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Analysis of the myeloproliferative sarcoma virus genome: limited changes in the prototype lead to altered target cell
Abstract:
The myeloproliferative sarcoma virus (MPSV) derived from Moloney sarcoma virus (MSV-Mol) is a unique sarcoma virus which causes expansion of the hematopoietic stem cell compartment as well as the erythroid and myeloid cell lineages. MPSV also induces spleen focus formation in adult mice as do Friend and Rauscher viruses. Analysis of the MPSV genome on methyl mercury gels showed that the genome size is 7.0 kilobases, which is larger than the defective genome of any known MSV-Mol isolate. Hybridization analysis with specific cDNA probes showed that MPSV is a modified sarcoma virus with no sequences in the unique region of the defective sarcoma genome related to unique Friend virus sequences. The only viral sequences in the defective genome other than helper virus-related sequences are derived from the Moloney sarcoma virus genome with no new cellular sequences added. There was no evidence for induction of xenotropic virus sequences in MPSV-infected spleens of DBA/2J mice, indicating that spleen focus formation can be obtained by different mechanisms.
Insights
Myeloproliferative sarcoma virus (MPSV) causes hematopoietic stem cell expansion and spleen focus formation in mice. Its larger genome, derived solely from Moloney sarcoma virus (MSV-Mol), differs from Friend virus, suggesting diverse spleen focus mechanisms.
Area of Science:
- Virology
- Molecular Biology
- Oncology
Background:
- Myeloproliferative sarcoma virus (MPSV), derived from Moloney sarcoma virus (MSV-Mol), is a unique retrovirus.
- MPSV induces hematopoietic stem cell expansion and spleen focus formation, similar to Friend and Rauscher viruses.
Purpose of the Study:
- To characterize the genomic structure and origin of MPSV.
- To investigate the mechanism of spleen focus formation induced by MPSV.
Main Methods:
- Genome size analysis using methyl mercury gel electrophoresis.
- Hybridization analysis with specific cDNA probes.
- Analysis of MPSV-infected mouse spleens for viral sequences.
Main Results:
- MPSV possesses a 7.0 kilobase genome, larger than known MSV-Mol isolates.
- MPSV contains Moloney sarcoma virus sequences but lacks unique Friend virus sequences.
- No evidence of xenotropic virus induction was found in MPSV-infected mouse spleens.
Conclusions:
- MPSV is a modified Moloney sarcoma virus with a distinct genomic composition.
- Spleen focus formation can occur through mechanisms independent of xenotropic virus induction.