Ribonucleotide sequence homology among avian oncornaviruses

Area of Science:

• Virology
• Molecular Biology
• Genetics

Background:

• Avian RNA tumor viruses (ARTVs) are a group of retroviruses known to cause various tumors in birds.
• Understanding the genetic relatedness between different ARTVs is crucial for studying viral evolution and pathogenesis.
• Previous studies have indicated some level of sequence homology among ARTV genomes, but the extent and specific relationships were not fully elucidated.

Purpose of the Study:

• To quantify the RNA sequence relatedness among the genomes of different avian RNA tumor viruses.
• To determine the extent of homology between Rous associated virus-0 (RAV-0) and avian myeloblastosis virus (AMV).
• To investigate the hybridization patterns of viral RNA with DNA from normal and leukemic chicken cells.

Main Methods:

• Analysis of DNA-RNA hybrid formation inhibition using 3H-labeled 35S viral RNA and excess unlabeled viral RNA.
• Utilized leukemic and normal chicken cell DNA as hybridization targets.
• Tested Rous associated virus (RAV)-3, AMV, RAV-60, RAV-61, B-77 sarcoma virus, and RAV-0.

Main Results:

• Avian RNA tumor virus genomes exhibit 50-80% homology in nucleotide sequences.
• AMV and RAV-0 genomes share 67-70% homology, with AMV hybridizing to RAV-0-like sequences in normal chicken DNA.
• RAV-60 and RAV-61 RNA hybridized with virus-specific sequences shared by AMV and RAV-0 in leukemic DNA.

Conclusions:

• Significant sequence homology exists among different avian RNA tumor virus genomes.
• RAV-0 and AMV are closely related, sharing a substantial portion of their genetic material.
• The degree of hybridization with normal chicken DNA can be predicted by the homology of viral RNA to RAV-0 RNA.