Mapping of putative transforming sequences of EBV DNA

Area of Science:

• Virology
• Molecular Biology
• Genetics

Background:

• Epstein-Barr virus (EBV) causes infectious mononucleosis and is linked to various cancers.
• Understanding EBV's transforming capacity is crucial for developing targeted therapies.
• EBV strains differ in their ability to transform lymphocytes into lymphoblasts.

Purpose of the Study:

• To identify the specific EBV DNA sequences responsible for lymphocyte transformation.
• To compare the DNA of transforming EBV strains with the non-transforming HR-1 strain.
• To map the DNA encoding viral RNA in latently infected cells.

Main Methods:

• Restriction enzyme digestion and fragment analysis of EBV DNA.
• Comparison of DNA fragment profiles between transforming and non-transforming EBV strains.
• Identification and mapping of polyadenylated viral RNA in infected cells.

Main Results:

• The non-transforming EBV HR-1 strain lacks DNA fragments (HsuI B, EcoRI J-K, A) present in transforming strains.
• These deleted DNA sequences in HR-1 are estimated to be 2-3 x 10^6 daltons.
• Viral RNA in latently infected cells is encoded by EBV DNA fragments HsuI A and B, located near the deleted region in HR-1.

Conclusions:

• The absence of specific DNA sequences in the HR-1 strain likely accounts for its lack of transforming ability.
• The identified viral RNA encoding regions are adjacent to, and possibly overlap with, the DNA segment missing in the non-transforming strain.
• These findings provide insights into the genetic basis of EBV-induced lymphoblast transformation.