 14 upregulated in smokers) were identified. Among the upregulated DEMIs, miR-582-5p, miR-20a-5p, miR-573, miR-186-5p, miR-499a-5p were found to target the Nrf2 mRNA, suggesting their usage as biomarkers capable of indicating the antioxidant ability of the male reproductive system. The interrelations between Nrf2/Nrf2 direct interactors and DEMIs revealed the regulatory role of hsa-miR-20a-5p in SQSTM1/p62-Keap1-Nrf2 axis linked to selective autophagy. hsa-miR-582-5p was found to regulate the JNK/Jun/caspase-3 pathway, previously shown to be activated in response to OS, in which JUN can activate or suppress the Nrf2 expression. Limitations, reasons for caution Small number of cases while evaluating the effect of smoking weakens our ability to generalize the results. Including other coexisting factors and larger patient groups carrying other functional variants of Nrf2 as well as confirming the results at the protein level would further strengthen the results of the study. Wider implications of the findings This study is the first to report -617C>A polymorphism in the Nrf2 gene in the Turkish population and such a SNP may cause impaired fertility in men, especially in smokers, through oxidative metabolism. Considering these data may be valuable in determining risk groups. Trial registration number N/A

Characterizing KAS Enzymes Using the E. Coli Double Mutant Strain CY244

2003 ◽  
pp. 65-68
Author(s):  
Anne Vinther Rasmussen ◽  
Rie Yasuno ◽  
Penny von Wettstein-Knowles
Keyword(s):  
Mutant Strain ◽  
Double Mutant ◽  
E Coli ◽  
Double Mutant Strain

scholarly journals PtrB of Pseudomonas aeruginosa Suppresses the Type III Secretion System under the Stress of DNA Damage

2005 ◽  
Vol 187 (17) ◽  
pp. 6058-6068 ◽  
Author(s):  
Weihui Wu ◽  
Shouguang Jin
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Dna Damage ◽  
Mitomycin C ◽  
Type Iii Secretion ◽  
Double Mutant ◽  
Type Iii Secretion System ◽  
Sos Response ◽  
Secretion System ◽  
Wild Type ◽  
Type Iii

ABSTRACT In a search for regulatory genes of the type III secretion system (TTSS) in Pseudomonas aeruginosa, transposon (Tn5) insertional mutants of the prtR gene were found defective in the TTSS. PrtR is an inhibitor of prtN, which encodes a transcriptional activator for pyocin synthesis genes. In P. aeruginosa, pyocin synthesis is activated when PrtR is degraded during the SOS response. Treatment of a wild-type P. aeruginosa strain with mitomycin C, a DNA-damaging agent, resulted in the inhibition of TTSS activation. A prtR/prtN double mutant had the same TTSS defect as the prtR mutant, and complementation by a prtR gene but not by a prtN gene restored the TTSS function. Also, overexpression of the prtN gene in wild-type PAK had no effect on the TTSS; thus, PrtN is not involved in the repression of the TTSS. To identify the PrtR-regulated TTSS repressor, another round of Tn mutagenesis was carried out in the background of a prtR/prtN double mutant. Insertion in a small gene, designated ptrB, restored the normal TTSS activity. Expression of ptrB is specifically repressed by PrtR, and mitomycin C-mediated suppression of the TTSS is also abolished in a ptrB mutant strain. Therefore, PtrB is a new TTSS repressor that coordinates TTSS repression and pyocin synthesis under the stress of DNA damage.

scholarly journals On the (un)coupling of the chromophore, tongue interactions, and overall conformation in a bacterial phytochrome

2018 ◽  
Vol 293 (21) ◽  
pp. 8161-8172 ◽  
Author(s):  
Heikki Takala ◽  
Heli K. Lehtivuori ◽  
Oskar Berntsson ◽  
Ashley Hughes ◽  
Rahul Nanekar ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Structural Changes ◽  
Deinococcus Radiodurans ◽  
Red Light ◽  
Light Responses ◽  
Structural Mechanism ◽  
Weakly Coupled ◽  
Activity State ◽  
Conserved Tyrosine

Phytochromes are photoreceptors in plants, fungi, and various microorganisms and cycle between metastable red light–absorbing (Pr) and far-red light–absorbing (Pfr) states. Their light responses are thought to follow a conserved structural mechanism that is triggered by isomerization of the chromophore. Downstream structural changes involve refolding of the so-called tongue extension of the phytochrome-specific GAF-related (PHY) domain of the photoreceptor. The tongue is connected to the chromophore by conserved DIP and PRXSF motifs and a conserved tyrosine, but the role of these residues in signal transduction is not clear. Here, we examine the tongue interactions and their interplay with the chromophore by substituting the conserved tyrosine (Tyr263) in the phytochrome from the extremophile bacterium Deinococcus radiodurans with phenylalanine. Using optical and FTIR spectroscopy, X-ray solution scattering, and crystallography of chromophore-binding domain (CBD) and CBD–PHY fragments, we show that the absence of the Tyr263 hydroxyl destabilizes the β-sheet conformation of the tongue. This allowed the phytochrome to adopt an α-helical tongue conformation regardless of the chromophore state, hence distorting the activity state of the protein. Our crystal structures further revealed that water interactions are missing in the Y263F mutant, correlating with a decrease of the photoconversion yield and underpinning the functional role of Tyr263 in phytochrome conformational changes. We propose a model in which isomerization of the chromophore, refolding of the tongue, and globular conformational changes are represented as weakly coupled equilibria. The results also suggest that the phytochromes have several redundant signaling routes.

scholarly journals Role of Hsl7 in Morphology and Pathogenicity and Its Interaction with Other Signaling Components in the Plant Pathogen Ustilago maydis

2011 ◽  
Vol 10 (7) ◽  
pp. 869-883 ◽  
Author(s):  
C. Ben Lovely ◽  
Kavita Burman Aulakh ◽  
Michael H. Perlin
Keyword(s):  
Ammonium Sulfate ◽  
Mutant Strain ◽  
Double Mutant ◽  
Ustilago Maydis ◽  
Cell Length ◽  
Phytopathogenic Fungus ◽  
Nitrogen Base ◽  
Content Type ◽  
Dimorphic Transition ◽  
Double Mutant Strain

ABSTRACTThe phytopathogenic fungusUstilago maydisundergoes a dimorphic transition in response to mating pheromone, host, and environmental cues. On a solid medium deficient in ammonium (SLAD [0.17% yeast nitrogen base without ammonium sulfate or amino acids, 2% dextrose, 50 μM ammonium sulfate]),U. maydisproduces a filamentous colony morphology, while in liquid SLAD, the cells do not form filaments. The p21-activated protein kinases (PAKs) play a substantial role in regulating the dimorphic transition in fungi. The PAK-like Ste20 homologue Smu1 is required for a normal response to pheromone, via upregulation of pheromone expression, and virulence, and its disruption affects both processes. Our experiments suggest that Smu1 also regulates cell length and the filamentous response on solid SLAD medium. Yeast two-hybrid analysis suggested an Hsl7 homologue as a potential interacting partner of Smu1, and a unique open reading frame for such an arginine methyltransferase was detected in theU. maydisgenome sequence. Hsl7 regulates cell length and the filamentous response to solid SLAD in a fashion opposite to that of Smu1, but neither overexpression nor disruption ofhsl7attenuates virulence. Simultaneous disruption ofhsl7and overexpression ofsmu1lead to a hyperfilamentous response on solid SLAD. Moreover, only this double mutant strain forms filaments in liquid SLAD. The double mutant strain was also significantly reduced in virulence. A similar filamentous response in both solid and liquid SLAD was observed in strains lacking another PAK-like protein kinase involved in cytokinesis and polar growth, Cla4. Our data suggest that Hsl7 may regulate cell cycle progression, while both Smu1 and Cla4 appear to be involved in the filamentous response inU. maydis.

P–117 Bioinformatic analysis of NRF2 in the study of association of NRF2 variant and male infertility related to smoking status

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
D Aydos ◽  
O S Aydos ◽  
Y Yukselten ◽  
A Sunguroglu ◽  
K Aydos
Keyword(s):  
Dna Damage ◽  
Male Infertility ◽  
Mirna Expression ◽  
Smoking Status ◽  
Differentially Expressed ◽  
Control Group ◽  
Functional Variants ◽  
Significant Difference ◽  
Differentially Expressed Mirnas

Abstract Study question Could Nrf2 polymorphism (–617C>A; rs6721961) and oxidative stress (OS)-induced changes of signature seminal plasma (SP) miRNAs related to Nrf2 provide possible biomarkers of male infertility? Summary answer –617C>A SNP is associated with infertility through sperm OS DNA damage and miR–582–5p and miR–20a–5p, differentially represented between spermatozoa of smokers-non-smokers, might regulate Nrf2/ARE axis. What is known already As an extrinsic factor causing OS, smoking decreases male infertility by causing sperm membrane damage and DNA fragmentation. Expression of proteins related to the antioxidant defense system and phase 2 detoxifying enzymes controlled mainly by Nrf2/ARE pathway components is vital in managing OS-induced DNA damage. miRNAs, which multiple of are produced abundantly in male germ cells throughout spermatogenesis, have been detected in SP and contribute to multiple biological processes related to male reproductive events. miRNA-expression alterations may be induced in response to OS and without involving DNA sequence changes, miRNAs can provide additional mechanism of regulating the Nrf2 gene expression. Study design, size, duration Wild-type (WT) and SNP (–617) alleles in the Nrf2 gene were studied in 100 infertile cases and 100 controls and their associations with seminal parameters in relation to smoking status were assessed. In infertile cases, sperm DNA damage level was determined and compared among Nrf2 genotypes. Interactions between differentially expressed miRNAs (DEMIs) in response to smoking and Nrf2/ARE pathway components were visualized on a miRNA-mRNA regulatory network using CluePedia (v1.5.7) plugin of Cytoscape software (v3.8.2). Participants/materials, setting, methods Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was utilized to genotype the Nrf2 SNP (–617). DNA damages were analyzed by Comet assay. DEMIs were identified by a comprehensive bioinformatics analysis using the miRNA expression dataset GSE44134 downloaded from the GEO database. Predicted targets of DEMIs in smokers were identified by mirDIP portal. Known interactions between Nrf2 and its first neighbors were visualized after selecting STRING-actions, miRTarBase and miRecords validated miRNA source files from CluePedia panel. Main results and the role of chance There was significant difference for Nrf2 polymorphism between fertile and infertile males. The A allele was detected more frequently in the patient group; (P = 0.001). The frequencies of the C and A alleles of the Nrf2 were 62% and 38% in patients, and 78% and 44% in control group. The AA genotype was higher in the infertiles; 14% vs. 3% (P = 0.001). In smokers, sperm quality decreased significantly in AA genotype. The risk of DNA damage was highest with 224.58 AU in the AA genotype group, whereas it is the lowest with 164.56 AU in those carrying the CC genotype (P < 0.005). 21 differentially expressed miRNAs (including 7 downregulated and 14 upregulated in smokers) were identified. Among the upregulated DEMIs, miR–582–5p, miR–20a–5p, miR–573, miR–186–5p, miR–499a–5p were found to target the Nrf2 mRNA, suggesting their usage as biomarkers capable of indicating the antioxidant ability of the male reproductive system. The interrelations between Nrf2/Nrf2 direct interactors and DEMIs revealed the regulatory role of hsa-miR–20a–5p in SQSTM1/p62-Keap1-Nrf2 axis linked to selective autophagy. hsa-miR–582–5p was found to regulate the JNK/Jun/caspase–3 pathway, previously shown to be activated in response to OS, in which JUN can activate or suppress the Nrf2 expression. Limitations, reasons for caution Small number of cases while evaluating the effect of smoking weakens our ability to generalize the results. Including other coexisting factors and larger patient groups carrying other functional variants of Nrf2 as well as confirming the results at the protein level would further strengthen the results of the study. Wider implications of the findings: This study is the first to report –617C>A polymorphism in the Nrf2 gene in the Turkish population and such a SNP may cause impaired fertility in men, especially in smokers, through oxidative metabolism. Considering these data may be valuable in determining risk groups. Trial registration number N/A

scholarly journals SIRT1 Promotes Cell Survival under Stress by Deacetylation-Dependent Deactivation of Poly(ADP-Ribose) Polymerase 1

2009 ◽  
Vol 29 (15) ◽  
pp. 4116-4129 ◽  
Author(s):  
Senthilkumar B. Rajamohan ◽  
Vinodkumar B. Pillai ◽  
Madhu Gupta ◽  
Nagalingam R. Sundaresan ◽  
Konstantin G. Birukov ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cell Death ◽  
Cell Survival ◽  
Cross Talk ◽  
Gene Promoter ◽  
Stress Conditions ◽  
Transcriptional Level ◽  
A Cell

ABSTRACT Poly(ADP-ribose) polymerase 1 (PARP1) and SIRT1 deacetylase are two NAD-dependent enzymes which play major roles in the decision of a cell to live or to die in a stress situation. Because of the dependence of both enzymes on NAD, cross talk between them has been suggested. Here, we show that PARP1 is acetylated after stress of cardiomyocytes, resulting in the activation of PARP1, which is independent of DNA damage. SIRT1 physically binds to and deacetylates PARP1. Increased acetylation of PARP1 was also detected in hearts of SIRT1−/− mice, compared to that detected in the hearts of SIRT1+/+ mice, confirming a role of SIRT1 in regulating the PARP1 acetylation in vivo. SIRT1-dependent deacetylation blocks PARP1 activity, and it protects cells from PARP1-mediated cell death. We also show that SIRT1 negatively regulates the activity of the PARP1 gene promoter, thus suggesting that the deacetylase controls the PARP1 activity at the transcriptional level as well. These data demonstrate that the activity of PARP1 is under the control of SIRT1, which is necessary for survival of cells under stress conditions.

scholarly journals Effect of a recD Mutation on DNA Damage Resistance and Transformation in Deinococcus radiodurans

2007 ◽  
Vol 189 (14) ◽  
pp. 5101-5107 ◽  
Author(s):  
Matthew D. Servinsky ◽  
Douglas A. Julin
Keyword(s):  
Hydrogen Peroxide ◽  
Dna Damage ◽  
Ionizing Radiation ◽  
Mitomycin C ◽  
Deinococcus Radiodurans ◽  
Uv Light ◽  
Gene Encoding ◽  
Significant Similarity ◽  
Damage Repair ◽  
Recbcd Enzyme

ABSTRACT The bacterium Deinococcus radiodurans is resistant to extremely high levels of DNA-damaging agents such as UV light, ionizing radiation, and chemicals such as hydrogen peroxide and mitomycin C. The organism is able to repair large numbers of double-strand breaks caused by ionizing radiation, in spite of the lack of the RecBCD enzyme, which is essential for double-strand DNA break repair in Escherichia coli and many other bacteria. The D. radiodurans genome sequence indicates that the organism lacks recB and recC genes, but there is a gene encoding a protein with significant similarity to the RecD protein of E. coli and other bacteria. We have generated D. radiodurans strains with a disruption or deletion of the recD gene. The recD mutants are more sensitive than wild-type cells to irradiation with gamma rays and UV light and to treatment with hydrogen peroxide, but they are not sensitive to treatment with mitomycin C and methyl methanesulfonate. The recD mutants also show greater efficiency of transformation by exogenous homologous DNA. These results are the first indication that the D. radiodurans RecD protein has a role in DNA damage repair and/or homologous recombination in the organism.

Concurrent modifications of the C-terminus and side ring of thiostrepton and their synergistic effects with respect to improving antibacterial activities

2016 ◽  
Vol 3 (4) ◽  
pp. 496-500 ◽  
Author(s):  
Shoufeng Wang ◽  
Qingfei Zheng ◽  
Jianfeng Wang ◽  
Dandan Chen ◽  
Yunsong Yu ◽  
...  
Keyword(s):  
Mutant Strain ◽  
Double Mutant ◽  
Synergistic Effects ◽  
Antibacterial Activities ◽  
Ring Structure ◽  
Quinaldic Acid ◽  
C Terminus ◽  
Double Mutant Strain

Five new C-terminally methylated TSR derivatives that varied in side-ring structure were obtained via the chemical feeding of quinaldic acid analogs to a double-mutant strain ΔtsrB/T.

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