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Formation of cellular deoxyribonucleic acid during productive polyoma virus infection
Abstract:
It was previously shown that the majority of deoxyribonucleic acid (DNA) made in growing mouse embryo cells productively infected at low multiplicity with polyoma virus is cellular in nature and that some of this cell DNA contains discontinuities in the newly synthesized strand. Evidence obtained indicates the following. (i) Induction of cell DNA synthesis precedes the onset of detectable viral DNA replication by approximately 3 hr. (ii) Double-stranded cell DNA molecules, discontinuous in the newly synthesized strands, arise by direct synthesis (rather than by degradation of a high-molecular-weight precursor) only in the cell DNA replicated after initiation of viral DNA synthesis. (iii) This DNA component is continuously formed throughout the "late" stage of infection and is continuously converted into apparently normal cell DNA of high molecular weight without prior degradation to acid-soluble components.
Insights
Polyoma virus infection induces new mouse cell DNA synthesis, creating discontinuities in newly synthesized strands. This altered DNA is then converted into normal high-molecular-weight cell DNA during infection.
Area of Science:
- Molecular Biology
- Virology
- Cell Biology
Background:
- Growing mouse embryo cells infected with polyoma virus produce mostly cellular deoxyribonucleic acid (DNA).
- Some newly synthesized cellular DNA contains strand discontinuities during productive polyoma virus infection.
Purpose of the Study:
- To investigate the temporal relationship between viral DNA replication and the synthesis of discontinuous cell DNA.
- To determine the origin and fate of cell DNA with strand discontinuities during polyoma virus infection.
Main Methods:
- Monitoring DNA synthesis in infected mouse embryo cells.
- Analyzing the structure of newly synthesized cell DNA using techniques to detect strand discontinuities.
- Tracking the conversion of discontinuous cell DNA to high-molecular-weight DNA.
Main Results:
- Cellular DNA synthesis is induced approximately 3 hours before viral DNA replication begins.
- Discontinuities in newly synthesized DNA strands arise directly during replication after viral DNA synthesis initiates.
- This DNA component is continuously generated and converted to normal high-molecular-weight DNA throughout the late stage of infection.
Conclusions:
- Polyoma virus infection triggers specific alterations in cellular DNA replication.
- Discontinuous cell DNA is an intermediate product formed during viral infection and is subsequently repaired.