CHARACTERIZATION OF THE H1N1 INFLUENZA A NS2 SUBCELLULAR LOCALIZATION AND INTERACTION WITH NUCLEAR PROTEINS

Abstract

RECENT STUDIES SUGGEST THAT A CRITICAL STEP DURING VIRAL REPLICATION IN THE NUCLEUS INVOLVES THE NUCLEOLUS, WHICH IS THE LARGEST SUBNUCLEAR STRUCTURE IN THE CELL. HOWEVER, THE MECHANISMS BY WHICH VIRAL PROTEINS LOCALIZE TO THE NUCLEOLUS AND THE FUNCTIONS THEY PERFORM THERE HAVE NOT BEEN FULLY ELUCIDATED. WE HAVE CHOSEN TO STUDY THE NON-STRUCTURAL PROTEIN 2 (NS2) OF THE H1N1 SUBTYPE OF THE INFLUENZA A VIRUS. ITS PRIMARY FUNCTION IS TO FACILITATE NUCLEAR EXPORT OF VRNPS. WE OBSERVED THAT NS2 LOCALIZES TO THE NUCLEOLUS IN A UNIQUE GRANULAR MANNER AND CHARACTERIZED A BIPARTITE NOLS CONSISTING OF RESIDUES 16-23 AND 45-72. WE DISCOVERED THREE POTENTIAL BINDING PARTNERS FROM HELA NUCLEAR LYSATE: B23, H1.2 AND HMGB1. HMGB1 HAD A LOWER BINDING AFFINITY TO NS2 AS COMPARED TO B23 AND H1.2. IT WAS FOUND THAT NS2 DOES NOT SIGNIFICANTLY INHIBIT RRNA SYNTHESIS IN THE CELL AND DOES NOT SIGNIFICANTLY AFFECT THE CELL CYCLE.