scholarly journals Promyelocytic leukemia nuclear bodies associate with transcriptionally active genomic regions

2004 ◽  
Vol 164 (4) ◽  
pp. 515-526 ◽  
Author(s):  
Jayson Wang ◽  
Carol Shiels ◽  
Peter Sasieni ◽  
Pei Jun Wu ◽  
Suhail A. Islam ◽  
...  
Keyword(s):  
X Chromosome ◽  
Transcriptional Activity ◽  
Promyelocytic Leukemia ◽  
S Phase ◽  
Nuclear Bodies ◽  
Rna Transcripts ◽  
Expression Of Genes ◽  
Inactive X Chromosome ◽  
Pml Bodies ◽  
Genomic Regions

The promyelocytic leukemia (PML) protein is aggregated into nuclear bodies that are associated with diverse nuclear processes. Here, we report that the distance between a locus and its nearest PML body correlates with the transcriptional activity and gene density around the locus. Genes on the active X chromosome are more significantly associated with PML bodies than their silenced homologues on the inactive X chromosome. We also found that a histone-encoding gene cluster, which is transcribed only in S-phase, is more strongly associated with PML bodies in S-phase than in G0/G1 phase of the cell cycle. However, visualization of specific RNA transcripts for several genes showed that PML bodies were not themselves sites of transcription for these genes. Furthermore, knock-down of PML bodies by RNA interference did not preferentially change the expression of genes closely associated with PML bodies. We propose that PML bodies form in nuclear compartments of high transcriptional activity, but they do not directly regulate transcription of genes in these compartments.

scholarly journals Chromosomal Mcm2-7 distribution is the primary driver of the genome replication program in species from yeast to humans

2019 ◽  
Author(s):  
Eric J. Foss ◽  
Smitha Sripathy ◽  
Tonibelle Gatbonton-Schwager ◽  
Hyunchang Kwak ◽  
Adam H. Thiesen ◽  
...  
Keyword(s):  
Fission Yeast ◽  
X Chromosome ◽  
Budding Yeast ◽  
Gc Content ◽  
Replication Timing ◽  
S Phase ◽  
Genome Replication ◽  
Chromosomal Distribution ◽  
Inactive X Chromosome ◽  
Genomic Regions

AbstractThe spatio-temporal program of genome replication across eukaryotes is thought to be driven both by the uneven loading of pre-replication complexes (pre-RCs) across the genome at the onset of S-phase, and by differences in the timing of activation of these complexes during S-phase. To determine the degree to which distribution of pre-RC loading alone could account for chromosomal replication patterns, we mapped the binding sites of the Mcm2-7 helicase complex (MCM) in budding yeast, fission yeast, mouse and humans. We observed identical MCM double-hexamer footprints across the species, but notable differences in their distribution: In budding yeast, complexes were present in sharp peaks comprised largely of single double-hexamers; in fission yeast, corresponding peaks typically contained 4 to 8 double-hexamers, were more disperse, and showed a striking correlation with AT content. In mouse and humans, complexes were even more disperse, with a preference for regions of high GC content. Nonetheless, most fluctuations in replication timing in all four organisms could be accounted for by differences in chromosomal MCM distribution. This analysis also identified genomic regions whose replication timing was clearly not attributable to MCM density. The most notable was the inactive X-chromosome, which replicates late in S phase despite the fact that both MCM abundance and chromosomal distribution were comparable to those on the early replicating active X-chromosome. We conclude that, although certain genomic regions, most notably the inactive X-chromosome, are subject to post-licensing regulation, most differences in replication timing along the chromosome reflect uneven chromosomal distribution of stochastically firing pre-replication complexes.

scholarly journals Cell cycle–dependent localization of macroH2A in chromatin of the inactive X chromosome

2002 ◽  
Vol 157 (7) ◽  
pp. 1113-1123 ◽  
Author(s):  
Brian P. Chadwick ◽  
Huntington F. Willard
Keyword(s):  
Cell Cycle ◽  
X Chromosome ◽  
Degradation Pathway ◽  
S Phase ◽  
Histone H2a ◽  
The Core ◽  
Inactive X Chromosome ◽  
Inactivation Center ◽  
Chromatin Proteins ◽  
Cycle Dependent

One of several features acquired by chromatin of the inactive X chromosome (Xi) is enrichment for the core histone H2A variant macroH2A within a distinct nuclear structure referred to as a macrochromatin body (MCB). In addition to localizing to the MCB, macroH2A accumulates at a perinuclear structure centered at the centrosome. To better understand the association of macroH2A1 with the centrosome and the formation of an MCB, we investigated the distribution of macroH2A1 throughout the somatic cell cycle. Unlike Xi-specific RNA, which associates with the Xi throughout interphase, the appearance of an MCB is predominantly a feature of S phase. Although the MCB dissipates during late S phase and G2 before reforming in late G1, macroH2A1 remains associated during mitosis with specific regions of the Xi, including at the X inactivation center. This association yields a distinct macroH2A banding pattern that overlaps with the site of histone H3 lysine-4 methylation centered at the DXZ4 locus in Xq24. The centrosomal pool of macroH2A1 accumulates in the presence of an inhibitor of the 20S proteasome. Therefore, targeting of macroH2A1 to the centrosome is likely part of a degradation pathway, a mechanism common to a variety of other chromatin proteins.

scholarly journals BRCa1 participates in XIST RNa localization on inactive x chromosome

2019 ◽  
Vol 18 (2) ◽  
pp. 21-26
Author(s):  
E. A. Shestakova ◽  
T. A. Bogush
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Confocal Microscopy ◽  
X Chromosome ◽  
Fluorescent Microscopy ◽  
S Phase ◽  
Immunofluorescent Staining ◽  
Heterochromatin Protein ◽  
Inactive X Chromosome ◽  
Xist Rna

Introduction . Inactive X chromosome (Xi) is associated with noncoding XIST RNA, series of proteins and contains multiple epigenetic modifications that altogether determine a silence of the most of X-linked genes. Recently the data were obtained that tumor suppressor BRCA1 is also associated with Xi. The purpose of this study was to reveal the colocalization of BRCA1 and XIST RNA and precise spatial organization on Xi with the high resolution of confocal microscopy.Materials and methods . The object of the study is IMR90hTERT diploid immortalized fibroblast cell line. For BRCA1 and XIST RNA colocalization analysis on Xi the method of fluorescent hybridization in situ associated with immunofluorescent cell staining (immunoFISH) and confocal microscopy were used. For BRCA1 and heterochromatin protein-1 colocalization study the method of double immunofluorescent staining and common fluorescent microscopy were applied. Results . The study using confocal fluorescent microscopy with higher resolution has demonstrated at first the colocalization of BRCA1 with XIST RNA region of Xi revealed with XIST RNA probes and with replicating Xi and autosomes revealed with BrdU in late S-phase of cell cycle. Altogether, the data obtained suggest the involvement of BRCA1 in the inhibition of gene expression on Xi due to the regulation of XIST RNA association with Xi. Moreover, according to the results of confocal microscopy, BRCA1 also colocalizes with replicating Xi and autosomes revealed with BrdU in late S-phase of cell cycle. This indicates a possible involvement of this protein in the replication of pericentromeric repeats in cellular chromosomes. Colocalization of BRCA1 with heterochromatin protein-1α presented in pericentromeric regions of all chromosomes supports this suggestion.Conclusions . Altogether, the data obtained in this study suggest the involvement of BRCA1 in the inhibition of gene expression on Xi due to the association with noncoding inhibiting XIST RNA and in replication of heterochromatin regions. 

scholarly journals Promyelocytic leukemia nuclear bodies behave as DNA damage sensors whose response to DNA double-strand breaks is regulated by NBS1 and the kinases ATM, Chk2, and ATR

2006 ◽  
Vol 175 (1) ◽  
pp. 55-66 ◽  
Author(s):  
Graham Dellaire ◽  
Reagan W. Ching ◽  
Kashif Ahmed ◽  
Farid Jalali ◽  
Kenneth C.K. Tse ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cellular Response ◽  
Cell Cycle Progression ◽  
Nuclear Body ◽  
Promyelocytic Leukemia ◽  
S Phase ◽  
Nuclear Bodies ◽  
Structural Basis ◽  
Loss Of Function

The promyelocytic leukemia (PML) nuclear body (NB) is a dynamic subnuclear compartment that is implicated in tumor suppression, as well as in the transcription, replication, and repair of DNA. PML NB number can change during the cell cycle, increasing in S phase and in response to cellular stress, including DNA damage. Although topological changes in chromatin after DNA damage may affect the integrity of PML NBs, the molecular or structural basis for an increase in PML NB number has not been elucidated. We demonstrate that after DNA double-strand break induction, the increase in PML NB number is based on a biophysical process, as well as ongoing cell cycle progression and DNA repair. PML NBs increase in number by a supramolecular fission mechanism similar to that observed in S-phase cells, and which is delayed or inhibited by the loss of function of NBS1, ATM, Chk2, and ATR kinase. Therefore, an increase in PML NB number is an intrinsic element of the cellular response to DNA damage.

scholarly journals Painting of Fourth and the X-Linked 1.688 Satellite in D. melanogaster Is Involved in Chromosome-Wide Gene Regulation

Cells ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 323
Author(s):  
Samaneh Ekhteraei-Tousi ◽  
Jacob Lewerentz ◽  
Jan Larsson
Keyword(s):  
X Chromosome ◽  
Dosage Compensation ◽  
Rapid Evolution ◽  
Regulatory Mechanisms ◽  
Expression Of Genes ◽  
Male Specific Lethal ◽  
Msl Complex ◽  
Specific Regulation ◽  
Male Specific ◽  
Genomic Regions

Chromosome-specific regulatory mechanisms provide a model to understand the coordinated regulation of genes on entire chromosomes or on larger genomic regions. In fruit flies, two chromosome-wide systems have been characterized: The male-specific lethal (MSL) complex, which mediates dosage compensation and primarily acts on the male X-chromosome, and Painting of fourth (POF), which governs chromosome-specific regulation of genes located on the 4th chromosome. How targeting of one specific chromosome evolves is still not understood; but repeated sequences, in forms of satellites and transposable elements, are thought to facilitate the evolution of chromosome-specific targeting. The highly repetitive 1.688 satellite has been functionally connected to both these systems. Considering the rapid evolution and the necessarily constant adaptation of regulatory mechanisms, such as dosage compensation, we hypothesised that POF and/or 1.688 may still show traces of dosage-compensation functions. Here, we test this hypothesis by transcriptome analysis. We show that loss of Pof decreases not only chromosome 4 expression but also reduces the X-chromosome expression in males. The 1.688 repeat deletion, Zhr1 (Zygotic hybrid rescue), does not affect male dosage compensation detectably; however, Zhr1 in females causes a stimulatory effect on X-linked genes with a strong binding affinity to the MSL complex (genes close to high-affinity sites). Lack of pericentromeric 1.688 also affected 1.688 expression in trans and was linked to the differential expression of genes involved in eggshell formation. We discuss our results with reference to the connections between POF, the 1.688 satellite and dosage compensation, and the role of the 1.688 satellite in hybrid lethality.

scholarly journals Acute promyelocytic leukemia, arsenic, and PML bodies

2012 ◽  
Vol 198 (1) ◽  
pp. 11-21 ◽  
Author(s):  
Hugues de Thé ◽  
Morgane Le Bras ◽  
Valérie Lallemand-Breitenbach
Keyword(s):  
Oxidative Stress ◽  
Retinoic Acid ◽  
Fusion Protein ◽  
Acute Promyelocytic Leukemia ◽  
Nuclear Receptor ◽  
Chromosomal Translocation ◽  
Promyelocytic Leukemia ◽  
Nuclear Bodies ◽  
Disease Pathogenesis ◽  
Pml Bodies

Acute promyelocytic leukemia (APL) is driven by a chromosomal translocation whose product, the PML/retinoic acid (RA) receptor α (RARA) fusion protein, affects both nuclear receptor signaling and PML body assembly. Dissection of APL pathogenesis has led to the rediscovery of PML bodies and revealed their role in cell senescence, disease pathogenesis, and responsiveness to treatment. APL is remarkable because of the fortuitous identification of two clinically effective therapies, RA and arsenic, both of which degrade PML/RARA oncoprotein and, together, cure APL. Analysis of arsenic-induced PML or PML/RARA degradation has implicated oxidative stress in the biogenesis of nuclear bodies and SUMO in their degradation.

X chromosome reactivation in mouse embryonal carcinoma cells

1985 ◽  
Vol 5 (10) ◽  
pp. 2705-2712
Author(s):  
G D Paterno ◽  
C N Adra ◽  
M W McBurney
Keyword(s):  
X Chromosome ◽  
Dna Sequences ◽  
Transcriptional Repression ◽  
Embryonal Carcinoma ◽  
S Phase ◽  
Dna Demethylation ◽  
Embryonal Carcinoma Cell ◽  
X Chromosomes ◽  
Embryonal Carcinoma Cell Line ◽  
Inactive X Chromosome

The embryonal carcinoma cell line, C86S1, carries two X chromosomes, one of which replicates late during S phase of the cell cycle and appears to be genetically inactive. C86S1A1 is a mutant which lacks activity of the X-encoded enzyme, hypoxanthine phosphoribosyltransferase (HPRT). Treatment of C86S1A1 cells with DNA-demethylating agents, such as 5-azacytidine (5AC), resulted in (i) the transient expression in almost all cells of elevated levels of HPRT and three other enzymes encoded by X-linked genes and (ii) the stable expression of HPRT in up to 5 to 20% of surviving cells. Most cells which stably expressed HPRT had two X chromosomes which replicated in early S phase. C86S1A1 cells which had lost the inactive X chromosome did not respond to 5AC. These results suggest that DNA demethylation results in the reactivation of genes on the inactive X chromosome and perhaps in the reactivation of the entire X chromosome. No such reactivation occurred in C86S1A1 cells when the cells were differentiated before exposure to 5AC. Thus, the process of X chromosome inactivation may be a sequential one involving, as a first step, methylation of certain DNA sequences and, as a second step, some other mechanism(s) of transcriptional repression.

scholarly journals X chromosome reactivation in mouse embryonal carcinoma cells.

1985 ◽  
Vol 5 (10) ◽  
pp. 2705-2712 ◽  
Author(s):  
G D Paterno ◽  
C N Adra ◽  
M W McBurney
Keyword(s):  
X Chromosome ◽  
Dna Sequences ◽  
Transcriptional Repression ◽  
Embryonal Carcinoma ◽  
S Phase ◽  
Dna Demethylation ◽  
Embryonal Carcinoma Cell ◽  
X Chromosomes ◽  
Embryonal Carcinoma Cell Line ◽  
Inactive X Chromosome

The embryonal carcinoma cell line, C86S1, carries two X chromosomes, one of which replicates late during S phase of the cell cycle and appears to be genetically inactive. C86S1A1 is a mutant which lacks activity of the X-encoded enzyme, hypoxanthine phosphoribosyltransferase (HPRT). Treatment of C86S1A1 cells with DNA-demethylating agents, such as 5-azacytidine (5AC), resulted in (i) the transient expression in almost all cells of elevated levels of HPRT and three other enzymes encoded by X-linked genes and (ii) the stable expression of HPRT in up to 5 to 20% of surviving cells. Most cells which stably expressed HPRT had two X chromosomes which replicated in early S phase. C86S1A1 cells which had lost the inactive X chromosome did not respond to 5AC. These results suggest that DNA demethylation results in the reactivation of genes on the inactive X chromosome and perhaps in the reactivation of the entire X chromosome. No such reactivation occurred in C86S1A1 cells when the cells were differentiated before exposure to 5AC. Thus, the process of X chromosome inactivation may be a sequential one involving, as a first step, methylation of certain DNA sequences and, as a second step, some other mechanism(s) of transcriptional repression.

The promyelocytic leukemia nuclear body: sites of activity?

2002 ◽  
Vol 80 (3) ◽  
pp. 301-310 ◽  
Author(s):  
Christopher H Eskiw ◽  
David P Bazett-Jones
Keyword(s):  
Retinoic Acid Receptor ◽  
Eukaryotic Cell ◽  
Nuclear Body ◽  
Promyelocytic Leukemia ◽  
Nuclear Bodies ◽  
Leukemic Cells ◽  
Pml Bodies ◽  
Nuclear Events ◽  
Cellular Stresses

The promyelocytic leukemia (PML) nuclear body is one of many subnuclear domains in the eukaryotic cell nucleus. It has received much attention in the past few years because it accumulates the promyelocytic leukemia protein called PML. This protein is implicated in many nuclear events and is found as a fusion with the retinoic acid receptor RARα in leukemic cells. The importance of PML bodies in cell differentiation and growth is implicated in acute promyelocitic leukemia cells, which do not contain PML bodies. Treatment of patients with drugs that reverse the disease phenotype also causes PML bodies to reform. In this review, we discuss the structure, composition, and dynamics that may provide insights into the function of PML bodies. We also discuss the repsonse of PML bodies to cellular stresses, such as virus infection and heat shock. We interpret the changes that occur as evidence for a role of these structures in gene transcription. We also examine the role of the posttranslational modification, SUMO-1 addition, in directing proteins to this nuclear body. Characterization of the mobility of PML body associated proteins further supports a role in specific nuclear events, rather than the bodies resulting from random accumulations of proteins.Key words: promyelocytic leukemia, nucleus, transcription, nuclear bodies.

scholarly journals Allele-specific non-CG DNA methylation marks domains of active chromatin in female mouse brain

2017 ◽  
Vol 114 (14) ◽  
pp. E2882-E2890 ◽  
Author(s):  
Christopher L. Keown ◽  
Joel B. Berletch ◽  
Rosa Castanon ◽  
Joseph R. Nery ◽  
Christine M. Disteche ◽  
...  
Keyword(s):  
Dna Methylation ◽  
X Chromosome ◽  
Transcriptional Repression ◽  
Transcriptional Activity ◽  
Specific Gene ◽  
Epigenetic Mark ◽  
Gene Promoters ◽  
X Chromosomes ◽  
Inactive X Chromosome ◽  
Allele Specific

DNA methylation at gene promoters in a CG context is associated with transcriptional repression, including at genes silenced on the inactive X chromosome in females. Non-CG methylation (mCH) is a distinct feature of the neuronal epigenome that is differentially distributed between males and females on the X chromosome. However, little is known about differences in mCH on the active (Xa) and inactive (Xi) X chromosomes because stochastic X-chromosome inactivation (XCI) confounds allele-specific epigenomic profiling. We used whole-genome bisulfite sequencing in a mouse model with nonrandom XCI to examine allele-specific DNA methylation in frontal cortex. Xi was largely devoid of mCH, whereas Xa contained abundant mCH similar to the male X chromosome and the autosomes. In contrast to the repressive association of DNA methylation at CG dinucleotides (mCG), mCH accumulates on Xi in domains with transcriptional activity, including the bodies of most genes that escape XCI and at the X-inactivation center, validating this epigenetic mark as a signature of transcriptional activity. Escape genes showing CH hypermethylation were the only genes with CG-hypomethylated promoters on Xi, a well-known mark of active transcription. Finally, we found extensive allele-specific mCH and mCG at autosomal imprinted regions, some with a negative correlation between methylation in the two contexts, further supporting their distinct functions. Our findings show that neuronal mCH functions independently of mCG and is a highly dynamic epigenomic correlate of allele-specific gene regulation.

Sign in / Sign up

Export Citation Format

Share Document