Rous sarcoma virus genome is terminally redundant: the 5' sequence

Area of Science:

• Molecular Biology
• Virology
• Genetics

Background:

• Rous sarcoma virus (RSV) replication involves reverse transcription of its RNA genome into DNA.
• A tRNA molecule serves as a primer for reverse transcriptase, initiating DNA synthesis near the 5' end of the viral RNA.
• The initial DNA product is a 'run-off' fragment extending from the primer to the 5' terminus of the RNA template.

Purpose of the Study:

• To determine the nucleotide sequence of the first 101 bases at the 5' end of the Rous sarcoma virus genome (Prague strain, subgroup C).
• To investigate the implications of this sequence for viral replication mechanisms.

Main Methods:

• Analysis of the DNA molecule generated by reverse transcription of Rous sarcoma virus RNA.
• Sequencing of the initial 101-base DNA product.

Main Results:

• The first 101 bases of the RSV genome were sequenced.
• A 21-base sequence at the extreme 5' end was found to be identical to a sequence at the 3' end, indicating terminal redundancy.
• The sequence analysis revealed a potential ribosome binding site and secondary structures suggestive of a 5'-5' linkage mechanism for viral RNA molecules.

Conclusions:

• Rous sarcoma virus possesses terminal redundancy in its genome, with a 21-base repeat at both ends.
• This terminal redundancy likely facilitates the circularization of the viral DNA during reverse transcription.
• The identified sequence features suggest potential roles in viral RNA processing and genome replication.