scholarly journals Histone variant H2A.Z regulates nucleosome unwrapping and CTCF binding in mouse ES cells

2020 ◽  
Vol 48 (11) ◽  
pp. 5939-5952
Author(s):  
Zengqi Wen ◽  
Liwei Zhang ◽  
Haihe Ruan ◽  
Guohong Li

Abstract Nucleosome is the basic structural unit of chromatin, and its dynamics plays critical roles in the regulation of genome functions. However, how the nucleosome structure is regulated by histone variants in vivo is still largely uncharacterized. Here, by employing Micrococcal nuclease (MNase) digestion of crosslinked chromatin followed by chromatin immunoprecipitation (ChIP) and paired-end sequencing (MNase-X-ChIP-seq), we mapped unwrapping states of nucleosomes containing histone variant H2A.Z in mouse embryonic stem (ES) cells. We found that H2A.Z nucleosomes are more enriched with unwrapping states compared with canonical nucleosomes. Interestingly, +1 H2A.Z nucleosomes with 30–80 bp DNA is correlated with less active genes compared with +1 H2A.Z nucleosomes with 120–140 bp DNA. We confirmed the unwrapping of H2A.Z nucleosomes under native condition by re-ChIP of H2A.Z and H2A after CTCF CUT&RUN in mouse ES cells. Importantly, we found that depletion of H2A.Z results in decreased unwrapping of H3.3 nucleosomes and increased CTCF binding. Taken together, through MNase-X-ChIP-seq, we showed that histone variant H2A.Z regulates nucleosome unwrapping in vivo and that its function in regulating transcription or CTCF binding is correlated with unwrapping states of H2A.Z nucleosomes.

2008 ◽  
Vol 20 (9) ◽  
pp. 58
Author(s):  
G. R. Kafer ◽  
SA Lehnert ◽  
P. L. Kaye ◽  
R. J. Moser

Histone variants replace canonical histones in nucleosomes to serve numerous biological processes. This integration alters DNA properties to ultimately regulate gene expression. Previous mouse studies have indicated that some variants (H2AZ and H3.3) are essential for survival, but here we document and correlate histone expression patterns with key developmental events. Using quantitative reverse-transcribed PCR (qRT–PCR) we investigated the expression of 7 genes coding for H2A variants and 4 genes coding for H3 variants in mouse preimplantation embryos and in pluripotent R1 ES cells. Messenger RNA was extracted from pools of 3 embryos flushed from superovulated mice. Embryos were collected at five stages, zygotes, 2-cell embryos, morulae, blastocysts and hatching blastocysts (20 h, 44 h, 68 h, 92 h and 116 h post hCG respectively). The expression of H2A variant genes typically peaked within blastocysts. H2AZ and H2AX expression was 80 – 95% higher in blastocysts than other stages. Conversely, genes coding for H3 variants showed elevated expression in zygotes, where H3.3 expression was 85 – 95% higher and CENPA was ~75% higher than in later preimplantation stages. The expression profiles of histone remodellers SWI/SNF and CAF-1 correlated with the variants they are known to remodel (H2A and H3 variants respectively), suggesting an increased integration of those variants into nucleosomes. We also compared blastocyst and embryonic stem cell (ES cell) expression patterns. R1 ES cells express all histone variants, including H2A.Bbd, H3.1 and H3.2 which were not expressed in preimplantation embryos. Further, expression levels of every histone variant investigated differed significantly between R1 ES cells and hatching blastocysts (ANOVA, P < 0.05, n = 3 experiments). We conclude that histone variant expression reflects preimplantation developmental demands. Further, histone code expression profiles show significant change upon extended cell culture and maintenance of pluripotency as indicated by comparing in vivo hatching blastocysts to the R1 ES cell line.


2012 ◽  
Vol 24 (1) ◽  
pp. 222
Author(s):  
A. Kusanagi ◽  
J. Yamasaki ◽  
C. Iwatani ◽  
H. Tsuchiya ◽  
R. Torii

Human and mouse embryonic stem (ES) cells are derived from the inner cell mass of preimplantation blastocysts and human ES cells were long thought to be equivalent to mouse ES cells, despite clear morphological difference and different signalling pathways to maintain their pluripotency between these two ES cell types. Mouse ES cells depend on leukemia inhibitory factor (LIF) and bone morphogenic protein 4 (BMP4) signalling, whereas their human counterparts rely on basic fibroblast growth factor (bFGF) and activin A signalling. The biggest difference of two ES cells is the ability of chimera formation and mouse ES cells can contribute chimera but primate ES cells fails to do that. Monkey ES cells in primates only can be tested for chimera formation in vivo due to the ethical issue and cynomolgus monkey is the most common nonhuman primate to be used for the safety study of drug discoveries. The objective of this study was to develop novel cynomolgus monkey ES cells that have similar biological properties with mouse ES cell and our ultimate goal is to establish germline competent nonhuman primate ES cells. Ovarian stimulation and oocyte collection were carried out for the derivation of ES cells as previously described by Torii et al. Briefly, GnRH (0.9 mg/head) was administered to cynomolgus monkey and two weeks later, a micro infusion pump (iPRECIO™, Primetech Corp) contains FSH was implanted subcutaneously. Follicular aspiration was then performed 40 h after hCG injection and metaphase II oocytes were fertilized by intracytoplasmic sperm injection (ICSI). Cynomolgus monkey ES cells were then established under mouse ES cell conditions such as LIF/STAT signalling and a dome tree-dimensional (3D) morphology nonhuman primate ES cells were selected. On the other hands, ES cells that were established with the presence of basic FGF showed conventional layer-type morphology. Dome-type ES cells express pluripotent transcriptional factors such as Oct-3/4, Nonog and Sox2 as same as layer-type ES cells and both ES lines were capable of multilineage differentiations in vitro after embryoid body formation. Dome-type nonhuman ES cells can also form teratomas and differentiated into all three germ layers when grafted into immunodeficiency mice. For fluorescent gene delivery to nonhuman primate ES cells, feeder-free condition was applied and CAG-GFP vector was transfected into ES cells using Neon electroporation system (Invitrogen Inc.) for the tracing ES cells in the transplantation study. In this study, we have established dome-type ES cell lines that similar to mouse ES cells in morphology and signalling pathway. Dome-type nonhuman primate ES cells express pluripotent gene markers and prove their pluripotency both of in vitro and in vivo, in addition, these modifications would be important to create germline competent ES cells.


2017 ◽  
Author(s):  
Mariano Barbieri ◽  
Sheila Q. Xie ◽  
Elena Torlai Triglia ◽  
Inês de Santiago ◽  
Miguel R. Branco ◽  
...  

AbstractGene expression states influence the three-dimensional conformation of the genome through poorly understood mechanisms. Here, we investigate the conformation of the murine HoxB locus, a gene-dense genomic region containing closely spaced genes with distinct activation states in mouse embryonic stem (ES) cells. To predict possible folding scenarios, we performed computer simulations of polymer models informed with different chromatin occupancy features, which define promoter activation states or CTCF binding sites. Single cell imaging of the locus folding was performed to test model predictions. While CTCF occupancy alone fails to predict the in vivo folding at genomic length scale of 10 kb, we found that homotypic interactions between active and Polycomb-repressed promoters co-occurring in the same DNA fibre fully explain the HoxB folding patterns imaged in single cells. We identify state-dependent promoter interactions as major drivers of chromatin folding in gene-dense regions.


2002 ◽  
Vol 11 (4) ◽  
pp. 359-368 ◽  
Author(s):  
Dongho Choi ◽  
Hyun-Jeong Oh ◽  
Uck-Jin Chang ◽  
Soo Kyung Koo ◽  
Jean X. Jiang ◽  
...  

Embryonic stem (ES) cells have been regarded as a powerful resource for cell replacement therapy. In recent reports mouse ES cells have been successfully applied in the treatment of spinal cord injury, hereditary myelin disorder of the central nervous system, and diabetes mellitus. Another type of disease that could benefit from the availability of stem cell therapy is liver disease. However, for this potential to be realized, it is necessary to demonstrate the differentiation of ES cells into hepatocytes. To demonstrate the in vivo differentiation potential of mouse ES cells, we injected ES cells into the spleen of immunosuppressed nude mice. Histological analysis of teratomas derived from injected ES cells revealed that some areas contained typical hepatocytes arranged in a sinusoidal structure. The hepatic nature of these cells was further confirmed by showing that transcripts of liver-specific genes were present in the differentiated teratoma using reverse transcriptase-polymerase chain reaction and immunohistochemistry using several liver-specific antibodies including HEP-PAR, phenylalanine hydroxylase, and mouse N-system aminotransferase to identify the respective proteins in the differentiated hepatocytes. This is the first demonstration that mouse ES cells can differentiate in vivo into a mixed population of hepatocytes of varying maturity. This finding extends the potential use of ES cells in the cell replacement therapy by including its possible application for treating liver diseases.


Author(s):  
Sally Martin ◽  
Daniel Poppe ◽  
Nelly Olova ◽  
Conor O’Leary ◽  
Elena Ivanova ◽  
...  

AbstractDNA methylation functions in genome regulation and is implicated in neuronal maturation. Early post-natal accumulation of atypical non-CG methylation (mCH) occurs in neurons of mice and humans, but its precise function remains unknown. Here we investigate mCH deposition in neurons derived from mouse ES-cells in vitro and in cultured primary mouse neurons. We find that both acquire comparable levels of mCH over a similar period as in vivo. In vitro mCH deposition occurs concurrently with a transient increase in Dnmt3a expression, is preceded by expression of the post-mitotic neuronal marker Rbfox3 (NeuN) and is enriched at the nuclear lamina. Despite these similarities, whole genome bisulfite sequencing reveals that mCH patterning in mESC-derived neurons partially differs from in vivo. mESC-derived neurons therefore represent a valuable model system for analyzing the mechanisms and functional consequences of correct and aberrantly deposited CG and non-CG methylation in neuronal maturation.


Blood ◽  
2004 ◽  
Vol 104 (6) ◽  
pp. 1873-1880 ◽  
Author(s):  
Sebastian Carotta ◽  
Sandra Pilat ◽  
Andreas Mairhofer ◽  
Uwe Schmidt ◽  
Helmut Dolznig ◽  
...  

Abstract Differentiating embryonic stem (ES) cells are an increasingly important source of hematopoietic progenitors, useful for both basic research and clinical applications. Besides their characterization in colony assays, protocols exist for the cultivation of lymphoid, myeloid, and erythroid cells. With the possible exception of mast cells, however, long-term expansion of pure hematopoietic progenitors from ES cells has not been possible without immortalization caused by overexpression of exogenous genes. Here, we describe for the first time an efficient yet easy strategy to generate mass cultures of pure, immature erythroid progenitors from mouse ES cells (ES-EPs), using serum-free medium plus recombinant cytokines and hormones. ES-EPs represent long-lived, adult, definitive erythroid progenitors that resemble immature erythroid cells expanding in vivo during stress erythropoiesis. When exposed to terminal differentiation conditions, ES-EPs differentiated into mature, enucleated erythrocytes. Importantly, ES-EPs injected into mice did not exhibit tumorigenic potential but differentiated into normal erythrocytes. Both the virtually unlimited supply of cells and the defined culture conditions render our system a valuable tool for the analysis of factors influencing proliferation and maturation of erythroid progenitors. In addition, the system allows detailed characterization of processes during erythroid proliferation and differentiation using wild-type (wt) and genetically modified ES cells.


Development ◽  
1992 ◽  
Vol 116 (Supplement) ◽  
pp. 157-165 ◽  
Author(s):  
R. S. P. Beddington ◽  
P. Rashbass ◽  
V. Wilson

Mouse embryos that are homozygous for the Brachyury (T) deletion die at mid-gestation. They have prominent defects in the notochord, the allantois and the primitive streak. Expression of the T gene commences at the onset of gastrulation and is restricted to the primitive streak, mesoderm emerging from the streak, the head process and the notochord. Genetic evidence has suggested that there may be an increasing demand for T gene function along the rostrocaudal axis. Experiments reported here indicate that this may not be the case. Instead, the gradient in severity of the T defect may be caused by defective mesoderm cell movements, which result in a progressive accumulation of mesoderm cells near the primitive streak. Embryonic stem (ES) cells which are homozygous for the T deletion have been isolated and their differentiation in vitro and in vivo compared with that of heterozygous and wild-type ES cell lines. In +/+ ↔ T/T ES cell chimeras the Brachyury phenotype is not rescued by the presence of wild-type cells and high level chimeras show most of the features characteristic of intact T/T mutants. A few offspring from blastocysts injected with T/T ES cells have been born, several of which had greatly reduced or abnormal tails. However, little or no ES cell contribution was detectable in these animals, either as coat colour pigmentation or by isozyme analysis. Inspection of potential +/+ ↔ T/T ES cell chimeras on the 11th or 12th day of gestation, stages later than that at which intact T/T mutants die, revealed the presence of chimeras with caudal defects. These chimeras displayed a gradient of ES cell colonisation along the rostrocaudal axis with increased colonisation of caudal regions. In addition, the extent of chimerism in ectodermal tissues (which do not invaginate during gastrulation) tended to be higher than that in mesodermal tissues (which are derived from cells invaginating through the primitive streak). These results suggest that nascent mesoderm cells lacking the T gene are compromised in their ability to move away from the primitive streak. This indicates that one function of the T genemay be to regulate cell adhesion or cell motility properties in mesoderm cells. Wild-type cells in +/+ ↔ T/T chimeras appear to move normally to populate trunk and head mesoderm, suggesting that the reduced motility in T/T cells is a cell autonomous defect


2018 ◽  
Vol 20 (1) ◽  
pp. 19 ◽  
Author(s):  
Yadong Wei ◽  
Krishan Chhiba ◽  
Fengrui Zhang ◽  
Xujun Ye ◽  
Lihui Wang ◽  
...  

Sialic acid-binding Ig-like lectin 8 (Siglec-8) is expressed on the surface of human eosinophils, mast cells, and basophils—cells that participate in allergic and other diseases. Ligation of Siglec-8 by specific glycan ligands or antibodies triggers eosinophil death and inhibits mast cell degranulation; consequences that could be leveraged as treatment. However, Siglec-8 is not expressed in murine and most other species, thus limiting preclinical studies in vivo. Based on a ROSA26 knock-in vector, a construct was generated that contains the CAG promoter, a LoxP-floxed-Neo-STOP fragment, and full-length Siglec-8 cDNA. Through homologous recombination, this Siglec-8 construct was targeted into the mouse genome of C57BL/6 embryonic stem (ES) cells, and chimeric mice carrying the ROSA26-Siglec-8 gene were generated. After cross-breeding to mast cell-selective Cre-recombinase transgenic lines (CPA3-Cre, and Mcpt5-Cre), the expression of Siglec-8 in different cell types was determined by RT-PCR and flow cytometry. Peritoneal mast cells (dual FcεRI+ and c-Kit+) showed the strongest levels of surface Siglec-8 expression by multicolor flow cytometry compared to expression levels on tissue-derived mast cells. Siglec-8 was seen on a small percentage of peritoneal basophils, but not other leukocytes from CPA3-Siglec-8 mice. Siglec-8 mRNA and surface protein were also detected on bone marrow-derived mast cells. Transgenic expression of Siglec-8 in mice did not affect endogenous numbers of mast cells when quantified from multiple tissues. Thus, we generated two novel mouse strains, in which human Siglec-8 is selectively expressed on mast cells. These mice may enable the study of Siglec-8 biology in mast cells and its therapeutic targeting in vivo.


2002 ◽  
Vol 22 (10) ◽  
pp. 3509-3517 ◽  
Author(s):  
Hitoshi Okada ◽  
Woong-Kyung Suh ◽  
Jianping Jin ◽  
Minna Woo ◽  
Chunying Du ◽  
...  

ABSTRACT The mitochondrial proapoptotic protein Smac/DIABLO has recently been shown to potentiate apoptosis by counteracting the antiapoptotic function of the inhibitor of apoptosis proteins (IAPs). In response to apoptotic stimuli, Smac is released into the cytosol and promotes caspase activation by binding to IAPs, thereby blocking their function. These observations have suggested that Smac is a new regulator of apoptosis. To better understand the physiological function of Smac in normal cells, we generated Smac-deficient (Smac−/− ) mice by using homologous recombination in embryonic stem (ES) cells. Smac−/− mice were viable, grew, and matured normally and did not show any histological abnormalities. Although the cleavage in vitro of procaspase-3 was inhibited in lysates of Smac−/− cells, all types of cultured Smac−/− cells tested responded normally to all apoptotic stimuli applied. There were also no detectable differences in Fas-mediated apoptosis in the liver in vivo. Our data strongly suggest the existence of a redundant molecule or molecules capable of compensating for a loss of Smac function.


2000 ◽  
Vol 113 (1) ◽  
pp. 5-10 ◽  
Author(s):  
M.F. Pera ◽  
B. Reubinoff ◽  
A. Trounson

Embryonic stem (ES) cells are cells derived from the early embryo that can be propagated indefinitely in the primitive undifferentiated state while remaining pluripotent; they share these properties with embryonic germ (EG) cells. Candidate ES and EG cell lines from the human blastocyst and embryonic gonad can differentiate into multiple types of somatic cell. The phenotype of the blastocyst-derived cell lines is very similar to that of monkey ES cells and pluripotent human embryonal carcinoma cells, but differs from that of mouse ES cells or the human germ-cell-derived stem cells. Although our understanding of the control of growth and differentiation of human ES cells is quite limited, it is clear that the development of these cell lines will have a widespread impact on biomedical research.


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