title: Human immunodeficiency virus type 1 Vpr interacts with HHR23A, a cellular protein implicated in nucleotide excision DNA repair.
abstract: The human immunodeficiency virus type 1 (HIV-1) vpr gene is an evolutionarily conserved gene among the primate lentiviruses HIV-1, HIV-2, and simian immunodeficiency viruses. One of the unique functions attributed to the vpr gene product is the arrest of cells in the G2 phase of the cell cycle. Here we demonstrate that Vpr interacts physically with HHR23A, one member of an evolutionarily conserved gene family involved in nucleotide excision repair. Interaction of Vpr with HHR23A was initially identified through a yeast two-hybrid screen and was confirmed by the demonstration of direct binding between bacterially expressed recombinant and transiently expressed or chemically synthesized protein products. Visualization of HHR23A and Vpr by indirect immunofluorescence and confocal microscopy indicates that the two proteins colocalize at or about the nuclear membrane. We also map the Vpr-binding domain in HHR23A to a C-terminal 45-amino-acid region of the protein previously shown to have homology to members of the ubiquitination pathway. Overexpression of HHR23A and a truncated derivative which includes the Vpr-binding domain results in a partial alleviation of the G2 arrest induced by Vpr, suggesting that the interaction between Vpr and HHR23A is critical for cell cycle arrest induced by Vpr. These results provide further support for the hypothesis that Vpr interferes with the normal function of a protein or proteins involved in the DNA repair process and, thus, in the transmission of signals that allow cells to transit from the G2 to the M phase of the cell cycle.
authors.affiliation: Department of Microbiology and Immunology, UCLA School of Medicine, Los Angeles, California 90095-1678, USA.
authors.forename: E S
authors.initials: ES
authors.lastname: Withers-Ward
authors.forename: J B
authors.initials: JB
authors.lastname: Jowett
authors.forename: S A
authors.initials: SA
authors.lastname: Stewart
authors.forename: Y M
authors.initials: YM
authors.lastname: Xie
authors.forename: A
authors.initials: A
authors.lastname: Garfinkel
authors.forename: Y
authors.initials: Y
authors.lastname: Shibagaki
authors.forename: S A
authors.initials: SA
authors.lastname: Chow
authors.forename: N
authors.initials: N
authors.lastname: Shah
authors.forename: F
authors.initials: F
authors.lastname: Hanaoka
authors.forename: D G
authors.initials: DG
authors.lastname: Sawitz
authors.forename: R W
authors.initials: RW
authors.lastname: Armstrong
authors.forename: L M
authors.initials: LM
authors.lastname: Souza
authors.forename: I S
authors.initials: IS
authors.lastname: Chen
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002453:Cell Cycle; D004260:DNA Repair; D045643:DNA Repair Enzymes; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D016336:Gene Products, vpr / Q000235:genetics / Q000378:metabolism*; D005982:Glutathione Transferase; D015497:HIV-1 / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013347:Subcellular Fractions; D014162:Transfection; D054325:vpr Gene Products, Human Immunodeficiency Virus
chemical_list: D004268:DNA-Binding Proteins; D016336:Gene Products, vpr; D011993:Recombinant Fusion Proteins; D054325:vpr Gene Products, Human Immunodeficiency Virus; C086985:RAD23A protein, human; D005982:Glutathione Transferase; D045643:DNA Repair Enzymes