Site-specific mutagenesis in human cells by bulky exocyclic amino-substituted guanine and adenine derivatives.
Cancer Res Treat
; 36(2): 151-6, 2004 Apr.
Article
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| MEDLINE
| ID: mdl-20396556
ABSTRACT
PURPOSE:
7-Bromomethylbenz[a]anthracene is a well-known mutagen and carcinogen. The aim of this study is to determine the mutagenic potency of its two major DNA adducts [N(2)-(benz[a]anthracen-7-ylmethyl)-2'-deoxyguanosine (b[a]a(2)G) and N(6)-(benz[a]anthracen-7-ylmethyl)-2'-deoxyadenosine (b[a]a(6)A)] and the simpler benzylated analogs [N(2)-benzyl-2'-deoxyguanosine (bn(2)G) and N(6)-benzyl-2'-deoxyadenosine (bn(6)A)] in Ad293 human cells and to compare to their mutagenicity in human cells and E. coli. MATERIALS ANDMETHODS:
The shuttle vector pGP50 is capable of replicating in E. coli and human cells. Modified nucleotides were positioned in the plasmid pGP50 in a manner similar to pGP10 as described (8). Adenovirus transformed human embryonic kidney cells (line 293) were transfected with a shuttle vector containing an adduct. Two days later, the plasmids were recovered and treated with DpnI to remove unreplicated DNA. DH10B E. coli were transformed with the plasmids. Bacteria were cultured with the media containing X-gal, IPTG and ampicillin. Bacteria transformed by the plasmid with the adduct-induced mutation in the initiation codon of lacZ' form white colonies whereas bacteria transformed by the plasmid without mutation form blue colonies.RESULTS:
In the human cell site-specific mutagenesis system, bn(2)G exhibited weak mutagenicity and bn(6)A was not mutagenic, although b[a]a(2)G or b[a]a(6)A produced 8% and 7% mutant colonies, respectively. At the site of the adduct, b[a]a(2)G induced the G-->T transversion mutation while b[a]a(6)A produced the A-->G transition mutation.CONCLUSION:
These data indicate that bulkier b[a]a(2)G and b[a]a(6)A exhibit significantly greater mutagenicity in human cells than in E. coli.
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Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
Cancer Res Treat
Año:
2004
Tipo del documento:
Article