title: Efficient induction of nuclear aggresomes by specific single missense mutations in the DNA-binding domain of a viral AP-1 homolog.
abstract: Nuclear aggresomes induced by proteins containing an expanded polyglutamine (polyQ) tract are pathologic hallmarks of certain neurodegenerative diseases. Some GFP fusion proteins lacking a polyQ tract may also induce nuclear aggresomes in cultured cells. Here we identify single missense mutations within the basic DNA recognition region of Bam HI Z E B virus replication activator (ZEBRA), an Epstein-Barr virus (EBV)-encoded basic zipper protein without a polyQ tract, that efficiently induced the formation of nuclear aggresomes. Wild-type (WT) ZEBRA was diffusely distributed within the nucleus. Four non-DNA-binding mutants, Z(R179E), Z(R183E), Z(R190E), and Z(K178D) localized to the periphery of large intranuclear spheres, to discrete nuclear aggregates, and to the cytoplasm. Other non-DNA-binding mutants, Z(N182K), Z(N182E), and Z(S186E), did not exhibit this phenotype. The interior of the spheres contained promyelocytic leukemia and HSP70 proteins. ZEBRA mutants directly induced the nuclear aggresome pathway in cells with and without EBV. Specific cellular proteins (SC35 and HDAC6) and viral proteins (WT ZEBRA, Rta, and BMLF1) but not other cellular or viral proteins were recruited to nuclear aggresomes. Co-transfection of WT ZEBRA with aggresome-inducing mutants Z(R183E) and Z(R179E) inhibited late lytic viral protein expression and lytic viral DNA amplification. This is the first reported instance in which nuclear aggresomes are induced by single missense mutations in a viral or cellular protein. We discuss conformational changes in the mutant viral AP-1 proteins that may lead to formation of nuclear aggresomes.
authors.affiliation: Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: Park
authors.forename: Ruth
authors.initials: R
authors.lastname: Wang'ondu
authors.forename: Lee
authors.initials: L
authors.lastname: Heston
authors.forename: Duane
authors.initials: D
authors.lastname: Shedd
authors.forename: George
authors.initials: G
authors.lastname: Miller
mesh_terms: D019943:Amino Acid Substitution; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism* / Q000821:virology; D004279:DNA, Viral / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D004854:Herpesvirus 4, Human / Q000235:genetics / Q000378:metabolism*; D000073864:Histone Deacetylase 6; D006655:Histone Deacetylases / Q000235:genetics / Q000378:metabolism; D006801:Humans; D020125:Mutation, Missense; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D012261:Ribonucleoproteins / Q000235:genetics / Q000378:metabolism; D000068103:Serine-Arginine Splicing Factors; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D018808:Transcription Factor AP-1; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: C063676:BZLF1 protein, Herpesvirus 4, Human; D004279:DNA, Viral; D009687:Nuclear Proteins; D010750:Phosphoproteins; D012261:Ribonucleoproteins; C090236:SM protein, Human herpesvirus 4; D015534:Trans-Activators; D018808:Transcription Factor AP-1; D014764:Viral Proteins; C073288:SRSF2 protein, human; D000068103:Serine-Arginine Splicing Factors; C433811:HDAC6 protein, human; D000073864:Histone Deacetylase 6; D006655:Histone Deacetylases