Human immunodeficiency virus type 1 Vpr-binding protein VprBP, a WD40 protein associated with the DDB1-CUL4 E3 ubiquitin ligase, is essential for DNA replication and embryonic development.

Journal Article (Journal Article)

Damaged DNA binding protein 1, DDB1, bridges an estimated 90 or more WD40 repeats (DDB1-binding WD40, or DWD proteins) to the CUL4-ROC1 catalytic core to constitute a potentially large number of E3 ligase complexes. Among these DWD proteins is the human immunodeficiency virus type 1 (HIV-1) Vpr-binding protein VprBP, whose cellular function has yet to be characterized but has recently been found to mediate Vpr-induced G(2) cell cycle arrest. We demonstrate here that VprBP binds stoichiometrically with DDB1 through its WD40 domain and through DDB1 to CUL4A, subunits of the COP9/signalsome, and DDA1. The steady-state level of VprBP remains constant during interphase and decreases during mitosis. VprBP binds to chromatin in a DDB1-independent and cell cycle-dependent manner, increasing from early S through G(2) before decreasing to undetectable levels in mitotic and G(1) cells. Silencing VprBP reduced the rate of DNA replication, blocked cells from progressing through the S phase, and inhibited proliferation. VprBP ablation in mice results in early embryonic lethality. Conditional deletion of the VprBP gene in mouse embryonic fibroblasts results in severely defective progression through S phase and subsequent apoptosis. Our studies identify a previously unknown function of VprBP in S-phase progression and suggest the possibility that HIV-1 Vpr may divert an ongoing chromosomal replication activity to facilitate viral replication.

Full Text

Duke Authors

Cited Authors

  • McCall, CM; Miliani de Marval, PL; Chastain, PD; Jackson, SC; He, YJ; Kotake, Y; Cook, JG; Xiong, Y

Published Date

  • September 2008

Published In

Volume / Issue

  • 28 / 18

Start / End Page

  • 5621 - 5633

PubMed ID

  • 18606781

Pubmed Central ID

  • PMC2546929

Electronic International Standard Serial Number (EISSN)

  • 1098-5549

Digital Object Identifier (DOI)

  • 10.1128/MCB.00232-08


  • eng

Conference Location

  • United States