title: MMTV accessory factor Naf affects cellular gene expression.
abstract: Mouse mammary tumour virus (MMTV) encodes a viral superantigen (Sag) and a negative acting factor (Naf) which share parts of their coding sequence. Using 2-dimensional gel electrophoresis (2D-DIGE), we could show that at least 10 different cellular proteins were differentially expressed in Naf positive cells. Also, luciferase reporter expression was down-regulated in Naf expressing cells independent of the promoter used and further experiments suggested that this effect was due in part to a decrease in cellular growth rates. Although in Naf positive cells expression of the major sag containing transcript was strongly induced by the synthetic glucocorticoid dexamethasone, the hormone analogue neither influenced luciferase expression nor mRNA expression of selected cellular proteins identified by 2D-DIGE. Taken together, these data support the previous finding that Naf and Sag have separable activities and suggest that Naf may play a role in modulating host cell gene expression during MMTV infection.
authors.affiliation: Research Institute of Virology and Biomedicine, University of Veterinary Medicine, A-1210 Vienna, Austria. christoph.metzner@vu-wien.ac.at
authors.forename: Christoph
authors.initials: C
authors.lastname: Metzner
authors.forename: Brian
authors.initials: B
authors.lastname: Salmons
authors.forename: Walter H
authors.initials: WH
authors.lastname: Gunzburg
authors.forename: Manfred
authors.initials: M
authors.lastname: Gemeiner
authors.forename: Ingrid
authors.initials: I
authors.lastname: Miller
authors.forename: Bernd
authors.initials: B
authors.lastname: Gesslbauer
authors.forename: Andreas
authors.initials: A
authors.lastname: Kungl
authors.forename: John A
authors.initials: JA
authors.lastname: Dangerfield
mesh_terms: D000818:Animals; D002460:Cell Line; D015180:Electrophoresis, Gel, Two-Dimensional; D005786:Gene Expression Regulation; D008156:Luciferases / Q000378:metabolism; D008324:Mammary Tumor Virus, Mouse / Q000472:pathogenicity*; D013058:Mass Spectrometry / Q000379:methods; D051379:Mice; D011506:Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018089:Superantigens / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D011506:Proteins; D018089:Superantigens; D014764:Viral Proteins; D008156:Luciferases