title: Subcellular localization of the bovine leukemia virus R3 and G4 accessory proteins.
abstract: Bovine leukemia virus (BLV) is a complex retrovirus that belongs to the Deltaretrovirus genus, which also includes Human T-cell leukemia virus type 1 (HTLV-1). Both viruses contain an X region coding for at least four proteins: Tax and Rex, which are involved in transcriptional and posttranscriptional regulation, respectively, and the accessory proteins R3 and G4 (for BLV) and p12(I), p13(II), and p30(II) (for HTLV-1). The present study was aimed at characterizing the subcellular localization of BLV R3 and G4. The results of immunofluorescence experiments on transfected HeLa Tat cells demonstrated that R3 is located in the nucleus and in cellular membranes, as previously reported for HTLV-1 p12(I). In contrast, G4, like p13(II), is localized both in the nucleus and in mitochondria. In addition, we have shown that G4 harbors a mitochondrial targeting signal consisting of a hydrophobic region and an amphipathic alpha-helix. Thus, despite a lack of significant primary sequence homology, R3 and p12(I) and G4 and p13(II) exhibit similar targeting properties, suggesting possible overlap in their functional properties.
authors.affiliation: Faculty of Agronomy, Gembloux, University of Liège, Liège, Belgium.
authors.forename: Laurent
authors.initials: L
authors.lastname: Lefèbvre
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Ciminale
authors.forename: Alain
authors.initials: A
authors.lastname: Vanderplasschen
authors.forename: Donna
authors.initials: D
authors.lastname: D'Agostino
authors.forename: Arsène
authors.initials: A
authors.lastname: Burny
authors.forename: Luc
authors.initials: L
authors.lastname: Willems
authors.forename: Richard
authors.initials: R
authors.lastname: Kettmann
mesh_terms: D000818:Animals; D002417:Cattle; D015696:Gene Products, tat / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D001909:Leukemia Virus, Bovine / Q000378:metabolism*; D008928:Mitochondria; D009856:Oncogene Proteins, Viral / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012191:Retroviridae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013347:Subcellular Fractions / Q000378:metabolism*
chemical_list: D015696:Gene Products, tat; D009856:Oncogene Proteins, Viral; D012191:Retroviridae Proteins; C446341:g4 protein, Bovine leukemia virus