Rubella virus E2 signal peptide is required for perinuclear localization of capsid protein and virus assembly

The rubella virus (RV) structural proteins capsid, E2, and El are synthesiz ed as a polyprotein precursor. The signal peptide that initiates translocat ion of E2 into the lumen of the endoplasmic reticulum remains attached to t he carboxy terminus of the capsid protein after cleavage by signal peptidas e. Among togaviruses, this feature is unique to RV. The E2 signal peptide h as previously been shown to function as a membrane anchor for the capsid pr otein. In the present study, we demonstrate that this domain is required fo r RV glycoprotein-dependent localization of the capsid protein to the juxta nuclear region and subsequent virus assembly at the Golgi complex.