All intact subunit RNAs from Rous sarcoma virus contain poly (A)

Area of Science:

• Molecular Biology
• Virology
• RNA Biochemistry

Background:

• Schmidt-Ruppin Rous sarcoma virus (SRRSV) is an oncogenic retrovirus.
• Viral RNA subunits are crucial for viral replication and infectivity.
• Understanding RNA-binding properties is key to deciphering viral mechanisms.

Purpose of the Study:

• To investigate the binding capacity of SRRSV RNA subunits to deoxythymidine oligonucleotides ((dT)n).
• To characterize the nature of RNA subunits that do not bind (dT)n.
• To correlate subunit integrity with (dT)n binding ability.

Main Methods:

• Cesium sulfate density gradient centrifugation
• Sucrose gradient centrifugation
• Polyacrylamide gel electrophoresis (PAGE)
• Molecular weight distribution analysis

Main Results:

• Two distinct classes of SRRSV RNA subunits were identified based on (dT)n binding.
• 60-70% of purified subunits demonstrated the ability to bind (dT)n.
• Nonbinding RNA subunits were characterized as fragments lacking the riboadenylic acid (rA)n terminus, resulting from nucleolytic cleavage.
• Intact subunit RNA from early virus harvests showed a higher propensity for (dT)n binding.

Conclusions:

• The integrity of the riboadenylic acid (rA)n terminus is essential for (dT)n binding in SRRSV RNA subunits.
• Nucleolytic degradation leads to the formation of nonbinding RNA fragments.
• Early harvest virus provides a source of more intact RNA subunits with higher binding efficiency.