Region-specific distribution of human immunodeficiency virus type 1 long terminal repeats containing specific configurations of CCAAT/enhancer-binding protein site II in brains derived from demented and nondemented patients

2004 ◽  
Vol 10 (1) ◽  
pp. 7-14 ◽  
Author(s):  
Tricia Burdo ◽  
Suzanne Gartner ◽  
David Mauger ◽  
Brian Wigdahl
2008 ◽  
Vol 28 (18) ◽  
pp. 5621-5633 ◽  
Author(s):  
Chad M. McCall ◽  
Paula L. Miliani de Marval ◽  
Paul D. Chastain ◽  
Sarah C. Jackson ◽  
Yizhou J. He ◽  
...  

ABSTRACT 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 G2 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 G2 before decreasing to undetectable levels in mitotic and G1 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.


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