HEPATITIS-C VIRUS NS5B PROTEIN IS A MEMBRANE-ASSOCIATED PHOSPHOPROTEIN WITH A PREDOMINANTLY PERINUCLEAR LOCALIZATION

Hepatitis C virus NS5B protein is an RNA-dependent RNA polymerase. To investigate the properties and function of this protein, we have expre ssed the NS5B protein in insect and mammalian cells. NS5B was found to be present as fine speckles in the cytoplasm, particularly concentrat ed in the perinuclear region, suggesting its association with the nucl ear membrane, the endoplasmic reticulum, or the Golgi complex. This co nclusion was supported by the biochemical demonstration that NS5B was associated with the membranes in the cells. Furthermore, it was shown that NS5B protein is a phosphoprotein. These properties may be related to its function as an RNA polymerase. (C) 1997 Academic Press