Two nucleolar targeting signals present in the N-terminal part of Semliki Forest virus capsid protein.

Here we show that the capsid (C) protein of Semliki Forest virus (SFV) contains two nucleolar targeting signals (NOS) responsible for the karyophilic properties of this protein. When conjugated to the non-karyophilic carrier protein bovine serum albumin (BSA), the two synthetic nuclear localization sequences (NLS) of the C protein transferred with equal efficiency the carrier protein into the nucleolus of both higher and lower eukaryotic target cells.