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A potassium channel protein encoded by chlorella virus PBCV-1
B Plugge1, S Gazzarrini, M Nelson
1Albrecht-von-Haller-Institut für Pflanzenwissenschaften, Universität Göttingen, 37073 Göttingen, Germany.
Science (New York, N.Y.)
|March 4, 2000
Summary
The large chlorella virus PBCV-1 encodes a novel potassium channel protein, Kcv, essential for its life cycle. This viral channel exhibits potassium selectivity and is inhibited by specific blockers, impacting virus plaque formation.
Area of Science:
- Virology
- Molecular Biology
- Ion Channel Physiology
Background:
- Large chlorella virus PBCV-1 possesses double-stranded DNA (dsDNA).
- Viral genomes can encode proteins with functions previously unknown in viruses.
- Potassium channels are crucial for cellular processes in many organisms.
Purpose of the Study:
- To identify and characterize novel viral proteins.
- To investigate the function of a specific open reading frame (ORF) in PBCV-1.
- To determine if the ORF encodes a functional ion channel.
Main Methods:
- Phylogenetic analysis of the Kcv protein.
- Functional expression of the ORF in Xenopus laevis oocytes.
- Electrophysiological recordings to assess ion conductance.
- Inhibition assays using channel blockers (amantadine, barium, cesium).
- Assessment of virus plaque formation.
Main Results:
- PBCV-1 encodes a 94-codon ORF with a motif similar to potassium channel domains.
- Phylogenetic analysis suggests Kcv is a novel type of potassium channel.
- Functional expression in oocytes revealed a potassium-selective conductance.
- Amantadine and barium inhibited the Kcv-mediated conductance and virus plaque formation.
- Cesium did not inhibit the conductance.
Conclusions:
- PBCV-1 encodes the first identified viral protein functioning as a potassium-selective channel.
- The viral potassium channel (Kcv) is essential for the virus life cycle.
- Kcv represents a new class of ion channels with implications for virology and channel biology.
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