Comparative studies of host-cell reactivation, colony forming ability and excision repair after UV irradiation of xeroderma pigmentosum, normal human and some other mammalian cells

We have measured the removal of UV-induced pyrimidine dimers from DNA fragments of the adenosine deaminase (ADA) and dihydrofolate reductase (DHFR) genes in primary normal human and xeroderma pigmentosum complementation group C (XP-C) cells. Using strand-specific probes, we show that in normal cells, preferential repair of the 5' part of the ADA gene is due to the rapid and efficient repair of the transcribed strand. Within 8 h after irradiation with UV at 10 J m-2, 70% of the pyrimidine dimers in this strand are removed. The nontranscribed strand is repaired at a much slower rate, with 30% dimers removed after 8 h. Repair of the transcribed strand in XP-C cells occurs at a rate indistinguishable from that in normal cells, but the nontranscribed strand is not repaired significantly in these cells. Similar results were obtained for the DHFR gene. In the 3' part of the ADA gene, however, both normal and XP-C cells perform fast and efficient repair of either strand, which is likely to be caused by the presence of transcription units on both strands. The factor defective in XP-C cells is apparently involved in the processing of DNA damage in inactive parts of the genome, including nontranscribed strands of active genes. These findings have important implications for the understanding of the mechanism of UV-induced excision repair and mutagenesis in mammalian cells.

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Repair of sulfur mustard-induced DNA damage in mammalian cells measured by a host cell reactivation assay

Carcinogenesis ◽

10.1093/carcin/22.4.661 ◽

2001 ◽

Vol 22 (4) ◽

pp. 661-664 ◽

Cited By ~ 25

Author(s):

Z. Matijasevic ◽

M.L. Precopio ◽

J.E. Snyder ◽

D.B. Ludlum

Keyword(s):

Dna Damage ◽

Host Cell ◽

Mammalian Cells ◽

Sulfur Mustard ◽

Cell Reactivation ◽

Host Cell Reactivation

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Xeroderma pigmentosum complementation group C cells remove pyrimidine dimers selectively from the transcribed strand of active genes.

Molecular and Cellular Biology ◽

10.1128/mcb.11.8.4128 ◽

1991 ◽

Vol 11 (8) ◽

pp. 4128-4134 ◽

Cited By ~ 222

Author(s):

J Venema ◽

A van Hoffen ◽

V Karcagi ◽

A T Natarajan ◽

A A van Zeeland ◽

...

Keyword(s):

Xeroderma Pigmentosum ◽

Mammalian Cells ◽

Excision Repair ◽

Complementation Group ◽

C Cells ◽

Dhfr Gene ◽

Normal Cells ◽

Pyrimidine Dimers ◽

Normal Human ◽

Active Genes

We have measured the removal of UV-induced pyrimidine dimers from DNA fragments of the adenosine deaminase (ADA) and dihydrofolate reductase (DHFR) genes in primary normal human and xeroderma pigmentosum complementation group C (XP-C) cells. Using strand-specific probes, we show that in normal cells, preferential repair of the 5' part of the ADA gene is due to the rapid and efficient repair of the transcribed strand. Within 8 h after irradiation with UV at 10 J m-2, 70% of the pyrimidine dimers in this strand are removed. The nontranscribed strand is repaired at a much slower rate, with 30% dimers removed after 8 h. Repair of the transcribed strand in XP-C cells occurs at a rate indistinguishable from that in normal cells, but the nontranscribed strand is not repaired significantly in these cells. Similar results were obtained for the DHFR gene. In the 3' part of the ADA gene, however, both normal and XP-C cells perform fast and efficient repair of either strand, which is likely to be caused by the presence of transcription units on both strands. The factor defective in XP-C cells is apparently involved in the processing of DNA damage in inactive parts of the genome, including nontranscribed strands of active genes. These findings have important implications for the understanding of the mechanism of UV-induced excision repair and mutagenesis in mammalian cells.

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Host-cell Reactivation in Mammalian Cells

International Journal of Radiation Biology ◽

10.1080/716100001 ◽

1972 ◽

Vol 22 (2) ◽

pp. 167-174 ◽

Cited By ~ 13

Author(s):

C. David Lytle

Keyword(s):

Host Cell ◽

Mammalian Cells ◽

Cell Reactivation ◽

Host Cell Reactivation

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Defining the function of xeroderma pigmentosum group F protein in psoralen interstrand cross-link-mediated DNA repair and mutagenesis

Biochemical Journal ◽

10.1042/bj20031143 ◽

2004 ◽

Vol 379 (1) ◽

pp. 71-78 ◽

Cited By ~ 9

Author(s):

Zhiwen CHEN ◽

Xiaoxin Susan XU ◽

Jason HARRISON ◽

Gan WANG

Keyword(s):

Dna Repair ◽

Host Cell ◽

Xeroderma Pigmentosum ◽

Normal Fibroblast ◽

Fibroblast Cells ◽

Cross Link ◽

Cell Reactivation ◽

Xeroderma Pigmentosum Group F ◽

Host Cell Reactivation

Many commonly used drugs, such as psoralen and cisplatin, can generate a very unique type of DNA damage, namely ICL (interstrand cross-link). An ICL can severely block DNA replication and transcription and cause programmed cell death. The molecular mechanism of repairing the ICL damage has not been well established. We have studied the role of XPF (xeroderma pigmentosum group F) protein in psoralen-induced ICL-mediated DNA repair and mutagenesis. The results obtained from our mutagenesis studies revealed a very similar mutation frequency in both human normal fibroblast cells and XPF cells. The mutation spectra generated in both cells, however, were very different: most of the mutations generated in the normal fibroblast cells were T167→A transversions, whereas most of the mutations generated in the XPF cells were T167→G transversions. When a wild-type XPF gene cDNA was stably transfected into the XPF cells, the T167→A mutations were increased and the T167→G mutations were decreased. We also determined the DNA repair capability of the XPF cells using both the host-cell reactivation and the in vitro DNA repair assays. The results obtained from the host-cell reactivation experiments revealed an effective reactivation of a luciferase reporter gene from the psoralen-damaged plasmid in the XPF cells. The results obtained from the in vitro DNA repair experiments demonstrated that the XPF nuclear extract is normal in introducing dual incisions during the nucleotide excision repair process. These results suggest that the XPF protein has important roles in the psoralen ICL-mediated DNA repair and mutagenesis.

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