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Single-stranded DNA from oncornavirus-infected cells enriched in virus-specific DNA sequences
Summary
Single-stranded DNA (ss-DNA) fractions from chicken cells contain actively transcribed DNA sequences, including avian myeloblastosis virus (AMV) provirus DNA. This enrichment in ss-DNA suggests selective distribution near transcription sites.
Area of Science:
- Molecular Biology
- Virology
- Genetics
Background:
- Single-stranded DNA (ss-DNA) fractions from native nuclear DNA exhibit hybridization with cellular RNA.
- A significant portion of non-repetitive ss-DNA can hybridize with homologous RNAs.
Purpose of the Study:
- To investigate if ss-DNA enrichment in transcribed sequences involves avian myeloblastosis virus (AMV) provirus DNA.
- To determine the distribution of provirus DNA strands within the ss-DNA fraction of infected cells.
Main Methods:
- Hybridization of radioactive AMV RNA and complementary DNA (cDNA) copies to ss-DNA and bulk DNA from infected chicken cells.
- Kinetic analysis of hybridization using actinomycin D to differentiate DNA strand presence.
Main Results:
- ss-DNA from AMV-infected cells showed faster hybridization with AMV RNA compared to bulk DNA.
- Double-stranded cDNA hybridized significantly faster to ss-DNA than to total DNA, indicating preferential presence of one provirus DNA strand.
- Single-stranded cDNA showed minimal annealing to ss-DNA compared to bulk DNA.
Conclusions:
- Actively transcribed DNA sequences, including AMV provirus DNA, are selectively enriched in the ss-DNA fraction.
- This selective distribution is likely due to single-strand breaks occurring near transcription sites.