scholarly journals Prothymosin α is a chromatin-remodelling protein in mammalian cells

1998 ◽  
Vol 333 (1) ◽  
pp. 1-3 ◽  
Author(s):  
Jaime GÓMEZ-MÁRQUEZ ◽  
Pilar RODRÍGUEZ
Keyword(s):  
Mammalian Cells ◽  
Nuclear Protein ◽  
Nuclease Activity ◽  
Histone H1 ◽  
Micrococcal Nuclease ◽  
Active Chromatin ◽  
Dna Ladder ◽  
Prothymosin Α ◽  
Histone Octamer ◽  
Dna Fragment

Prothymosin α (ProTα) is an abundant mammalian acidic nuclear protein whose expression is related to cell proliferation. Here we report that in HL-60 cells overexpressing ProTα, the accessibility of micrococcal nuclease to chromatin is strongly increased. In the DNA ladder generated by the nuclease activity, the sizes of the mononucleosome (146 bp, the DNA fragment that is bound to the histone octamer) and its multimers correspond to nucleosomes lacking histone H1. The percentage of histone-H1-depleted chromatin (active chromatin) is also higher in the cells overexpressing ProTα. On the basis of these and previous findings, we propose a biological role for ProTα in the remodelling of chromatin fibres through its interaction with histone H1.

scholarly journals Overexpression of prothymosin α accelerates proliferation and retards differentiation in HL-60 cells

1998 ◽  
Vol 331 (3) ◽  
pp. 753-761 ◽  
Author(s):  
Pilar RODRÍGUEZ ◽  
Juan E. VIÑUELA ◽  
Leoncio ÁLVAREZ-FERNÁNDEZ ◽  
Montserrat BUCETA ◽  
Anxo VIDAL ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Opposite Effect ◽  
Cellular Proliferation ◽  
Nuclear Protein ◽  
Prothymosin Α ◽  
Mammalian Cell Lines ◽  
Antisense Orientation ◽  
Cell Clones ◽  
Proliferation And Differentiation ◽  
Antisense Construct

Prothymosin α (ProTα) is an acidic nuclear protein the expression of which is related to the proliferation and differentiation processes in mammalian cells. In the present study we have stably transfected HL-60 cells, a biological system that allows the study of both proliferation and differentiation, with recombinant vectors encoding sense and antisense ProTα mRNA. In the HL-60 cell clones overexpressing ProTα we observed an acceleration in the growth rate, whereas expression of the antisense orientation showed the opposite effect. Moreover, cell-cycle analysis demonstrated that the G1-phase was shortened in the cells expressing the sense construct. Before studying how ProTα affects differentiation, we showed that the down-regulation of ProTα gene during differentiation occurs in all mammalian cell lines (HL-60, K562, U937, MEL C88, N2A and PC12) analysed. The biological effect evoked by the induction of the ProTα sense vector was the retardation of cell differentiation, although expression of the antisense construct showed no effect on differentiation. In conclusion, our findings provide evidence that ProTα is directly implicated in cellular proliferation and that the maintenance of high levels of ProTα inside HL-60 cells is incompatible with their ability to differentiate.

scholarly journals Site-specific ubiquitylation acts as a regulator of linker histone H1

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Eva Höllmüller ◽  
Simon Geigges ◽  
Marie L. Niedermeier ◽  
Kai-Michael Kammer ◽  
Simon M. Kienle ◽  
...  
Keyword(s):  
Posttranslational Modifications ◽  
Histone H1 ◽  
Linker Histone ◽  
Active Chromatin ◽  
Site Specific ◽  
Linker Histone H1 ◽  
Fundamental Process ◽  
Core Histones ◽  
Wide Scale

AbstractDecoding the role of histone posttranslational modifications (PTMs) is key to understand the fundamental process of epigenetic regulation. This is well studied for PTMs of core histones but not for linker histone H1 in general and its ubiquitylation in particular due to a lack of proper tools. Here, we report on the chemical synthesis of site-specifically mono-ubiquitylated H1.2 and identify its ubiquitin-dependent interactome on a proteome-wide scale. We show that site-specific ubiquitylation of H1 at position K64 modulates interactions with deubiquitylating enzymes and the deacetylase SIRT1. Moreover, it affects H1-dependent chromatosome assembly and phase separation resulting in a more open chromatosome conformation generally associated with a transcriptionally active chromatin state. In summary, we propose that site-specific ubiquitylation plays a general regulatory role for linker histone H1.

scholarly journals Dissection of acute stimulus-inducible nucleosome remodeling in mammalian cells

2019 ◽  
Author(s):  
Federico Comoglio ◽  
Marta Simonatto ◽  
Sara Polletti ◽  
Xin Liu ◽  
Stephen T. Smale ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Regulatory Elements ◽  
Micrococcal Nuclease ◽  
Nucleosome Remodeling ◽  
Nucleosome Dynamics ◽  
Nucleosome Organization ◽  
Regulatory Information ◽  
Different Types ◽  
Genomic Regions ◽  
The Impact

ABSTRACTAccessibility of the genomic regulatory information is largely controlled by the nucleosome-organizing activity of transcription factors (TFs). Whereas stimulus-induced TFs bind to genomic regions that are maintained accessible by lineage-determining TFs, they also increase accessibility of thousands of cis-regulatory elements. Nucleosome remodeling events underlying such changes and their interplay with basal positioning are unknown. Here, we devised a novel quantitative framework discriminating different types of nucleosome remodeling events in micrococcal nuclease ChIP-seq datasets and used it to analyze nucleosome dynamics at stimulus-regulated cis-regulatory elements. At enhancers, remodeling preferentially affected poorly positioned nucleosomes while sparing well-positioned nucleosomes flanking the enhancer core, indicating that inducible TFs do not suffice to overrule basal nucleosomal organization maintained by lineage-determining TFs. Remodeling events appeared to be combinatorially driven by multiple TFs, with distinct TFs showing however different remodeling efficiencies. Overall, these data provide a systematic view of the impact of stimulation on nucleosome organization and genome accessibility in mammalian cells.

scholarly journals Histone H1 and transcriptionally active chromatin regions

1985 ◽  
Vol 1 (3) ◽  
pp. 141-146
Author(s):  
A. A. Karavanov
Keyword(s):  
Histone H1 ◽  
Active Chromatin

scholarly journals Footprinting studies on the effect of echinomycin on the structure of a bent DNA fragment

1990 ◽  
Vol 269 (1) ◽  
pp. 217-221 ◽  
Author(s):  
K R Fox ◽  
E Kentebe
Keyword(s):  
Binding Sites ◽  
Dna Structure ◽  
Drug Binding ◽  
Micrococcal Nuclease ◽  
Kinetoplast Dna ◽  
Bent Dna ◽  
Diethyl Pyrocarbonate ◽  
Drug Binding Sites ◽  
Dna Fragment

The interaction of echinomycin with a kinetoplast DNA fragment which contains phased runs of adenine residues has been examined by various footprinting techniques. DNAase I footprinting confirms that all drug-binding sites contain the dinucleotide CpG. However, not all such sequences are protected. Three sites, each of which is located between two adenine tracks in the sequence GCGA, are not protected from DNAase I attack. Enhanced cleavage by DNAase I, DNAase II and micrococcal nuclease is observed in regions surrounding drug-binding sites. The results suggest that echinomycin alters the conformation of the AT tracks, making them more like an average DNA structure. Echinomycin renders adenine residues in the sequence CGA hyper-reactive to diethyl pyrocarbonate.

Histone H1 Interacts Preferentially with DNA Fragments Containing a Cisplatin- Induced 1,2-Intrastrand Cross-Link

2007 ◽  
Vol 62 (11-12) ◽  
pp. 905-908 ◽  
Author(s):  
Julia N. Yaneva ◽  
Elena G. Paneva ◽  
Siyka I. Zacharieva ◽  
Jordanka Zlatanova
Keyword(s):  
Experimental Data ◽  
Anticancer Agents ◽  
Histone H1 ◽  
Recent Experimental Data ◽  
Band Shift ◽  
Single Target ◽  
Shift Analysis ◽  
Modified Dna ◽  
Cross Links ◽  
Dna Fragment

Cisplatin [cis-diamminedichloroplatinum(II) or cis- DDP], but not its stereoisomer transplatin, is suggested to be among the most powerful anticancer agents. It is believed that its therapeutic activity results from its interaction with DNA forming intra- and interstrand crosslinks. During our earlier investigations, we have observed a prominent preference of the linker histone H1 for binding to cis-platinated DNA (containing several different cross-links along the DNA fragment) compared with unmodified or transplatin-modified DNA. This report presents our recent experimental data obtained by band-shift analysis on the binding of H1 to a cisplatin-modified synthetic 34 bp DNA fragment containing a single target d(GG/CC) for 1,2 cis-intra-platination. Results obtained with another nuclear protein with similar DNA-binding properties, HMGB1, are also presented. The experimental data throw light on the precise preference of histone H1 for binding to different types of cisplatin-created cross-links in DNA.

scholarly journals Nuclease activity associated with mammalian mRNA in its native state: possible basis for selectivity in mRNA decay.

1990 ◽  
Vol 10 (5) ◽  
pp. 2060-2069 ◽  
Author(s):  
R Bandyopadhyay ◽  
M Coutts ◽  
A Krowczynska ◽  
G Brawerman
Keyword(s):  
Mammalian Cells ◽  
Nuclease Activity ◽  
Noncoding Region ◽  
Beta Globin ◽  
Native State ◽  
Globin Mrna ◽  
Ribosomal Subunits ◽  
Messenger Ribonucleoprotein ◽  
Mouse Sarcoma ◽  
Actin Mrna

Polysome and messenger ribonucleoprotein (mRNP) preparations from various mammalian cells contain tightly bound nuclease activity that causes degradation of the mRNA in the preparations. This activity was found to cosediment with all polysome size classes as well as with free mRNPs and to remain associated with the mRNPs released from polysomes by treatment with EDTA. No association with ribosomal subunits was evident. The rates of mRNA degradation were not affected by serial dilution, an indication that enzyme and substrate are tightly associated. beta-Globin mRNA in purified reticulocyte polysomes was cleaved at AU sequences in the 3'-terminal region. Cleavages at the same sites occurred when deproteinized reticulocyte RNA was incubated with mouse sarcoma 180 (S-180) polysomes. The S-180 preparations caused additional cleavages, primarily at UG sequences. A P40 mRNA in S-180 polysomes was cleaved primarily in the 3' noncoding region, but the cleavages in a P21 mRNA were seen in the 5' noncoding region only. Actin mRNA was cleaved in an internal region, yielding large relatively stable 3'- and 5'-terminal fragments. These data suggest the occurrence of highly specific interactions between one or more mRNA-bound nucleases and individual mRNA species.

scholarly journals Histone H1 Is Dispensable for Methylation-Associated Gene Silencing in Ascobolus immersusand Essential for Long Life Span

2000 ◽  
Vol 20 (1) ◽  
pp. 61-69 ◽  
Author(s):  
Jose L. Barra ◽  
Laïla Rhounim ◽  
Jean-Luc Rossignol ◽  
Godeleine Faugeron
Keyword(s):  
Gene Silencing ◽  
Life Span ◽  
Sequence Similarity ◽  
Histone H1 ◽  
Peptide Sequence ◽  
Micrococcal Nuclease ◽  
Gene Encoding ◽  
H1 Histone ◽  
Mutant Strains ◽  
Long Life

ABSTRACT A gene encoding a protein that shows sequence similarity with the histone H1 family only was cloned in Ascobolus immersus. The deduced peptide sequence presents the characteristic three-domain structure of metazoan linker histones, with a central globular region, an N-terminal tail, and a long positively charged C-terminal tail. By constructing an artificial duplication of this gene, namedH1, it was possible to methylate and silence it by the MIP (methylation induced premeiotically) process. This resulted in the complete loss of the Ascobolus H1 histone. Mutant strains lacking H1 displayed normal methylation-associated gene silencing, underwent MIP, and showed the same methylation-associated chromatin modifications as did wild-type strains. However, they displayed an increased accessibility of micrococcal nuclease to chromatin, whether DNA was methylated or not, and exhibited a hypermethylation of the methylated genome compartment. These features are taken to imply thatAscobolus H1 histone is a ubiquitous component of chromatin which plays no role in methylation-associated gene silencing. Mutant strains lacking histone H1 reproduced normally through sexual crosses and displayed normal early vegetative growth. However, between 6 and 13 days after germination, they abruptly and consistently stopped growing, indicating that Ascobolus H1 histone is necessary for long life span. This constitutes the first observation of a physiologically important phenotype associated with the loss of H1.

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