Nucleolin Interacts with the Feline Calicivirus 3′ Untranslated Region and the Protease-Polymerase NS6 and NS7 Proteins, Playing a Role in Virus Replication

• DOI: 10.1128/jvi.01878-10
• Publication Date: 2011-06-17T03:15:39Z
• Authors: Clotilde Cancio-L...; Martha Yocupicio-...; Carlos Sandoval-J...; Iván Galvan-Mendoza; Luis Ureña; Surender Vashist; Ian Goodfellow; Juan Salas-Benito; Ana Lorena Gutiér...
• Keywords: Nucleolin; 0301 basic medicine; RNA-Binding Proteins; Kidney; Phosphoproteins; Virus Replication; Cell Line; 3. Good health; Norwalk virus; Viral Proteins; 03 medical and health sciences; Cats; Animals; RNA, Viral; RNA Interference; RNA, Messenger; RNA, Small Interfering; 3' Untranslated Regions; Calicivirus, Feline; Peptide Hydrolases

ABSTRACT

Cellular proteins play many important roles during the life cycle of all viruses. Specifically, host cell nucleic acid-binding proteins interact with viral components of positive-stranded RNA viruses and regulate viral translation, as well as RNA replication. Here, we report that nucleolin, a ubiquitous multifunctional nucleolar shuttling phosphoprotein, interacts with the Norwalk virus and feline calicivirus (FCV) genomic 3′ untranslated regions (UTRs). Nucleolin can also form a complex in vitro with recombinant Norwalk virus NS6 and -7 (NS6/7) and can be copurified with the analogous protein from feline calicivirus (p76 or NS6/7) from infected feline kidney cells. Nucleolin RNA levels or protein were not modified during FCV infection; however, as a consequence of the infection, nucleolin was seen to relocalize from the nucleoli to the nucleoplasm, as well as to the perinuclear area where it colocalizes with the feline calicivirus NS6/7 protein. In addition, antibodies to nucleolin were able to precipitate viral RNA from feline calicivirus-infected cells, indicating a direct or indirect association of nucleolin with the viral RNA during virus replication. Small interfering RNA (siRNA)-mediated knockdown of nucleolin resulted in a reduction of the cytopathic effect and virus yield in CrFK cells. Taken together, these results demonstrate that nucleolin is a nucleolar component that interacts with viral RNA and NS6/7 and is required for feline calicivirus replication.