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Updated: Jul 22, 2026
Amplification, Next-generation Sequencing, and Genomic DNA Mapping of Retroviral Integration Sites
Published on: March 22, 2016
The integration sites of endogenous and exogenous Moloney murine leukemia virus
Abstract:
Specific cDNA probes of Moloney and AKR murine leukemia viruses have been prepared to characterize the proviral integration sites of these viruses in the genomes of Balb/Mo and Balb/c mice. The genetically transmitted Moloney provirus of Balb/Mo mice was detected in a characteristic Eco RI DNA fragment of 16 x 10(6) daltons. No fragment of this size was detected in tissue DNAs from Balb/c mice infected as newborns with Moloney virus. We conclude that a viral integration site, occupied in preimplantation mouse embryos, is not necessarily occupied when virus infects cells in post-natal animals. Balb/Mo and Balb/c mice do carry the AkR structural gene in an Eco RI DNA fragment of 12 x 10(6) daltons. Further restriction analysis of this fragment indicated that both mouse lines carry one AKR-type provirus. Leukemogenesis in Balb/Mo and newborn infected Balb/c mice is accompanied by reintegration of Moloney viral sequences in new chromosomal sites of tumor tissues. Part of the reintegrated Moloney viral sequences are of subgenomic size. The AKR viral sequences, however, are not found in new sites. Further restriction analysis revealed that the development of Moloney virus-induced leukemia in Balb/Mo mice does not lead to detectable structural alteration of the genetically transmitted Moloney and AKR structural genes. Possible mechanisms of the reintegration process are also discussed.
Insights
Moloney murine leukemia virus integration sites differ between genetically predisposed and infected mice. Leukemia development involves Moloney proviral DNA reintegration into new sites in tumor tissues.
Area of Science:
- Virology
- Genetics
- Oncology
Background:
- Murine leukemia viruses (MLVs) are retroviruses known to cause leukemia in mice.
- Understanding MLV proviral integration is crucial for studying leukemogenesis.
- Genetic predisposition and viral infection influence integration patterns.
Purpose of the Study:
- To characterize Moloney and AKR MLV proviral integration sites in Balb/Mo and Balb/c mouse genomes.
- To investigate the relationship between viral integration and Moloney virus-induced leukemia.
- To compare integration patterns in genetically transmitted versus acquired infections.
Main Methods:
- Preparation of specific cDNA probes for Moloney and AKR MLVs.
- Restriction enzyme digestion (Eco RI) and Southern blot analysis of mouse genomic DNA.
- Analysis of proviral DNA integration sites in normal and tumor tissues.
Main Results:
- Genetically transmitted Moloney provirus in Balb/Mo mice was found at a specific 16 x 10(6) dalton Eco RI fragment.
- This specific fragment was absent in Balb/c mice infected neonatally with Moloney virus.
- Leukemogenesis in both mouse models involved Moloney viral sequence reintegration into new chromosomal sites in tumor tissues.
- AKR proviral sequences were consistently found in a 12 x 10(6) dalton Eco RI fragment in both mouse lines, without evidence of new integration sites.
Conclusions:
- Viral integration sites occupied in germline are not necessarily occupied upon post-natal infection.
- Moloney virus-induced leukemia is associated with proviral DNA reintegration into new genomic locations.
- The genetically transmitted AKR provirus appears stable and not directly involved in Moloney-induced leukemogenesis through integration site alterations.
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