scholarly journals Deletion of a pseudogene within a fragile site triggers the oncogenic expression of the mitotic CCSER1 gene

2021 ◽  
Vol 4 (8) ◽  
pp. e202101019
Author(s):  
Benedetta M Santoliquido ◽  
Michela Frenquelli ◽  
Claudia Contadini ◽  
Stefano Bestetti ◽  
Marco Gaviraghi ◽  
...  
Keyword(s):  
Kinase Inhibitors ◽  
Fragile Site ◽  
Aurora Kinase ◽  
Fragile Sites ◽  
Immune Recognition ◽  
Cis Acting ◽  
Replicative Stress ◽  
Acting Mechanism ◽  
Focal Ablation ◽  
Tcga Dataset

The oncogenic role of common fragile sites (CFS), focal and pervasive gaps in the cancer genome arising from replicative stress, remains controversial. Exploiting the TCGA dataset, we found that in most CFS the genes residing within the associated focal deletions are down-regulated, including proteins involved in tumour immune recognition. In a subset of CFS, however, the residing genes are surprisingly overexpressed. Within the most frequent CFS in this group, FRA4F, which is deleted in up to 18% of cancer cases and harbours the CCSER1 gene, we identified a region which includes an intronic, antisense pseudogene, TMSB4XP8. TMSB4XP8 focal ablation or transcriptional silencing elicits the overexpression of CCSER1, through a cis-acting mechanism. CCSER1 overexpression increases proliferation and triggers centrosome amplifications, multinuclearity, and aberrant mitoses. Accordingly, FRA4F is associated in patient samples to mitotic genes deregulation and genomic instability. As a result, cells overexpressing CCSER1 become sensitive to the treatment with aurora kinase inhibitors. Our findings point to a novel tumourigenic mechanism where focal deletions increase the expression of a new class of “dormant” oncogenes.

scholarly journals Werner syndrome helicase activity is essential in maintaining fragile site stability

2008 ◽  
Vol 180 (2) ◽  
pp. 305-314 ◽  
Author(s):  
Livia Maria Pirzio ◽  
Pietro Pichierri ◽  
Margherita Bignami ◽  
Annapaola Franchitto
Keyword(s):  
Werner Syndrome ◽  
Fragile Site ◽  
Chromosome Breakage ◽  
Fragile Sites ◽  
Helicase Activity ◽  
Dna Helicases ◽  
Replication Checkpoint ◽  
Replicative Stress ◽  
Fork Stalling ◽  
The Stability

WRN is a member of the RecQ family of DNA helicases implicated in the resolution of DNA structures leading to the stall of replication forks. Fragile sites have been proposed to be DNA regions particularly sensitive to replicative stress. Here, we establish that WRN is a key regulator of fragile site stability. We demonstrate that in response to mild doses of aphidicolin, WRN is efficiently relocalized in nuclear foci in replicating cells and that WRN deficiency is associated with accumulation of gaps and breaks at common fragile sites even under unperturbed conditions. By expressing WRN isoforms impaired in either helicase or exonuclease activity in defective cells, we identified WRN helicase activity as the function required for maintaining the stability of fragile sites. Finally, we find that WRN stabilizes fragile sites acting in a common pathway with the ataxia telangiectasia and Rad3 related replication checkpoint. These findings provide the first evidence of a crucial role for a helicase in protecting cells against chromosome breakage at normally occurring replication fork stalling sites.

Aurora Kinase Inhibitors in Head and Neck Cancer

2018 ◽  
Vol 18 (3) ◽  
pp. 199-213
Author(s):  
Guangying Qi ◽  
Jing Liu ◽  
Sisi Mi ◽  
Takaaki Tsunematsu ◽  
Shengjian Jin ◽  
...  
Keyword(s):  
Head And Neck Cancer ◽  
Cancer Therapy ◽  
Kinase Inhibitors ◽  
Biological Function ◽  
Aurora Kinase ◽  
Aurora Kinases ◽  
Related Research ◽  
Chemotherapy Drugs ◽  
Aurora Kinase Inhibitors

Aurora kinases are a group of serine/threonine kinases responsible for the regulation of mitosis. In recent years, with the increase in Aurora kinase-related research, the important role of Aurora kinases in tumorigenesis has been gradually recognized. Aurora kinases have been regarded as a new target for cancer therapy, resulting in the development of Aurora kinase inhibitors. The study and application of these small-molecule inhibitors, especially in combination with chemotherapy drugs, represent a new direction in cancer treatment. This paper reviews studies on Aurora kinases from recent years, including studies of their biological function, their relationship with tumor progression, and their inhibitors.

scholarly journals Activator-independent gene expression in Neurospora crassa

Genetics ◽  
1996 ◽  
Vol 142 (2) ◽  
pp. 417-423
Author(s):  
Wayne K Versaw ◽  
Robert L Metzenberg
Keyword(s):  
Gene Expression ◽  
Neurospora Crassa ◽  
Chromosomal Rearrangement ◽  
Position Effect ◽  
Upstream Region ◽  
Phosphorus Metabolism ◽  
Position Effects ◽  
Cis Acting ◽  
Independent Gene ◽  
Acting Mechanism

Abstract A transgenic position effect that causes activator-independent gene expression has been described previously for three Neurospora crassa phosphate-repressible genes. We report analogous findings for two additional positively regulated genes, qa-2  + and ars-1  +, indicating that such position effects are not limited to genes involved in phosphorus metabolism. In addition, we have characterized a number of mutants that display activator-independent gene expression. Each of these mutants contains a chromosomal rearrangement with one breakpoint located in the 5’-upstream region of the affected gene. This suggests that the rearrangements are associated with activator-independent gene expression and that these cis-acting mutations may represent a position effect similar to that responsible for rendering some transgenes independent of their transcriptional activators. We suggest that positively regulated genes in N.  crassa are normally held in a transcriptionally repressed state by a cis-acting mechanism until specifically activated. Disruption of this cis-acting mechanism, either by random integration of a gene by transformation or by chromosomal rearrangement, renders these genes independent or partly independent of the transcriptional activator on which they normally depend.

Discovery of novel 2,4-disubstituted pyrimidines as Aurora kinase inhibitors

2020 ◽  
Vol 30 (3) ◽  
pp. 126885 ◽  
Author(s):  
Yu Xu ◽  
Shu-Yi Hao ◽  
Xiu-Juan Zhang ◽  
Wen-Bo Li ◽  
Xue-Peng Qiao ◽  
...  
Keyword(s):  
Kinase Inhibitors ◽  
Aurora Kinase ◽  
Aurora Kinase Inhibitors

Fragile Sites on Chromosomes

PEDIATRICS ◽  
1982 ◽  
Vol 69 (1) ◽  
pp. 121-123
Author(s):  
Frederick Hecht ◽  
Thomas W. Glover ◽  
Barbara Kaiser-Hecht
Keyword(s):  
Mental Retardation ◽  
X Chromosome ◽  
Fanconi Anemia ◽  
Ataxia Telangiectasia ◽  
Autosomal Recessive ◽  
Fragile Site ◽  
Chromosome Instability ◽  
Chromosome Complement ◽  
Fragile Sites ◽  
Chromosome Fragility

A fragile site on the X chromosome is associated with a common form of mental retardation in males and a proportion of females.1-3 This association was not fully appreciated when the fragile site on the X was first described in 1969,4 but it is crystal-clear today. Chromosome fragility can be random, as in Fanconi anemia, Bloom syndrome, and ataxia-telangiectasia, the chromosome instability syndromes.5 Breaks and rearrangements of chromosomes are seen in these disorders, all of which are autosomal recessive conditions predisposing to cancer. Fragile sites are special spots in the genome where gaps and breaks occur nonrandomly. The balance of the chromosome complement is normal.

Generation of a new adenovirus type 12-inducible fragile site by insertion of an artificial U2 locus in the human genome

1993 ◽  
Vol 13 (10) ◽  
pp. 6064-6070
Author(s):  
Y P Li ◽  
R Tomanin ◽  
J R Smiley ◽  
S Bacchetti
Keyword(s):  
Human Genome ◽  
Gene Cluster ◽  
Fragile Site ◽  
Adenovirus Type ◽  
Fragile Sites ◽  
Human Cells ◽  
Major Site ◽  
Chromosome 13 ◽  
Direct Assessment

Infection with adenovirus type 12 (Ad12) induces four fragile sites in the human genome (H.F. Stich, G.L. van Hoosier, and J.J. Trentin, Exp. Cell Res. 34:400-403, 1964; H. zur Hausen, J. Virol. 1:1174-1185, 1967). The major site, at 17q21-22, contains the U2 gene cluster, which is specifically disrupted by infection in at least a percentage of the cells (D.M. Durnam, J.C. Menninger, S.H. Chandler, P.P. Smith, and J.K. McDougall, Mol. Cell. Biol. 8:1863-1867, 1988). For direct assessment of whether the U2 locus is the target of the Ad12 effect, an artificial locus, constructed in vitro and consisting of tandem arrays of the U2 6-kbp monomer, was transfected into human cells. We report that integration of this artificial locus on the p arm of chromosome 13 creates a new Ad12-inducible fragile site.

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