In Vitro Interaction between Human Immunodeficiency Virus Type 1 Rev Protein and Splicing Factor ASF/SF2-associated Protein, p32

Abstract

Continuous replication of human immunodeficiency virus type 1 requires the expression of the regulatory protein Rev, which binds to the Rev response element (RRE) and up-regulates the cytoplasmic appearance of singly spliced and unspliced mRNA species. It has been demonstrated that the murine protein YL2 interacts with Rev in vivo and modulates the activity of Rev (Luo, Y., Yu, H., and Peterlin, B. M. (1994) J. Virol. 68, 3850-3856). Here we show that the YL2 human homologue, the p32 protein, which co-purifies with alternative splicing factor ASF/SF2, interacts directly with the basic domain of Rev in vitro and that the Rev-p32 complex is resistant to high concentrations of salt or nonionic detergent. Protein footprinting data suggest that Rev interacts specifically with amino acids within the 196-208 region of p32. An analysis of the ternary complex, formed among p32, Rev, and RRE RNA, shows that Rev can bridge the association of p32 and RRE. Furthermore, we demonstrate that exogenously added p32 specifically relieves the inhibition of splicing in vitro exerted by the basic domain of Rev. Our data are consistent with a model in which p32 functions as a link between Rev and the cellular splicing apparatus.

Adenovirus core protein V interacts with p32--a protein which is associated with both the mitochondria and the nucleus.

“…It is interesting that many of these proteins are involved in splicing and transcriptional regulation. Thus HIV Rev appears to be responsible for switching the viral transcription expression pattern from multiply-spliced viral RNAs to singly spliced mRNAs in the cytoplasm (Tange et al, 1996). It is also relevant to note that an earlier publication (Somasundaran et al, 1994) had shown that HIV RNA D. A.…”

p32 Is a Novel Target for Viral Protein ICP34.5 of Herpes Simplex Virus Type 1 and Facilitates Viral Nuclear Egress

“…Human p32 interacts with various cellular and pathogen proteins such as pre-mRNA splicing factor in the nucleus (41), BH3-only protein harakiri in the mitochondria (42), HIV Tat and Rev (43,44), human cytomegalovirus (CMV) pUL97 at the nuclear membrane (45), and hepatitis C virus core protein on the cell surface (46). Besides, by yeast two-hybrid assay, p32 was identified to interact with ectopically expressed LBR in vitro (47,48).…”

Drosophila TAP/p32 is a core histone chaperone that cooperates with NAP-1, NLP, and nucleophosmin in sperm chromatin remodeling during fertilization

“…TAP/p32 was originally isolated as a protein that binds and inhibits an essential cellular splicing factor, ASF/SF2 (Krainer et al 1990;PetersenMahrt et al 1999). TAP/p32 also inhibits splicing of HIV transcripts (Berro et al 2006); its interaction with the HIV Rev protein promotes export of unspliced HIV RNA (Tange et al 1996). TAP/p32 physically interacts with plasma complement component C1q and inhibits its hemolytic activity (Ghebrehiwet et al 1994).…”