Identification of the nuclear and nucleolar localization signals of the Feline immunodeficiency virus Rev protein

• Published in: Virus research 2020-12, Vol.290, p.198153-198153, Article 198153
• Main Authors: Marchand, Claude, Lemay, Guy, Archambault, Denis
• Format: Article
• Language: English
• Subjects: Feline immunodeficiency virus; Lentivirus; Nuclear localization signal; Nucleolar localization signal; Rev protein; RNA export
• ISSN: 0168-1702; 1872-7492
• DOI: 10.1016/j.virusres.2020.198153

•Nuclear/nucleolar localization signals (NLS/NoLS) were mapped between amino acids 82 and 99 of the FIV Rev protein.•The high content of basic residues that compose the NoLS results in a strong nucleolar retention of the FIV Rev protein.•The NoLS of the FIV Rev protein is intrinsically associated with the Rev protein NLS. Lentivirus genomes code for a regulatory protein essential for virus replication termed Rev. The Rev protein binds to partially spliced and unspliced viral RNAs and mediates their nuclear export. Therefore, Rev possesses functional domains that enable its shuttling between the cytoplasm and the nucleus. The Feline immunodeficiency virus (FIV), a lentivirus, can lead to an immunodeficiency syndrome after a long incubation period, similar to that associated with the human immunodeficiency virus type 1 (HIV-1). The FIV Rev functional domains have been predicted only by homology with those of HIV-1 Rev. In the present study, the nuclear and nucleolar localization signals (NLS and NoLS, respectively) of the FIV Rev were examined. A series of FIV Rev deletion mutants fused to the enhanced green fluorescent protein (EGFP) were used to localize the NLS in a region spanning amino acids (aa) 81–100. By using alanine substitution mutants, basic residues present between the amino acids (aa) 84–99 of the FIV Rev protein sequence were identified to form the NLS, whereas those between aa 82–95 were associated with the NoLS function. These results further enhance our understanding of how Rev exerts its role in the replication cycle of lentiviruses.