DNA hypomethylation and unusual chromosome instability in cell lines fromICF syndrome patients

2000 ◽  
Vol 89 (1-2) ◽  
pp. 121-128 ◽  
Author(s):  
C.M. Tuck-Muller ◽  
A. Narayan ◽  
F. Tsien ◽  
D.F.C.M. Smeets ◽  
J. Sawyer ◽  
...  
Keyword(s):  
Cell Lines ◽  
Chromosome Instability ◽  
Dna Hypomethylation ◽  
Unusual Chromosome

DNA methylation patterns associated with asparagine synthetase expression in asparagine-overproducing and -auxotrophic cells

1989 ◽  
Vol 9 (7) ◽  
pp. 2922-2927
Author(s):  
I L Andrulis ◽  
M T Barrett
Keyword(s):  
Cell Lines ◽  
Chinese Hamster Ovary Cells ◽  
Methylation Status ◽  
Chinese Hamster ◽  
Resistant Cell ◽  
Methylation Pattern ◽  
Asparagine Synthetase ◽  
Synthetase Activity ◽  
Dna Hypomethylation ◽  
Ovary Cells

In Chinese hamster ovary cells, the gene for asparagine synthetase, which spans 20 kilobase pairs, was found to contain a cluster of potential sites for CpG methylation in a 1-kilobase-pair region surrounding the first exon. Fourteen of the sites that could be assayed for methylation by MspI-HpaII digestions were found in this region, with an additional nine MspI sites spread throughout the remainder of the gene. The methylation status of the gene was analyzed in a series of cell lines that differed in the amount of asparagine synthetase activity. The level of expression showed a direct correlation with the extent of methylation of a subset of the MspI sites found in the 5' region of the gene. The rest of the gene was completely methylated in most cell lines. Wild-type cells, which expressed a basal level of asparagine synthetase activity, were partially demethylated in the 5' region. In contrast, asparagine-requiring N3 cells, which lacked detectable mRNA for asparagine synthetase, were methylated throughout the entire gene. Spontaneous revertants of strain N3, selected for growth in asparagine-free medium, exhibited extensive hypomethylation of the asparagine synthetase gene. The methylation pattern of the gene in cell lines that overproduced the enzyme was also examined. Albizziin-resistant cell lines, which had amplified copies of the gene, were extensively demethylated in the 5' region. Overexpression of asparagine synthetase in beta-aspartyl hydroxamate-resistant lines without amplified copies of the gene was also correlated with DNA hypomethylation.

scholarly journals The temporal dynamics of chromosome instability in ovarian cancer cell lines and primary patient samples

PLoS Genetics ◽  
2017 ◽  
Vol 13 (4) ◽  
pp. e1006707 ◽  
Author(s):  
Signe Penner-Goeke ◽  
Zelda Lichtensztejn ◽  
Megan Neufeld ◽  
Jennifer L. Ali ◽  
Alon D. Altman ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Cell Lines ◽  
Cancer Cell ◽  
Temporal Dynamics ◽  
Ovarian Cancer Cell ◽  
Chromosome Instability ◽  
Cancer Cell Lines ◽  
Ovarian Cancer Cell Lines

scholarly journals BUB1 mediation of caspase-independent mitotic death determines cell fate

2007 ◽  
Vol 178 (2) ◽  
pp. 283-296 ◽  
Author(s):  
Yohei Niikura ◽  
Amruta Dixit ◽  
Ray Scott ◽  
Guy Perkins ◽  
Katsumi Kitagawa
Keyword(s):  
Cell Death ◽  
Cell Fate ◽  
Cell Lines ◽  
Chromosome Instability ◽  
Spindle Checkpoint ◽  
Mitotic Cell ◽  
Endonuclease G ◽  
Colon Tumors ◽  
Mitotic Death ◽  
Apoptosis Inducing Factor

The spindle checkpoint that monitors kinetochore–microtubule attachment has been implicated in tumorigenesis; however, the relation between the spindle checkpoint and cell death remains obscure. In BUB1-deficient (but not MAD2-deficient) cells, conditions that activate the spindle checkpoint (i.e., cold shock or treatment with nocodazole, paclitaxel, or 17-AAG) induced DNA fragmentation during early mitosis. This mitotic cell death was independent of caspase activation; therefore, we named it caspase-independent mitotic death (CIMD). CIMD depends on p73, a homologue of p53, but not on p53. CIMD also depends on apoptosis-inducing factor and endonuclease G, which are effectors of caspase-independent cell death. Treatment with nocodazole, paclitaxel, or 17-AAG induced CIMD in cell lines derived from colon tumors with chromosome instability, but not in cells from colon tumors with microsatellite instability. This result was due to low BUB1 expression in the former cell lines. When BUB1 is completely depleted, aneuploidy rather than CIMD occurs. These results suggest that cells prone to substantial chromosome missegregation might be eliminated via CIMD.

Hypomethylation of classical satellite DNA and chromosome instability in lymphoblastoid cell lines

1993 ◽  
Vol 91 (6) ◽  
Author(s):  
Anna Almeida ◽  
Nadja Kokalj-Vokac ◽  
Danielle Lefrancois ◽  
Evani Viegas-Pequignot ◽  
Marc Jeanpierre ◽  
...  
Keyword(s):  
Cell Lines ◽  
Satellite Dna ◽  
Chromosome Instability ◽  
Lymphoblastoid Cell Lines

Methylation Profile of B-Chronic Lymphocytic Leukemia Cells.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2951-2951
Author(s):  
Jun Fan ◽  
Asou Norio ◽  
Masao Matsuoka
Keyword(s):  
Dna Methylation ◽  
Chronic Lymphocytic Leukemia ◽  
Cell Lines ◽  
Mammalian Cells ◽  
Mononuclear Cells ◽  
Cpg Island ◽  
Methylation Status ◽  
Lymphocytic Leukemia ◽  
Dna Hypomethylation ◽  
Peripheral Blood Mononuclear

Abstract DNA methylation plays an important role in the development and aging of mammalian cells, and its dysregulation has been frequently observed in cancer cells. The purpose of this study is to investigate the involvement of aberrant DNA methylation in B chronic lymphocytic leukemia (B-CLL) cells. We compared methylation status of B-CLL cells isolated from patients with that of normal CD19+ cells isolated from health donors by methylated CpG island amplification/representative difference analysis method. 5 hypermethylated and 27 hypomethylated DNA regions were identified in B-CLL sample. Among the 27 hypomethylated regions, 5 located on chromosome 9q34, 3 on 10q25-26 and 4 on 19q13. Methylation status was confirmed by sequencing using sodium bisulfite-treated DNA samples. By comparing DNA samples from same patients at different clinical stages, we found that lower methylation density in these regions is linked with disease progression. Expression of 15 genes surrounding hypomethylated regions was studied by RT-PCR. Expression of laminin beta3 gene and melanotransferrin gene was found to be upregulated in all B-CLL cell lines as well as lymphoma cell lines comparing with normal CD19+ peripheral blood mononuclear cells. B-cell CLL/lymphoma 11b gene showed increased expression in only 2 B-CLL cell lines. For other genes, no transcriptional change was found regardless of changed DNA methylation. This study showed the predominance of DNA hypomethylation in B-CLL cells compared with hypermethylation. Hypomethylated regions clustered in a limited number of chromosomes and methylation density appeared to be inversely correlated with disease progress. Figure Figure

scholarly journals Deregulation of cyclin E in human cells interferes with prereplication complex assembly

2004 ◽  
Vol 165 (6) ◽  
pp. 789-800 ◽  
Author(s):  
Susanna Ekholm-Reed ◽  
Juan Méndez ◽  
Donato Tedesco ◽  
Anders Zetterberg ◽  
Bruce Stillman ◽  
...  
Keyword(s):  
Dna Replication ◽  
Cell Lines ◽  
Broad Spectrum ◽  
Cyclin E ◽  
Chromosome Instability ◽  
S Phase ◽  
Potential Mechanism ◽  
Minichromosome Maintenance ◽  
Origins Of Replication ◽  
Initiation Of Replication

Deregulation of cyclin E expression has been associated with a broad spectrum of human malignancies. Analysis of DNA replication in cells constitutively expressing cyclin E at levels similar to those observed in a subset of tumor-derived cell lines indicates that initiation of replication and possibly fork movement are severely impaired. Such cells show a specific defect in loading of initiator proteins Mcm4, Mcm7, and to a lesser degree, Mcm2 onto chromatin during telophase and early G1 when Mcm2–7 are normally recruited to license origins of replication. Because minichromosome maintenance complex proteins are thought to function as a heterohexamer, loading of Mcm2-, Mcm4-, and Mcm7-depleted complexes is likely to underlie the S phase defects observed in cyclin E–deregulated cells, consistent with a role for minichromosome maintenance complex proteins in initiation of replication and fork movement. Cyclin E–mediated impairment of DNA replication provides a potential mechanism for chromosome instability observed as a consequence of cyclin E deregulation.

scholarly journals Site-specific methylation of the CMV promoter alters transcriptional factor-transgene interactions and demethylation leads to enhanced specific productivity of a recombinant monoclonal antibody in CHO cultures

2021 ◽  
Author(s):  
Hussain Dahodwala ◽  
Sophia Amenya ◽  
Sarah Nicoletti ◽  
Matthew Henry ◽  
Diane Lees-Murdock ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Transcription Factor ◽  
Cell Line ◽  
Cell Lines ◽  
Specific Productivity ◽  
Dna Hypomethylation ◽  
Cmv Promoter ◽  
Site Specific ◽  
Factor Binding ◽  
Lower Productivity

Chinese hamster ovary (CHO) cells are the industry standard cell line for high yield expression of biopharmaceuticals. However, leveraging the influencers of specific productivity to expedite generation of high productivity clones remains a challenge. One factor impacting specific productivity is the strong, constitutive activity of the CMV promoter used in most vectors for transgene applications. In this study, we sought to understand the influence of DNA methylation along the CMV promoter in driving transcription in higher vs lower productivity cell lines. Bisulfite pyrosequencing was used to characterize the CMV methylation pattern in parental (lower productivity) and DHFR-amplified (higher productivity) monoclonal antibody-expressing cell lines. In-silico analysis of promoter sequence revealed a large CpG island covering the transcription factor binding sites for CREB1 and NFκB. Variable methylation of specific CpG sites appears correlated with transcription factor binding. Treatment of the cells with 5’-azacytidine, a known DNA hypomethylation agent, led to methylation reduction in the CMV promoter, particularly upstream of the NFκB binding consensus region. This induced DNA hypomethylation correlated with cell line-specific increases in RNA expression and specific productivity. These encouraging findings suggest that site-specific methylation along the CMV promoter plays an underutilized, and important role in improving transgene transcription using the CMV promoter and de-bottlenecking the production capacity of CHO cell lines.

X-chromosome instability in pluripotential stem cell lines derived from parthenogenetic embryos

Development ◽  
1983 ◽  
Vol 74 (1) ◽  
pp. 297-309
Author(s):  
E. J. Robertson ◽  
M. J. Evans ◽  
M. H. Kaufman
Keyword(s):  
Stem Cell ◽  
Cell Lines ◽  
X Chromosome ◽  
Early Stage ◽  
Chromosome Instability ◽  
Chromosome Complement ◽  
Selective Advantage ◽  
Deletion Event ◽  
Stem Cell Lines ◽  
Parthenogenetic Embryos

The karyotype of six pluripotential stem cell lines derived from haploid and two additional lines derived from diploid parthenogenetic embryos is described. All these lines are diploid and possess a normal autosomal complement. The stage at which diploidization of the haploid cells occurs is not yet known. The XX-chromosome complement in these lines is unstable, although in two haploid-derived lines and one diploid-derived line many normal XX-bearing cells are found in early cultures. All of the lines so far examined either become XO (rarely), or a single X chromosome shows a deletion in the distal region. The extent of this deletion varies between lines, but the position of the breakpoint appears to be constant for a given line. We suggest that these cytogenetic findings raise the possibility that a single deletion event occurring at an early stage during the isolation of these lines may confer a selective advantage to those cells carrying the deleted X chromosome.

Sign in / Sign up

Export Citation Format

Share Document