Physical map of biologically active Harvey sarcoma virus unintegrated linear DNA

Area of Science:

• Molecular Biology
• Virology
• Genetics

Background:

• Murine leukemia virus (MuLV) is a retrovirus.
• Harvey sarcoma virus (HSV) is a replication-defective retrovirus that requires a helper virus for propagation.
• Understanding the genetic makeup and biological activity of viral DNA is crucial in virology.

Purpose of the Study:

• To characterize the unintegrated Harvey sarcoma virus (HSV) DNA in infected cells.
• To determine the biological activity of HSV DNA in transforming mouse fibroblasts.
• To compare the physical map of HSV DNA with that of Moloney murine leukemia virus (MuLV).

Main Methods:

• Infection of BALB/c JLS V9 cells with the Harvey sarcoma virus-murine leukemia virus (HSV-MuLV) complex.
• Isolation and characterization of unintegrated viral DNA species.
• Transfection of NIH 3T3 mouse fibroblasts with HSV DNA.
• Restriction endonuclease mapping of HSV DNA.
• Comparison of physical maps of HSV and Moloney MuLV DNA.

Main Results:

• Unintegrated HSV linear DNA (6.0-kilobase pair) and circular DNA species were detected in infected cells, along with MuLV DNA.
• HSV linear DNA induced focal transformation in NIH 3T3 cells without helper MuLV functions.
• A physical map of HSV DNA was established, revealing identity with Moloney MuLV DNA near the viral RNA 3' ends.

Conclusions:

• The 6.0-kilobase pair HSV DNA is biologically active and capable of inducing cell transformation independently of helper MuLV.
• The HSV genome shares significant structural homology with Moloney MuLV, particularly in the region near the 3' end of the viral RNA.
• These findings contribute to understanding the genetic organization and transforming potential of retroviral DNA.