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Effects of benzo[a]pyrene diol epoxide adducts on DNA synthesis in mammalian cells

A Rinaldy, M L Lockhart, J F Deutsch

    Mutation Research
    |June 1, 1982
    PubMed

    Insights

    Benzo[a]pyrene diol epoxide (BPDE) adducts in DNA temporarily block replication in mammalian cells. Cellular repair or bypass mechanisms eventually overcome this blockage, though viral viability remains reduced.

    Area of Science:

    • Molecular Biology
    • Toxicology
    • Virology

    Background:

    • Benzo[a]pyrene diol epoxide (BPDE) is a known carcinogen that forms adducts in DNA.
    • Understanding how DNA adducts affect DNA replication is crucial for assessing their biological impact.

    Purpose of the Study:

    • To investigate the effects of BPDE-DNA adducts on DNA replication in mammalian cells.
    • To elucidate the cellular mechanisms involved in overcoming replication blocks caused by BPDE adducts.

    Main Methods:

    • SV40 virus was treated with BPDE in vitro to create DNA adducts.
    • Mammalian cells were infected with BPDE-treated virus and monitored for replication.
    • Co-infection with a marker virus supplied necessary replication factors.

    Main Results:

    • Replication of BPDE-adducted DNA was initially delayed compared to control DNA.
    • Most or all infected DNA molecules eventually replicated, suggesting a repair or bypass mechanism.
    • Despite eventual replication, BPDE-treated virus showed reduced viability in plaque assays.

    Conclusions:

    • BPDE-DNA adducts pose a significant impediment to DNA synthesis in vivo.
    • Mammalian cells possess mechanisms to repair or bypass BPDE adducts, enabling replication.
    • Persistent defects in transcription or errors in repair/bypass replication likely contribute to reduced viral viability.

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