scholarly journals 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

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.

1993 ◽  
Vol 13 (10) ◽  
pp. 6064-6070
Author(s):  
Y P Li ◽  
R Tomanin ◽  
J R Smiley ◽  
S Bacchetti

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.


1995 ◽  
Vol 15 (11) ◽  
pp. 6256-6261 ◽  
Author(s):  
S Gargano ◽  
P Wang ◽  
E Rusanganwa ◽  
S Bacchetti

Adenovirus type 12 induces four fragile sites upon infection of human cells. The U2 locus, consisting of up to 20 tandem repeats of a 5.8-kbp monomer, maps at the most sensitive of these sites at 17q21-22. We have previously shown that an artificial U2 locus integrated into the human genome generates a new virus-induced fragile site. To determine which elements within the U2 monomer are responsible for fragility, we constructed loci consisting of tandem repeats of subfragments of the U2 monomer. With this approach, we demonstrate that a transcriptionally competent U2 gene is necessary and sufficient for virus-induced fragility and that no other element within the 5.8-kbp monomer contributes to this effect.


1988 ◽  
Vol 8 (5) ◽  
pp. 1863-1867
Author(s):  
D M Durnam ◽  
J C Menninger ◽  
S H Chandler ◽  
P P Smith ◽  
J K McDougall

Using in situ hybridization, we found that the U2 small nuclear RNA gene cluster mapped very close to and was frequently disrupted by the gaps and breaks induced specifically in the human 17q21-q22 region by highly oncogenic adenovirus type 12 (Ad12). Restriction mapping revealed no structural alterations in the U2 gene locus as a result of Ad12 infection. Likewise, no Ad12-induced alterations in U2 RNA levels were detected. We estimate that the maximum size of the region specifically disrupted by this virus was less than 350 to 700 kilobases. A comparison of these data with similar data regarding biochemically induced fragile sites was made.


1988 ◽  
Vol 8 (5) ◽  
pp. 1863-1867 ◽  
Author(s):  
D M Durnam ◽  
J C Menninger ◽  
S H Chandler ◽  
P P Smith ◽  
J K McDougall

Using in situ hybridization, we found that the U2 small nuclear RNA gene cluster mapped very close to and was frequently disrupted by the gaps and breaks induced specifically in the human 17q21-q22 region by highly oncogenic adenovirus type 12 (Ad12). Restriction mapping revealed no structural alterations in the U2 gene locus as a result of Ad12 infection. Likewise, no Ad12-induced alterations in U2 RNA levels were detected. We estimate that the maximum size of the region specifically disrupted by this virus was less than 350 to 700 kilobases. A comparison of these data with similar data regarding biochemically induced fragile sites was made.


2019 ◽  
Vol 47 (18) ◽  
pp. 9685-9695 ◽  
Author(s):  
Michal Irony-Tur Sinai ◽  
Anita Salamon ◽  
Noemie Stanleigh ◽  
Tchelet Goldberg ◽  
Aryeh Weiss ◽  
...  

Abstract Common fragile sites (CFSs) are genomic regions prone to breakage under replication stress conditions recurrently rearranged in cancer. Many CFSs are enriched with AT-dinucleotide rich sequences (AT-DRSs) which have the potential to form stable secondary structures upon unwinding the double helix during DNA replication. These stable structures can potentially perturb DNA replication progression, leading to genomic instability. Using site-specific targeting system, we show that targeted integration of a 3.4 kb AT-DRS derived from the human CFS FRA16C into a chromosomally stable region within the human genome is able to drive fragile site formation under conditions of replication stress. Analysis of >1300 X chromosomes integrated with the 3.4 kb AT-DRS revealed recurrent gaps and breaks at the integration site. DNA sequences derived from the integrated AT-DRS showed in vitro a significantly increased tendency to fold into branched secondary structures, supporting the predicted mechanism of instability. Our findings clearly indicate that intrinsic DNA features, such as complexed repeated sequence motifs, predispose the human genome to chromosomal instability.


2015 ◽  
Vol 2015 ◽  
pp. 1-15
Author(s):  
Shelly Sehgal ◽  
Sanjana Kaul ◽  
M. K. Dhar

The present investigation was aimed at understanding the molecular mechanism of gene amplification. Interplay of fragile sites in promoting gene amplification was also elucidated. The amplification promoting sequences were chosen from theSaccharomyces cerevisiaeARS, 5S rRNA regions ofPlantago ovataandP. lagopus, proposed sites of replication pausing atSte20gene locus ofS. cerevisiae,and the bend DNA sequences within fragile site FRA11A in humans. The gene amplification assays showed that plasmid bearing APS from yeast and human beings led to enhanced protein concentration as compared to the wild type. Both thein silicoandin vitroanalyses were pointed out at the strong bending potential of these APS. In addition, high mitotic stability and presence of TTTT repeats and SAR amongst these sequences encourage gene amplification. Phylogenetic analysis ofS. cerevisiaeARS was also conducted. The combinatorial power of different aspects of APS analyzed in the present investigation was harnessed to reach a consensus about the factors which stimulate gene expression, in presence of these sequences. It was concluded that the mechanism of gene amplification was that AT rich tracts present in fragile sites of yeast serve as binding sites for MAR/SAR and DNA unwinding elements. The DNA protein interactions necessary for ORC activation are facilitated by DNA bending. These specific bindings at ORC promote repeated rounds of DNA replication leading to gene amplification.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Philippe Fernandes ◽  
Benoit Miotto ◽  
Claude Saint-Ruf ◽  
Maha Said ◽  
Viviana Barra ◽  
...  

AbstractCommon fragile sites (CFSs) are genomic regions frequently involved in cancer-associated rearrangements. Most CFSs lie within large genes, and their instability involves transcription- and replication-dependent mechanisms. Here, we uncover a role for the mitochondrial stress response pathway in the regulation of CFS stability in human cells. We show that FANCD2, a master regulator of CFS stability, dampens the activation of the mitochondrial stress response and prevents mitochondrial dysfunction. Genetic or pharmacological activation of mitochondrial stress signaling induces CFS gene expression and concomitant relocalization to CFSs of FANCD2. FANCD2 attenuates CFS gene transcription and promotes CFS gene stability. Mechanistically, we demonstrate that the mitochondrial stress-dependent induction of CFS genes is mediated by ubiquitin-like protein 5 (UBL5), and that a UBL5-FANCD2 dependent axis regulates the mitochondrial UPR in human cells. We propose that FANCD2 coordinates nuclear and mitochondrial activities to prevent genome instability.


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