scholarly journals Delayed DNA replication in haploid human embryonic stem cells

2021 ◽  
Author(s):  
Matthew M. Edwards ◽  
Michael V. Zuccaro ◽  
Ido Sagi ◽  
Qiliang Ding ◽  
Dan Vershkov ◽  
...  
Keyword(s):  
Stem Cells ◽  
Dna Replication ◽  
Embryonic Stem Cells ◽  
X Chromosome ◽  
Human Embryonic Stem Cells ◽  
Embryonic Stem ◽  
Replication Timing ◽  
Genetic System ◽  
X Chromosomes ◽  
Genomic Regions

Haploid human embryonic stem cells (ESCs) provide a powerful genetic system but diploidize at high rates. We hypothesized that diploidization results from aberrant DNA replication. To test this, we profiled DNA replication timing in isogenic haploid and diploid ESCs. The greatest difference was the earlier replication of the X Chromosome in haploids, consistent with the lack of X-Chromosome inactivation. We also identified 21 autosomal regions that had delayed replication in haploids, extending beyond the normal S phase and into G2/M. Haploid-delays comprised a unique set of quiescent genomic regions that are also underreplicated in polyploid placental cells. The same delays were observed in female ESCs with two active X Chromosomes, suggesting that increased X-Chromosome dosage may cause delayed autosomal replication. We propose that incomplete replication at the onset of mitosis could prevent cell division and result in re-entry into the cell cycle and whole genome duplication.

scholarly journals Delayed DNA replication in haploid human embryonic stem cells

2021 ◽  
Author(s):  
Matthew Micheal Edwards ◽  
Michael V. Zuccaro ◽  
Ido Sagi ◽  
Qiliang Ding ◽  
Dan Vershkov ◽  
...  
Keyword(s):  
Stem Cells ◽  
Dna Replication ◽  
Embryonic Stem Cells ◽  
X Chromosome ◽  
Human Embryonic Stem Cells ◽  
Embryonic Stem ◽  
Replication Timing ◽  
Genetic System ◽  
X Chromosomes ◽  
Genomic Regions

Haploid human embryonic stem cells (ESCs) provide a powerful genetic system but diploidize at high rates. We hypothesized that diploidization results from aberrant DNA replication. To test this, we profiled DNA replication timing in isogenic haploid and diploid ESCs. The greatest difference was the earlier replication of the X chromosome in haploids, consistent with the lack of X chromosome inactivation. Surprisingly, we also identified 21 autosomal regions that had dramatically delayed replication in haploids, extending beyond the normal S phase and into G2/M. Haploid-delays comprised a unique set of quiescent genomic regions that are also under-replicated in polyploid placental cells. The same delays were observed in female ESCs with two active X chromosomes, suggesting that increased X chromosome dosage may cause delayed autosomal replication. We propose that incomplete replication at the onset of mitosis could prevent cell division and result in re-entry into the cell cycle and whole genome duplication.

Aberrant Patterns of X Chromosome Inactivation in a New Line of Human Embryonic Stem Cells Established in Physiological Oxygen Concentrations

2014 ◽  
Vol 10 (4) ◽  
pp. 472-479 ◽  
Author(s):  
Juliana Andrea de Oliveira Georges ◽  
Naja Vergani ◽  
Simone Aparecida Siqueira Fonseca ◽  
Ana Maria Fraga ◽  
Joana Carvalho Moreira de Mello ◽  
...  
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
X Chromosome ◽  
Human Embryonic Stem Cells ◽  
Embryonic Stem ◽  
X Chromosome Inactivation ◽  
Chromosome Inactivation ◽  
Oxygen Concentrations

scholarly journals Histone H3 Lysine 36 Trimethylation Is Established over theXistPromoter by AntisenseTsixTranscription and Contributes to RepressingXistExpression

2015 ◽  
Vol 35 (22) ◽  
pp. 3909-3920 ◽  
Author(s):  
Tatsuya Ohhata ◽  
Mika Matsumoto ◽  
Martin Leeb ◽  
Shinwa Shibata ◽  
Satoshi Sakai ◽  
...  
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
X Chromosome ◽  
Antisense Rna ◽  
Histone H3 ◽  
Embryonic Stem ◽  
X Chromosome Inactivation ◽  
Chromosome Inactivation ◽  
X Chromosomes ◽  
Histone H3.3

One of the two X chromosomes in female mammals is inactivated by the noncodingXistRNA. In mice, X chromosome inactivation (XCI) is regulated by the antisense RNATsix, which repressesXiston the active X chromosome. In the absence ofTsix, PRC2-mediated histone H3 lysine 27 trimethylation (H3K27me3) is established over theXistpromoter. Simultaneous disruption ofTsixand PRC2 leads to derepression ofXistand in turn silencing of the single X chromosome in male embryonic stem cells. Here, we identified histone H3 lysine 36 trimethylation (H3K36me3) as a modification that is recruited byTsixcotranscriptionally and extends over theXistpromoter. Reduction of H3K36me3 by expression of a mutated histone H3.3 with a substitution of methionine for lysine at position 36 causes a significant derepression ofXist. Moreover, depletion of the H3K36 methylaseSetd2leads to upregulation ofXist, suggesting H3K36me3 as a modification that contributes to the mechanism ofTsixfunction in regulating XCI. Furthermore, we found that reduction of H3K36me3 does not facilitate an increase in H3K27me3 over theXistpromoter, indicating that additional mechanisms exist by whichTsixblocks PRC2 recruitment to theXistpromoter.

scholarly journals Human Embryonic Stem Cells Fail to Activate CHK1 and Commit to Apoptosis in Response to DNA Replication Stress

Stem Cells ◽  
2012 ◽  
Vol 30 (7) ◽  
pp. 1385-1393 ◽  
Author(s):  
Joëlle A. Desmarais ◽  
Michele J. Hoffmann ◽  
Gregg Bingham ◽  
Mary E. Gagou ◽  
Mark Meuth ◽  
...  
Keyword(s):  
Stem Cells ◽  
Dna Replication ◽  
Embryonic Stem Cells ◽  
Human Embryonic Stem Cells ◽  
Embryonic Stem ◽  
Replication Stress ◽  
Dna Replication Stress

scholarly journals A system for imaging the regulatory noncoding Xist RNA in living mouse embryonic stem cells

2011 ◽  
Vol 22 (14) ◽  
pp. 2634-2645 ◽  
Author(s):  
Karen Ng ◽  
Nathalie Daigle ◽  
Aurélien Bancaud ◽  
Tatsuya Ohhata ◽  
Peter Humphreys ◽  
...  
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
X Chromosome ◽  
Single Point ◽  
Embryonic Stem ◽  
Mouse Embryonic Stem Cells ◽  
Chromatin Domain ◽  
Dynamic Binding ◽  
X Chromosomes ◽  
Xist Rna

In mammals, silencing of one of the two X chromosomes in female cells compensates for the different number of X chromosomes between the sexes. The noncoding Xist RNA initiates X chromosome inactivation. Xist spreads from its transcription site over the X chromosome territory and triggers the formation of a repressive chromatin domain. To understand localization of Xist over one X chromosome we aimed to develop a system for investigating Xist in living cells. Here we report successful visualization of transgenically expressed MS2‑tagged Xist in mouse embryonic stem cells. Imaging of Xist during an entire cell cycle shows that Xist spreads from a single point to a steady state when the chromosome is covered with a constant amount of Xist. Photobleaching experiments of the established Xist cluster indicate that chromosome‑bound Xist is dynamic and turns over on the fully Xist covered chromosome. It appears that in interphase the loss of bound Xist and newly produced Xist are in equilibrium. We also show that the turnover of bound Xist requires transcription, and Xist binding becomes stable when transcription is inhibited. Our data reveal a strategy for visualizing Xist and indicate that spreading over the chromosome might involve dynamic binding and displacement.

scholarly journals A unique epigenetic signature is associated with active DNA replication loci in human embryonic stem cells

Epigenetics ◽  
2013 ◽  
Vol 9 (2) ◽  
pp. 257-267 ◽  
Author(s):  
Bing Li ◽  
Trent Su ◽  
Roberto Ferrari ◽  
Jing-Yu Li ◽  
Siavash K Kurdistani
Keyword(s):  
Stem Cells ◽  
Dna Replication ◽  
Embryonic Stem Cells ◽  
Human Embryonic Stem Cells ◽  
Embryonic Stem
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