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Copper interactions with DNA of chromatin and its role in neurodegenerative disorders

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Journal of Pharmaceutical Analysis 2013年第5期3卷 354-359页

作者： M.Govindaraju H.S.Shekar S.B.Sateesha P.Vasudeva Raju K.R.Sambasiva Rao K.S.J.Rao A.J.Rajamma Molecular Biophysics Unit Indian Institute of Science Department of Pharmacy Practice KIMS Hospital and Research CenterVIPS Department of Pharmaceutics Acharya & B.M.Reddy College of Pharmacy Department of Neuroscience Medical University of South Carolina Department of Biotechnology Acharya Nagarjuna University Centre for Neuroscience Institute for Scientifc Research and Technological services INDICASAT-AIP Department of Pharmacognosy KLEU's College of Pharmacy

In this study, we have demonstrated the conformational changes to DNA induced by abnormal interactions of copper using circular dichroism, in combination with UV-absorbance and fluorescence spectroscopy. Results confirm that binding of copper to bases of DNA in chromatin is concentration dependent. Binding efficiency of Cu2~ ions to DNA is increased in proportion to the degree of unwinding of the double helix induced by denaturation. Altered B-DNA conformation will alter the integrity of DNA which may affect the normal process of DNA replication and transcription. Copper induced DNA damage in the brain may cause neurotoxicity and the neuronal cell death and is implicated in Alzheimer＇s disease and other neurological disorders.

关键词： Human brain chromatin DNA Copper Neurodegenerative disorders

Effect of graded doses of acetylsalicylic acid on sperm chromatin integrity and maturity of germinal epithelium in adult male mouse

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Asian pacific Journal of Reproduction 2018年第5期7卷 214-219页

作者： Farzaneh Mahmoudi-Lafout Fahimeh Mohammadghasemi Department of Anatomy School of MedicineGuilan University of Medical SciencesRasht-Iran Cellular&Molecular Research Center School of MedicineGuilan University of Medical SciencesRasht-Iran

Objective:To evaluate the effect of graded doses of acetylsalicylic acid (ASA) on sperm chromatin integrity and sex hormones in the adult male ***:Forty-nine male adult mice were divided into seven groups. Control group received no drug, sham group received ASA solvent (dimethylsulfoxide 0.1%), groups 3 to 7 received different doses of 0.05, 0.10, 0.50, 1.00 and 5.00 mg ASA, daily for 14 d, respectively. On day 15, evaluations were made by sperm chromatin dispersion test for the study of DNA sperm integrity, radioimmunoassay for the study of testosterone and luteinizing hormone (LH) level and histopathology of testis for Jhonson's ***: ASA in groups 0.50, 1.00 and 5.00 mg reduced big halo sperms. DNA fragmentation significantly increased just in 5 mg group. Serum level of testosterone in doses of 0.50, 1.00 and 5.00 mg groups reduced significantly (P<0.01) while LH level was not affected. Johnson's score reduced in all ASA treated ***: Administration of ASA over the 14 days in dose of 5.00 mg increases sperm DNA fragmentation index and therefore reduces DNA integrity and in doses of 0.50, 1.00, 5.00 mg reduces serum testosterone level with no effect on LH. Generally, ASA has deleterious effects on the male reproductive indices even in low doses.

关键词： Acetylsalicylic acid chromatin DNA fragmentation Sex hormones

CRISPRi screen highlights chromatin regulation to be involved in formic acid tolerance in Saccharomyces cerevisiae

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Engineering Microbiology 2023年第2期3卷 57-64页

作者： Vaskar Mukherjee Ibai Lenitz Ulrika Lind Anders Blomberg Yvonne Nygård Department of Life Sciences Chalmers University of TechnologyGothenburgSweden Department of Chemistry and Molecular Biology University of GothenburgGothenburgSweden Department of Biorefinery and Energy RISE Research Institutes of SwedenÖrnsköldsvikSweden

Formic acid is one of the main weak acids in lignocellulosic hydrolysates that is known to be inhibitory to yeast growth even at low *** this study,we employed a CRISPR interference(CRISPRi)strain library comprising>9000 strains encompassing>98%of all essential and respiratory growth-essential genes,to study formic acid tolerance in Saccharomyces *** provide quantitative growth estimates on formic acid toler-ance,the strains were screened individually on solid medium supplemented with 140 mM formic acid using the Scan-o-Matic *** resistant and sensitive strains were characterized in liquid medium supplemented with formic acid and in synthetic hydrolysate medium containing a combination of *** with gR-NAs targeting genes associated with chromatin remodeling were significantly enriched for strains showing formic acid *** line with earlier findings on acetic acid tolerance,we found genes encoding proteins involved in intracellular vesicle transport enriched among formic acid sensitive *** growth of the strains in syn-thetic hydrolysate medium followed the same trend as when screened in medium supplemented with formic *** sensitive to formic acid had decreased growth in the synthetic hydrolysate and all strains that had im-proved growth in the presence of formic acid also grew better in the hydrolysate *** analysis of CRISPRi strains allowed identification of genes involved in tolerance mechanisms and provided novel engineering targets for bioengineering strains with increased resistance to inhibitors in lignocellulosic hydrolysates.

关键词： Formic acid Lignocellulosic hydrolysates CRISPRi library Screening Tolerance Yeast chromatin

Effect of low level, short wavelength ultraviolet radiation on sperm chromatin

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Asian pacific Journal of Reproduction 2017年第6期6卷 252-256页

作者： Rishika Sharma Nidhi Rajput Kanthi Bansal Hyacinth Highland Department of Zoology BMTC and Human GeneticsSchool of SciencesGujarat UniversityAhmedabad Safal Fertility Foundation and Bansal Hospital NavrangpuraAhmedabad

Objective:To evaluate the effects of low level ultraviolet (UV) radiation on sperm chromatin ***:The target study was divided into three groups: (i) males with proven fertility (n=40 ) was taken as GroupⅠ (control);(ii) Oligoasthenozoospermic (OAT) cases as GroupⅡ (n=36);(iii) males with unexplained infertility (MUI) cases (n=42) as GroupⅢ. Specific techniques were used to study the impact of UV radiation (Pre and Post UV exposure) on the sperm nuclear DNA viz. Aniline blue staining was for detection of immature chromatin. Chromomycin A3 fluorescence staining was used to determine protamine-DNA dissociation by intense fluorescence of protamine deficient sperm cells and neutral comet assay was for evaluation of DNA fragmentation. Statistical analysis was carried out using Student'st-test (GraphPad Prism Version-6). Level of significance was considered atPchromatin is at higher risk of DNA fragmentation in the infertile (OAT and MUI) cases due to UV irradiation (254 nm). Hence, short duration UV exposure is detrimental to sperm DNA which could affect ensuing generations.

关键词： Environmental stressors Ultraviolet radiation Sperm chromatin CMA3 staining Infertilit

The effects of DNA intercalators on chromatin of chicken red blood cells---differential extraction on nonhistone proteins

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Cell Research 1990年第1期1卷 105-118页

作者： Wang Fan and Zhu JingdeShanghai Institute of Cell Biology,Shanghai Open Labortory of Life Science, Academia Sinica, 320 Yue-yang Road, Shanghai 200031, China Shanghai Institute of Cell Biology Shanghai Open Labortory of Life Science Academia Sinica 320 Yue-Yang Road Shanghai 200031 China

Taking advantage of the effects on DNA secondary structure of two DNA-intercalators, ethidium bromide and chloroquine, we used each of them to treat nuclei from both mature erythrocytes and reticulocytes of chicken, as an alternative approach to study the relationships between DNA secondary structure, nuclear proteins and chromatin structure. We presented results of differential extraction of nuclear proteins from nuclei with DNA-intercalators, as well as preliminary characterization of these proteins. A 45kd protein is the major component in fractions extracted by both intercalators from nuclei from either mature erythrocytes or reticulocytes and seems to be a DNA-binding protein. Furthermore, from current concepts of functional aspects of DNA conformation and structural heterogeneity in chromatin and nuclear proteins, we have discussed both the significance of our resuits as well as technical aspects of this approach.

关键词： DNA intercalators ethidium bromide chloro-quine diphosphate chromatin nuclear proteins heparin affinity chromatography.

chromatin boundary elements organize genomic architecture and developmental gene regulation in Drosophila Hox clusters

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World Journal of Biological Chemistry 2016年第3期7卷 223-230页

作者： Zhibo Ma Mo Li Sharmila Roy Kevin J Liu Matthew L Romine Derrick C Lane Sapna K Patel Haini N Cai Department of Cellular Biology University of Georgia

The three-dimensional(3D) organization of the eukaryotic genome is critical for its proper function. Evidence suggests that extensive chromatin loops form the building blocks of the genomic architecture, separating genes and gene clusters into distinct functional domains. These loops are anchored in part by a special type of DNA elements called chromatin boundary elements(CBEs). CBEs were originally found to insulate neighboring genes by blocking influences of transcriptional enhancers or the spread of silent chromatin. However, recent results show that chromatin loops can also play a positive role in gene regulation by looping out intervening DNA and "delivering" remote enhancers to gene promoters. In addition, studies from human and model organisms indicate that the configuration of chromatin loops, many of which are tethered by CBEs, is dynamically regulated during cell differentiation. In particular, a recent work by Li et al has shown that the SF1 boundary, located in the Drosophila Hox cluster, regulates local genes by tethering different subsets of chromatin loops: One subset enclose a neighboring gene ftz, limiting its access by the surrounding Scr enhancers and restrict the spread of repressive histones during early embryogenesis; and the other loops subdivide the Scr regulatory region into independent domains of enhancer accessibility. The enhancer-blocking activity of these CBE elements varies greatly in strength and tissue distribution. Further, tandem pairing of SF1 and SF2 facilitate the bypass of distal enhancers in transgenic flies, providing a mechanism for endogenous enhancers to circumvent genomic interruptions resulting from chromosomal rearrangement. This study demonstrates how a network of chromatin boundaries, centrally organized by SF1, can remodel the 3D genome to facilitate gene regulation during development.

关键词： chromatin boundary element Insulator CTCF chromatin loop domains Drosophila Hox genes

Time for a Nuclear Meeting： Protein Trafficking and chromatin Dynamics Intersect in the Plant Circadian System

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Molecular Plant 2012年第3期5卷 554-565页

作者： Eva Herrero Seth J. Davis Max Planck Institute for Plant Breeding Research Carl-von-Linne＇weg 10 50829 Cologne Germany Present address： MRC National Institute for Medical Research The Ridgeway Mill Hill NW7 1AA London UK

Circadian clocks mediate adaptation to the 24-h world. In Arabidopsis, most circadian-clock components act in the nucleus as transcriptional regulators and generate rhythmic oscillations of transcript accumulation. In this review, we focus on post-transcriptional events that modulate the activity of circadian-clock components, such as phosphorylation, ubiquitination and proteasome-mediated degradation, changes in cellular localization, and protein-protein interactions. These processes have been found to be essential for circadian function, not only in plants, but also in other circadian systems. Moreover, light and clock signaling networks are highly interconnected. In the nucleus, light and clock compo- nents work together to generate transcriptional rhythms, leading to a general control of the timing of plant physiological processes.

关键词： circadian light signaling chromatin cellular dynamics ubiquitin/proteasome-mediated proteolysis

The Role of chromatin Modifications in Progression through Mouse Meiotic Prophase

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Journal of Genetics and Genomics 2014年第3期41卷 97-106页

作者： James H.Crichton Christopher J.Playfoot Ian R.Adams MRC Human Genetics Unit MRC Institute of Genetics and Molecular MedicineUniversity of EdinburghWestern General Hospital

Meiosis is a key event in gametogenesis that generates new combinations of genetic information and is required to reduce the chro- mosome content of the gametes. Meiotic chromosomes undergo a number of specialised events during prophase to allow meiotic recombination, homologous chromosome synapsis and reductional chromosome segregation to occur. In mammalian cells, DNA phys- ically associates with histones to form chromatin, which can be modified by methylation, phosphorylation, ubiquitination and acetylation to help regulate higher order chromatin structure, gene expression, and chromosome organisation. Recent studies have identified some of the enzymes responsible for generating chromatin modifications in meiotic mammalian cells, and shown that these chromatin modifying enzymes are required for key meiosis-specific events that occur during meiotic prophase. This review will discuss the role of chromatin modifications in meiotic recombination, homologous chromosome synapsis and regulation of meiotic gene expression in mammals.

关键词： Mouse Meiosis chromatin Chromosome Histone modification DNA methylation

Relationship between chromatin organization, mRNAs profile and human male gamete quality

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Asian Journal of Andrology 2007年第5期9卷 587-592页

作者： Isabelle Galeraud-Denis Sophie Lambard Serge Carreau UPRES EA 2608-USC INRA Université de Caen 14032-CAEN France Biology of Reproduction CHU-Caen Avenue G. Clemeanceau 14033-CAEN France Hospital St Antoine 184 Rue Fg St Antoine 75571-PARIS France

Spermiogenesis is a complex process leading to the formation of motile spermatozoa characterized by a highly stable chromatin compaction that transfers the paternal genome into the oocyte. It is commonly held that these haploid cells are devoid of transcriptional and translational activities and that the transcripts represent remnants of stored mRNAs. Recently, the chromatin organization of mature spermatozoa has been revisited as a double nucleoprotamine-nucleohistone structure possessing less-condensed regions sensitive to nuclease activity, which could be implicated in the expression of genes involved in the early embryo development. The existence of a complex population of mRNAs in human sperm is well-documented, but their role is not yet elucidated. Evidence for a latent transcriptional capacity and/or a potential de novo translation in mature spermatozoa from fertile men are essential for understanding the last steps of sperm maturation, such as capacitation and acrosome reaction. As such, we have documented the relationship between sperm quality and the distribution of sperm RNAs by showing divergent levels of transcripts encoding for proteins involved in either nuclear condensation （protamines 1 and 2） or in capacitation （eNOS and nNOS, c-myc） or in motility and sperm survival （aromatase） between low and high motile sperm issued from the same sample. Therefore, analyzing the profile of mRNAs could be helpful either as a diagnostic tool for evaluating male fertility after spermatogenesis or for prognosis use for fertilization.

关键词： chromatin fertility gamete quality man spermatozoa transcripts