A mutant v-rel with increased ability to transform B lymphocytes

Area of Science:

• Molecular Biology
• Virology
• Oncology

Background:

• Two strains of REV-T (Reticuloendotheliosis virus strain T) exhibit differential bursal cell transformation capabilities.
• REV-TW, a wild-type strain, fails to induce bursal cell colonies, while REV-S2A3 readily transforms them.

Purpose of the Study:

• To investigate the molecular basis for the differential transforming activity of REV-T strains.
• To identify specific mutations in the v-rel oncogene responsible for enhanced bursal cell transformation.

Main Methods:

• Polymerase Chain Reaction (PCR) was used to clone and amplify the v-rel gene from REV-S2A3.
• Site-directed mutagenesis and gene exchange experiments were performed to assess the functional impact of identified mutations.
• In vitro transformation assays using bursal cells and splenocytes were conducted.

Main Results:

• A G-to-T transversion mutation at position 40 of v-rel, changing alanine to serine, was identified in the highly transforming REV-S2A3 strain.
• Mutant viruses with the alanine-to-serine substitution at position 40 of v-Rel demonstrated enhanced ability to form bursal cell colonies in vitro.
• Wild-type viruses induced non-B-cell colonies, whereas mutant viruses predominantly generated B-cell colonies.

Conclusions:

• The substitution of serine for alanine at position 40 of v-Rel significantly enhances the transforming potential of REV-T for B lymphocytes.
• This mutation, located near the DNA-binding region, increases kappa B-binding activity, correlating with enhanced transformation.
• The findings highlight the critical role of specific v-Rel mutations in B-cell lymphomagenesis.