Abstract
Benzene is a human leukemia carcinogen, resulting from its cellular metabolism. A major benzene metabolite is p-benzoquinone (pBQ), which can damage DNA by forming the exocyclic base adducts pBQ-dC, pBQ-dA, and pBQ-dG in vitro. To gain insights into the role of pBQ in benzene genotoxicity, we examined in vitro translesion synthesis and in vivo mutagenesis of these pBQ adducts. Purified REV1 and Polκ were essentially incapable of translesion synthesis in response to the pBQ adducts. Opposite pBQ-dA and pBQ-dC, purified human Polι was capable of error-prone nucleotide insertion, but was unable to perform extension synthesis. Error-prone translesion synthesis was observed with Polη. However, DNA synthesis largely stopped opposite the lesion. Consistent with in vitro results, replication of site-specifically damaged plasmids was strongly inhibited by pBQ adducts in yeast cells, which depended on both Polζ and Polη. In wild-type cells, the majority of translesion products were deletions at the site of damage, accounting for 91%, 90%, and 76% for pBQ-dA, pBQ-dG, and pBQ-dC, respectively. These results show that the pBQ-dC, pBQ-dA, and pBQ-dG adducts are strong blocking lesions, and are highly mutagenic by predominantly inducing deletion mutations. These results are consistent with the lesion structures predicted by molecular dynamics simulation. Our results led to the following model. Translesion synthesis normally occurs by directly copying the lesion site through base insertion and extension synthesis. When the lesion becomes incompatible in accommodating a base opposite the lesion in DNA, translesion synthesis occurs by a less efficient lesion loop-out mechanism, resulting in avoiding copying the damaged base and leading to deletion.
| Original language | English |
|---|---|
| Pages (from-to) | 1399-1409 |
| Number of pages | 11 |
| Journal | DNA Repair |
| Volume | 4 |
| Issue number | 12 |
| DOIs | |
| State | Published - Dec 8 2005 |
| Externally published | Yes |
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Keywords
- Benzene
- DNA adducts
- Lesion bypass
- Mutagenesis
- Polymerase ζ
- Translesion synthesis
- Y family DNA polymerase
ASJC Scopus subject areas
- Biochemistry
- Molecular Biology
Cite this
The p-benzoquinone DNA adducts derived from benzene are highly mutagenic. / Xie, Zhongwen; Zhang, Yanbin; Guliaev, Anton B.; Shen, Huiyun; Hang, Bo; Singer, B.; Wang, Zhigang.
In: DNA Repair, Vol. 4, No. 12, 08.12.2005, p. 1399-1409.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - The p-benzoquinone DNA adducts derived from benzene are highly mutagenic
AU - Xie, Zhongwen
AU - Zhang, Yanbin
AU - Guliaev, Anton B.
AU - Shen, Huiyun
AU - Hang, Bo
AU - Singer, B.
AU - Wang, Zhigang
PY - 2005/12/8
Y1 - 2005/12/8
N2 - Benzene is a human leukemia carcinogen, resulting from its cellular metabolism. A major benzene metabolite is p-benzoquinone (pBQ), which can damage DNA by forming the exocyclic base adducts pBQ-dC, pBQ-dA, and pBQ-dG in vitro. To gain insights into the role of pBQ in benzene genotoxicity, we examined in vitro translesion synthesis and in vivo mutagenesis of these pBQ adducts. Purified REV1 and Polκ were essentially incapable of translesion synthesis in response to the pBQ adducts. Opposite pBQ-dA and pBQ-dC, purified human Polι was capable of error-prone nucleotide insertion, but was unable to perform extension synthesis. Error-prone translesion synthesis was observed with Polη. However, DNA synthesis largely stopped opposite the lesion. Consistent with in vitro results, replication of site-specifically damaged plasmids was strongly inhibited by pBQ adducts in yeast cells, which depended on both Polζ and Polη. In wild-type cells, the majority of translesion products were deletions at the site of damage, accounting for 91%, 90%, and 76% for pBQ-dA, pBQ-dG, and pBQ-dC, respectively. These results show that the pBQ-dC, pBQ-dA, and pBQ-dG adducts are strong blocking lesions, and are highly mutagenic by predominantly inducing deletion mutations. These results are consistent with the lesion structures predicted by molecular dynamics simulation. Our results led to the following model. Translesion synthesis normally occurs by directly copying the lesion site through base insertion and extension synthesis. When the lesion becomes incompatible in accommodating a base opposite the lesion in DNA, translesion synthesis occurs by a less efficient lesion loop-out mechanism, resulting in avoiding copying the damaged base and leading to deletion.
AB - Benzene is a human leukemia carcinogen, resulting from its cellular metabolism. A major benzene metabolite is p-benzoquinone (pBQ), which can damage DNA by forming the exocyclic base adducts pBQ-dC, pBQ-dA, and pBQ-dG in vitro. To gain insights into the role of pBQ in benzene genotoxicity, we examined in vitro translesion synthesis and in vivo mutagenesis of these pBQ adducts. Purified REV1 and Polκ were essentially incapable of translesion synthesis in response to the pBQ adducts. Opposite pBQ-dA and pBQ-dC, purified human Polι was capable of error-prone nucleotide insertion, but was unable to perform extension synthesis. Error-prone translesion synthesis was observed with Polη. However, DNA synthesis largely stopped opposite the lesion. Consistent with in vitro results, replication of site-specifically damaged plasmids was strongly inhibited by pBQ adducts in yeast cells, which depended on both Polζ and Polη. In wild-type cells, the majority of translesion products were deletions at the site of damage, accounting for 91%, 90%, and 76% for pBQ-dA, pBQ-dG, and pBQ-dC, respectively. These results show that the pBQ-dC, pBQ-dA, and pBQ-dG adducts are strong blocking lesions, and are highly mutagenic by predominantly inducing deletion mutations. These results are consistent with the lesion structures predicted by molecular dynamics simulation. Our results led to the following model. Translesion synthesis normally occurs by directly copying the lesion site through base insertion and extension synthesis. When the lesion becomes incompatible in accommodating a base opposite the lesion in DNA, translesion synthesis occurs by a less efficient lesion loop-out mechanism, resulting in avoiding copying the damaged base and leading to deletion.
KW - Benzene
KW - DNA adducts
KW - Lesion bypass
KW - Mutagenesis
KW - Polymerase ζ
KW - Translesion synthesis
KW - Y family DNA polymerase
UR - http://www.scopus.com/inward/record.url?scp=27844460203&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=27844460203&partnerID=8YFLogxK
U2 - 10.1016/j.dnarep.2005.08.012
DO - 10.1016/j.dnarep.2005.08.012
M3 - Article
C2 - 16181813
AN - SCOPUS:27844460203
VL - 4
SP - 1399
EP - 1409
JO - DNA Repair
JF - DNA Repair
SN - 1568-7864
IS - 12
ER -