The susceptibility of Werner’s syndrome and other human skin fibroblasts to SV40-induced transformation and immortalization

Huschtscha, Lily I.; Thompson, Karen; Holliday, Robin

doi:10.1098/rspb.1986.0070

Cited by 21 publications

(5 citation statements)

References 16 publications

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“…Because there is evidence that the mammalian WRN and BLM RecQ helicases participate in telomere maintenance (31)(32)(33)(34)(35), including standard ALT (36), it is possible that the absence of WRN in AG11395 contributed to the development of its type I-like telomeres. However, if WRN does participate in the standard ALT mechanism, there is no absolute requirement for WRN because the only other immortalized cell line lacking WRN, WV (19), has a standard ALT phenotype (Fig. 5D).…”

Section: Discussionmentioning

confidence: 99%

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A Novel Telomere Structure in a Human Alternative Lengthening of Telomeres Cell Line

et al. 2005

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Cancer cells require mechanisms to maintain telomeres. Most use telomerase, but 5% to 20% of tumors use alternative lengthening of telomeres (ALT), a telomerase-independent mechanism that seems to depend on recombination. ALT is characterized by amplification of telomere TTAGGG repeats to lengths beyond 50 kb, by elevated rates of telomere recombination, and by nuclear structures called ALT-associated promyelocytic leukemia bodies. In Saccharomyces cerevisiae, survivors of telomerase inactivation also use recombination to maintain telomeres. There are two types of survivors, which differ in telomere structure. The first possesses telomere repeats and the YVsubtelomeric element amplified together as a tandem array at chromosome termini (type I), and the other possesses amplification of telomeric repeats alone (type II), similar to previously described human ALT cells. Here, we describe the first human ALT cell line having ''tandem array'' telomeres with a structure similar to that of type I yeast survivors. The chromosome termini consist of a repeat unit containing f f2.5 kb of SV40 DNA and a variable amount of TTAGGG sequence repeated in tandem an average of 10 to 20 times. Similar to previously described ALT cells, they show evidence of telomere recombination, but unlike standard ALT cells, they lack ALT-associated promyelocytic leukemia bodies and their telomeres are transcribed. These findings have implications for the pathogenesis and diagnosis of cancer.

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Section: Discussionmentioning

confidence: 99%

“…WV (SV40-transformed Werner mutant fibroblast; ref. 19) was kindly provided by Prof. Sydney Shall (Cell and Molecular Biology Laboratory, University of Sussex, Sussex, United Kingdom). Cells were grown in 5% CO 2 under conditions recommended by the supplier.…”

Section: Methodsmentioning

confidence: 99%

A Novel Telomere Structure in a Human Alternative Lengthening of Telomeres Cell Line

et al. 2005

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“…The stalled growth and prominent senescence produced by acute knockdown of WRN in primary fibroblasts contrasts with the growth features of cells derived from Werner patients. Primary cells from Werner patients, although growing poorly, have been passaged in culture and can be immortalized with SV40 virus, Epstein-Barr virus, or telomerase (10,27). Werner patients also develop normally through childhood.…”

Section: Discussionmentioning

confidence: 99%

Werner Protein Protects Nonproliferating Cells from Oxidative DNA Damage

Székely

Bleichert²,

Nümann³

et al. 2005

Molecular and Cellular Biology

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Werner syndrome, caused by mutations of the WRN gene, mimics many changes of normal aging. Although roles for WRN protein in DNA replication, recombination, and telomere maintenance have been suggested, the pathology of rapidly dividing cells is not a feature of Werner syndrome. To identify cellular events that are specifically vulnerable to WRN deficiency, we used RNA interference (RNAi) to knockdown WRN or BLM (the RecQ helicase mutated in Bloom syndrome) expression in primary human fibroblasts. Withdrawal of WRN or BLM produced accelerated cellular senescence phenotype and DNA damage response in normal fibroblasts, as evidenced by induction of ␥H2AX and 53BP1 nuclear foci. After WRN depletion, the induction of these foci was seen most prominently in nondividing cells. Growth in physiological (3%) oxygen or in the presence of an antioxidant prevented the development of the DNA damage foci in WRN-depleted cells, whereas acute oxidative stress led to inefficient repair of the lesions. Furthermore, WRN RNAi-induced DNA damage was suppressed by overexpression of the telomere-binding protein TRF2. These conditions, however, did not prevent the DNA damage response in BLM-ablated cells, suggesting a distinct role for WRN in DNA homeostasis in vivo. Thus, manifestations of Werner syndrome may reflect an impaired ability of slowly dividing cells to limit oxidative DNA damage.Among the simple Mendelian disorders of humans, Werner syndrome most closely resembles an acceleration of normal aging (20,32). Although the distribution of lesions is somewhat atypical for normal aging, Werner patients show osteoporosis, atherosclerosis, thinning of skin, graying of hair, cataracts and diabetes (33). Peripheral insulin resistance appears to precede the diabetes, as it does in maturity onset type II diabetes in the general population. Werner syndrome has attracted the interest of a number of investigators because of the hope that understanding its pathogenesis could shed light on the molecular weak links in normal aging.The gene mutated in Werner syndrome encodes the WRN protein, a 3Ј-5Ј DNA helicase of the RecQ family that also exhibits exonuclease activity (for a review, see references 25, 35, and 37). WRN has been suggested to function in DNA replication and repair. The helicase is capable of unwinding various DNA structures such as D-loops and G-quartets, and various structures potentially associated with progressing replication forks, as well as promoting migration of Holliday junctions such as might be formed as intermediates in DNA recombination. WRN can directly interact with a variety of proteins involved in these processes, including the major DNA polymerase, polymerase delta; polymerase beta, a DNA polymerase used in base excision repair; the Ku complex; the FEN1 nuclease that removes single-stranded branch structures in DNA; and the p53 DNA checkpoint gene. Previous studies reported slow progression of S phase in cells from Werner patients and proposed that fewer origins of replication are used and/or that the replicati...

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“…WV1 and AG11395 contain WRN mutations and lack detectable WRN protein (Huschtscha et al 1986;Saito and Moses 1991;Prince et al 1999;J. Oshima, pers.…”

Section: Cell Lines and Culturementioning

confidence: 99%

Loss of Werner syndrome protein function promotes aberrant mitotic recombination

Prince¹,

Emond²,

Monnat³

2001

Genes Dev.

147

124

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The chromosome 8p11-12 Werner syndrome (WRN ) locus encodes a RecQ helicase protein of unknown function that possesses both 3 → 5 helicase and 3 → 5 exonuclease activities. We show that WRN cell lines display a marked reduction in cell proliferation following mitotic recombination, and generate few viable gene conversion-type recombinants. These findings indicate that WRN plays a role in mitotic recombination, and that a loss of WRN function may promote genetic instability and disease via recombination-initiated mitotic arrest, cell death, or gene rearrangement.

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The susceptibility of Werner’s syndrome and other human skin fibroblasts to SV40-induced transformation and immortalization

Cited by 21 publications

References 16 publications

A Novel Telomere Structure in a Human Alternative Lengthening of Telomeres Cell Line

A Novel Telomere Structure in a Human Alternative Lengthening of Telomeres Cell Line

Werner Protein Protects Nonproliferating Cells from Oxidative DNA Damage

Loss of Werner syndrome protein function promotes aberrant mitotic recombination

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