Parathymosin Affects the Binding of Linker Histone H1 to Nucleosomes and Remodels Chromatin Structure

Linker histone H1 is the major factor that stabilizes higher order chromatin structure and modulates the action of chromatin-remodeling enzymes. We have previously shown that parathymosin, an acidic, nuclear protein binds to histone H1in vitroandin vivo. Confocal laser scanning microscopy reveals a nuclear punctuate staining of the endogenous protein in interphase cells, which is excluded from dense heterochromatic regions. Using anin vitrochromatin reconstitution system under physiological conditions, we show here that parathymosin (ParaT) inhibits the binding of H1 to chromatin in a dose-dependent manner. Consistent with these findings, H1-containing chromatin assembled in the presence of ParaT has reduced nucleosome spacing. These observations suggest that interaction of the two proteins might result in a conformational change of H1. Fluorescence spectroscopy and circular dichroism-based measurements on mixtures of H1 and ParaT confirm this hypothesis. Human sperm nuclei challenged with ParaT become highly decondensed, whereas overexpression of green fluorescent protein- or FLAG-tagged protein in HeLa cells induces global chromatin decondensation and increases the accessibility of chromatin to micrococcal nuclease digestion. Our data suggest a role of parathymosin in the remodeling of higher order chromatin structure through modulation of H1 interaction with nucleosomes and point to its involvement in chromatin-dependent functions.

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Topoisomerase II, scaffold component, promotes chromatin compaction in vitro in a linker-histone H1-dependent manner

Nucleic Acids Research ◽

10.1093/nar/gkm116 ◽

2007 ◽

Vol 35 (8) ◽

pp. 2787-2799 ◽

Cited By ~ 27

Author(s):

Kohji Hizume ◽

Sumiko Araki ◽

Kenichi Yoshikawa ◽

Kunio Takeyasu

Keyword(s):

Topoisomerase Ii ◽

Histone H1 ◽

Linker Histone ◽

Dependent Manner ◽

Chromatin Compaction ◽

Linker Histone H1

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Influence of linker histone H1 on chromatin remodeling

Biochemistry and Cell Biology ◽

10.1139/o01-098 ◽

2001 ◽

Vol 79 (3) ◽

pp. 317-324 ◽

Cited By ~ 23

Author(s):

David A Hill

Keyword(s):

Key Words ◽

Chromatin Remodeling ◽

Chromatin Structure ◽

Central Area ◽

Histone H1 ◽

Higher Order ◽

Linker Histone ◽

Linker Histone H1 ◽

Chromatin Remodeling Complexes ◽

Cellular Dna

Chromatin-remodeling complexes have been a central area of focus for research dealing with accessing cellular DNA sequestered in chromatin. Although the linker histone H1 plays a major role in promoting and maintaining higher-order chromatin structure, it has been noticeably absent from assays utilizing chromatin-remodeling enzymes. This review focuses on two ATP-dependent chromatin-remodeling complexes, Drosophila ISWI and mammalian SWI/SNF, that have been assayed using chromatin templates containing histone H1.Key words: SWI/SNF, ISWI, chromatin remodeling, histone H1.

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Phosphorylation and an ATP-dependent process increase the dynamic exchange of H1 in chromatin

The Journal of Cell Biology ◽

10.1083/jcb.200202131 ◽

2002 ◽

Vol 158 (7) ◽

pp. 1161-1170 ◽

Cited By ~ 65

Author(s):

Yali Dou ◽

Josephine Bowen ◽

Yifan Liu ◽

Martin A. Gorovsky

Keyword(s):

Negative Charge ◽

Histone H1 ◽

Linker Histone ◽

Global Effect ◽

Dynamic Binding ◽

Linker Histone H1 ◽

Dependent Process ◽

Dynamic Exchange

In Tetrahymena cells, phosphorylation of linker histone H1 regulates transcription of specific genes. Phosphorylation acts by creating a localized negative charge patch and phenocopies the loss of H1 from chromatin, suggesting that it affects transcription by regulating the dissociation of H1 from chromatin. To test this hypothesis, we used FRAP of GFP-tagged H1 to analyze the effects of mutations that either eliminate or mimic phosphorylation on the binding of H1 to chromatin both in vivo and in vitro. We demonstrate that phosphorylation can increase the rate of dissociation of H1 from chromatin, providing a mechanism by which it can affect H1 function in vivo. We also demonstrate a previously undescribed ATP-dependent process that has a global effect on the dynamic binding of linker histone to chromatin.

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Bacterial lipopolysaccharides variably modulate in vitro biofilm formation of Candida species

Journal of Medical Microbiology ◽

10.1099/jmm.0.021832-0 ◽

2010 ◽

Vol 59 (10) ◽

pp. 1225-1234 ◽

Cited By ~ 51

Author(s):

H. M. H. N. Bandara ◽

O. L. T. Lam ◽

R. M. Watt ◽

L. J. Jin ◽

L. P. Samaranayake

Keyword(s):

Biofilm Formation ◽

Laser Scanning ◽

Significant Inhibition ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Dependent Manner ◽

Bacterial Lipopolysaccharides ◽

Species Specific ◽

Biofilm Development

The objective of this study was to evaluate the effect of the bacterial endotoxin LPS on Candida biofilm formation in vitro. The effect of the LPS of Pseudomonas aeruginosa, Klebsiella pneumoniae, Serratia marcescens and Salmonella typhimurium on six different species of Candida, comprising Candida albicans ATCC 90028, Candida glabrata ATCC 90030, Candida krusei ATCC 6258, Candida tropicalis ATCC 13803, Candida parapsilosis ATCC 22019 and Candida dubliniensis MYA 646, was studied using a standard biofilm assay. The metabolic activity of in vitro Candida biofilms treated with LPS at 90 min, 24 h and 48 h was quantified by XTT reduction assay. Viable biofilm-forming cells were qualitatively analysed using confocal laser scanning microscopy (CLSM), while scanning electron microscopy (SEM) was employed to visualize the biofilm structure. Initially, adhesion of C. albicans was significantly stimulated by Pseudomonas and Klebsiella LPS. A significant inhibition of Candida adhesion was noted for the following combinations: C. glabrata with Pseudomonas LPS, C. tropicalis with Serratia LPS, and C. glabrata, C. parapsilosis or C. dubliniensis with Salmonella LPS (P<0.05). After 24 h of incubation, a significant stimulation of initial colonization was noted for the following combinations: C. albicans/C. glabrata with Klebsiella LPS, C. glabrata/C. tropicalis/C. krusei with Salmonella LPS. In contrast, a significant inhibition of biofilm formation was observed in C. glabrata/C. dubliniensis/C. krusei with Pseudomonas LPS, C. krusei with Serratia LPS, C. dubliniensis with Klebsiella LPS and C. parapsilosis/C. dubliniensis /C. krusei with Salmonella LPS (P<0.05). On further incubation for 48 h, a significant enhancement of biofilm maturation was noted for the following combinations: C. glabrata/C. tropicalis with Serratia LPS, C. dubliniensis with Klebsiella LPS and C. glabrata with Salmonella LPS, and a significant retardation was noted for C. parapsilosis/C. dubliniensis/C. krusei with Pseudomonas LPS, C. tropicalis with Serratia LPS, C. glabrata/C. parapsilosis/C. dubliniensis with Klebsiella LPS and C. dubliniensis with Salmonella LPS (P<0.05). These findings were confirmed by SEM and CLSM analyses. In general, the inhibition of the biofilm development of LPS-treated Candida spp. was accompanied by a scanty architecture with a reduced numbers of cells compared with the profuse and densely colonized control biofilms. These data are indicative that bacterial LPSs modulate in vitro Candida biofilm formation in a species-specific and time-dependent manner. The clinical and the biological relevance of these findings have yet to be explored.

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Susceptibility of Mature Staphylococcus Biofilms to Chinese Herbal Decoction Sanhuang Jiedu: An In Vitro Study

BioMed Research International ◽

10.1155/2020/7473942 ◽

2020 ◽

Vol 2020 ◽

pp. 1-10

Author(s):

Shaoe Zhang ◽

Xiao Wang ◽

Xiaotao Shi ◽

Honglue Tan ◽

Himanshu Garg

Keyword(s):

Laser Scanning ◽

Multidrug Resistant ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Control Group ◽

Antibiofilm Activity ◽

Dependent Manner ◽

Chinese Herbal ◽

Titanium Surfaces

Background. External socking and washing with the Chinese herbal Sanhuang Jiedu decoction (SHJD) can effectively control local limb infections with bone and implant exposure. However, the antibiofilm activities of this decoction in vitro have not yet been investigated. Therefore, the aim of this study was to examine the effects and characteristics of SHJD on the mature biofilms of multidrug-resistant staphylococci on a titanium surface. Methods. Biofilm-forming methicillin-resistant Staphylococcus epidermidis ATCC 35984 and S. aureus ATCC 43330, and non-biofilm-forming S. epidermidis ATCC 12228 were selected as the experimental strains. The mature biofilms were prepared on titanium surfaces. The five experimental groups were based on dilution concentrations (DC) of SHJD: the control group (biofilm incubated with 0.85% NaCl solution), the SHJD (DC:1/8) group (initial SHJD solution was diluted 1/8), the SHJD (DC:1/4) group, the SHJD (DC:1/2) group, and the SHJD (DC:1/1) group (initial SHJD solution). The effects of SHJD on the mature biofilms were observed with the bacterial spread plate method, crystal violet (CV) staining, scanning electron microscopy, and confocal laser scanning microscopy. Results. After culture in tryptic soy broth for 72 h, ATCC 43300 and ATCC 35984 produced mature biofilms and ATCC 12228 did not. The optical density value of ATCC 12228 was 0.11 ± 0.02 , significantly lower than that of ATCC 35984 ( 0.42 ± 0.05 ) or ATCC 43300 ( 0.41 ± 0.03 ) ( P < 0.05 ). The mature biofilms of ATCC 43300 and ATCC 35984 clearly disintegrated when incubated for 12–24 h with SHJD (DC:1/1) or SHJD (DC:1/2), showing only scattered bacterial adhesion. In the SHJD (DC:1/4) group, although many residual bacterial colonies still clustered together, presenting a biofilm structure, it was very looser than that in the SHJD (DC:1/8) group in which the biofilm was similar to that in the control group. For ATCC 12228, only colony adhesion was observed, and the number of colonies decreased as the concentration of SHJD or the culture period increased. The quantitative results for the bacterial spread plate and CV staining showed significant differences between the SHJD groups ( P < 0.05 ). Conclusion. SHJD has antibiofilm activity against multidrug-resistant Staphylococcus strains. It weakens or disrupts already-formed mature biofilms on titanium surfaces in a concentration- and incubation time-dependent manner.

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Regulation of the higher-order structure of chromatin by histones H1 and H5.

The Journal of Cell Biology ◽

10.1083/jcb.90.2.279 ◽

1981 ◽

Vol 90 (2) ◽

pp. 279-288 ◽

Cited By ~ 80

Author(s):

J Allan ◽

G J Cowling ◽

N Harborne ◽

P Cattini ◽

R Craigie ◽

...

Keyword(s):

Spatial Organization ◽

Single Species ◽

Histone H1 ◽

Higher Order ◽

Linker Histone ◽

Micrococcal Nuclease ◽

Order Structure ◽

Chicken Erythrocyte ◽

Base Pairs ◽

Native Chicken

Chicken erythrocyte chromatins containing a single species of linker histone, H1 or H5, have been prepared, using reassembly techniques developed previously. The reconstituted complexes possess the conformation of native chicken erythrocyte chromatin, as judged by chemical and structural criteria; saturation is reached when two molecules of linker histone are bound per nucleosome, as in native erythrocyte chromatin, which the resulting material resembles in its appearance in the electron microscope and quantitatively in its linear condensation factor relative to free DNA. The periodicity of micrococcal nuclease-sensitive sites in the linker regions associated with histone H1 or H5 is 10.4 base pairs, suggesting that the spatial organization of the linker region in the higher-order structure of chromatin is similar to that in isolated nucleosomes. The susceptible sites are cut at differing frequencies, as previously found for the nucleosome cores, leading to a characteristic distribution of intensities in the digests. The scission frequency of sites in the linker DNA depends additionally on the identity of the linker histone, suggesting that the higher-order structure is subject to secondary modulation by the associated histones.

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Pin1 promotes histone H1 dephosphorylation and stabilizes its binding to chromatin

The Journal of Cell Biology ◽

10.1083/jcb.201305159 ◽

2013 ◽

Vol 203 (1) ◽

pp. 57-71 ◽

Cited By ~ 26

Author(s):

Nikhil Raghuram ◽

Hilmar Strickfaden ◽

Darin McDonald ◽

Kylie Williams ◽

He Fang ◽

...

Keyword(s):

Rna Polymerase Ii ◽

Chromatin Structure ◽

Transcriptional Activation ◽

Binding Sites ◽

Histone H1 ◽

Dependent Manner ◽

Prolyl Isomerase ◽

Proline Isomerization ◽

The Stability

Histone H1 plays a crucial role in stabilizing higher order chromatin structure. Transcriptional activation, DNA replication, and chromosome condensation all require changes in chromatin structure and are correlated with the phosphorylation of histone H1. In this study, we describe a novel interaction between Pin1, a phosphorylation-specific prolyl isomerase, and phosphorylated histone H1. A sub-stoichiometric amount of Pin1 stimulated the dephosphorylation of H1 in vitro and modulated the structure of the C-terminal domain of H1 in a phosphorylation-dependent manner. Depletion of Pin1 destabilized H1 binding to chromatin only when Pin1 binding sites on H1 were present. Pin1 recruitment and localized histone H1 phosphorylation were associated with transcriptional activation independent of RNA polymerase II. We thus identify a novel form of histone H1 regulation through phosphorylation-dependent proline isomerization, which has consequences on overall H1 phosphorylation levels and the stability of H1 binding to chromatin.

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Synthesis and in vitro biochemical evaluation of oxime bond-linked daunorubicin–GnRH-III conjugates developed for targeted drug delivery

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.14.64 ◽

2018 ◽

Vol 14 ◽

pp. 756-771 ◽

Cited By ~ 8

Author(s):

Sabine Schuster ◽

Beáta Biri-Kovács ◽

Bálint Szeder ◽

Viktor Farkas ◽

László Buday ◽

...

Keyword(s):

Antitumor Activity ◽

Cancer Cells ◽

Cellular Uptake ◽

Laser Scanning ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Dependent Manner ◽

Binding Studies ◽

Gnrh Receptors

Gonadotropin releasing hormone-III (GnRH-III), a native isoform of the human GnRH isolated from sea lamprey, specifically binds to GnRH receptors on cancer cells enabling its application as targeting moieties for anticancer drugs. Recently, we reported on the identification of a novel daunorubicin–GnRH-III conjugate (GnRH-III–[4Lys(Bu), 8Lys(Dau=Aoa)] with efficient in vitro and in vivo antitumor activity. To get a deeper insight into the mechanism of action of our lead compound, the cellular uptake was followed by confocal laser scanning microscopy. Hereby, the drug daunorubicin could be visualized in different subcellular compartments by following the localization of the drug in a time-dependent manner. Colocalization studies were carried out to prove the presence of the drug in lysosomes (early stage) and on its site of action (nuclei after 10 min). Additional flow cytometry studies demonstrated that the cellular uptake of the bioconjugate was inhibited in the presence of the competitive ligand triptorelin indicating a receptor-mediated pathway. For comparative purpose, six novel daunorubicin–GnRH-III bioconjugates have been synthesized and biochemically characterized in which 6Asp was replaced by D-Asp, D-Glu and D-Trp. In addition to the analysis of the in vitro cytostatic effect and cellular uptake, receptor binding studies with 125I-triptorelin as radiotracer and degradation of the GnRH-III conjugates in the presence of rat liver lysosomal homogenate have been performed. All derivatives showed high binding affinities to GnRH receptors and displayed in vitro cytostatic effects on HT-29 and MCF-7 cancer cells with IC50 values in a low micromolar range. Moreover, we found that the release of the active drug metabolite and the cellular uptake of the bioconjugates were strongly affected by the amino acid exchange which in turn had an impact on the antitumor activity of the bioconjugates.

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