Plant Pathology Department


Date of this Version



Published in Science 287 (March 3, 2000), pp. 1641–1644; doi 10.1126/science.287.5458.1641 Copyright © 2000 by the American Association for the Advancement of Science. Used by permission.


The large chlorella virus PBCV-1, which contains double-stranded DNA (dsDNA), en¬codes a 94-codon open reading frame (ORF) that contains a motif resembling the signature se¬quence of the pore domain of potassium channel proteins. Phylogenetic analyses of the encoded protein, Kcv, indicate a previously unidentified type of potassium channel. The messenger RNA encoded by the ORF leads to functional expression of a potassium-selective conductance in Xen¬opus laevis oocytes. The channel blockers amantadine and barium, but not cesium, inhibit this conductance, in addition to virus plaque formation. Thus, PBCV-1 encodes the first known viral protein that functions as a potassium-selective channel and is essential in the virus life cycle.