Polymerase activity of Pichinde virus.

Area of Science:

• Virology
• Molecular Biology
• Biochemistry

Background:

• Pichinde virus belongs to the arenavirus family.
• Understanding viral polymerase activity is crucial for studying viral replication.

Purpose of the Study:

• To investigate the polymerase activity present in purified Pichinde virus.
• To characterize the template, cofactors, and product of this enzymatic activity.

Main Methods:

• Purification of Pichinde virus.
• Assays for RNA-dependent RNA polymerase and RNA-dependent DNA polymerase activity.
• Enzyme inhibition studies using RNase, DNase, and actinomycin D.
• Analysis of the RNA product using sucrose gradient sedimentation.

Main Results:

• Purified Pichinde virus exhibited RNA-dependent RNA polymerase activity.
• The polymerase reaction was inhibited by RNase but not by DNase or actinomycin D, indicating RNA as the template.
• Optimal activity required divalent cations, specifically Mg(2+) and Mn(2+).
• The synthesized RNA product showed partial resistance to RNase, with a sedimentation coefficient of 22-26S.

Conclusions:

• Pichinde virus possesses an intrinsic RNA-dependent RNA polymerase.
• The polymerase uses the viral RNA genome as a template.
• The enzyme's activity is modulated by divalent cations and produces a characteristic RNA product.