Nuclear import of prototype foamy virus transactivator Bel1 is mediated by KPNA1, KPNA6 and KPNA7 Retraction in /10.3892/ijmm.2017.2860

Duan,Jihui; Tang,Zhiqin; Mu,Hong; Zhang,Guojun

doi:10.3892/ijmm.2016.2635

Nuclear import of prototype foamy virus transactivator Bel1 is mediated by KPNA1, KPNA6 and KPNA7

Retraction in: /10.3892/ijmm.2017.2860

Authors:
- Jihui Duan
- Zhiqin Tang
- Hong Mu
- Guojun Zhang
View Affiliations

Affiliations: Clinical Laboratory, Tianjin First Center Hospital, Tianjin 300192, P.R. China
Published online on: June 9, 2016 https://doi.org/10.3892/ijmm.2016.2635
Pages: 399-406
Copyright: © Duan et al. This is an open access article distributed under the terms of Creative Commons Attribution License.

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Abstract

Bel1, a transactivator of the prototype foamy virus (PFV), plays pivotal roles in the replication of PFV. Previous studies have demonstrated that Bel1 bears a nuclear localization signal (NLS); however, its amino acid sequence remains unclear and the corresponding adaptor importins have not yet been identified. In this study, we inserted various fragments of Bel1 into an EGFP-GST fusion protein and investigated their subcellular localization by fluorescence microscopy. We found that the 215PRQKRPR221 fragment, which accords with the consensus sequence K(K/R)X(K/R) of the monopartite NLS, directed the nuclear translocation of Bel1. Point mutation experiments revealed that K218, R219 and R221 were essential for the nuclear localization of Bel1. The results of GST pull-down assay revealed that the Bel1 peptide 215-221, which bears the NLS, interacted with the nucleocytoplasmic transport receptors, karyopherin alpha 1 (importin alpha 5) (KPNA1), karyopherin alpha 6 (importin alpha 7) (KPNA6) and karyopherin alpha 7 (importin alpha 8) (KPNA7). Finally, in vitro nuclear import assays demonstrated that KPNA1, KPNA6 or KPNA7, along with other necessary nuclear factors, caused Bel1 to localize to the nucleus. Thus, the findings of our study indicate that KPNA1, KPNA6 and KPNA7 are involved in Bel1 nuclear distribution.

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1	Broussard SR, Comuzzie AG, Leighton KL, Leland MM, Whitehead EM and Allan JS: Characterization of new simian foamy viruses from African nonhuman primates. Virology. 237:349–359. 1997. View Article : Google Scholar : PubMed/NCBI
2	Hatama S, Otake K, Omoto S, Murase Y, Ikemoto A, Mochizuki M, Takahashi E, Okuyama H and Fujii Y: Isolation and sequencing of infectious clones of feline foamy virus and a human/feline foamy virus Env chimera. J Gen Virol. 82:2999–3004. 2001. View Article : Google Scholar : PubMed/NCBI
3	Herchenröder O, Renne R, Loncar D, Cobb EK, Murthy KK, Schneider J, Mergia A and Luciw PA: Isolation, cloning, and sequencing of simian foamy viruses from chimpanzees (SFVcpz): high homology to human foamy virus (HFV). Virology. 201:187–199. 1994. View Article : Google Scholar : PubMed/NCBI
4	Materniak M, Bicka L and Kuźmak J: Isolation and partial characterization of bovine foamy virus from Polish cattle. Pol J Vet Sci. 9:207–211. 2006.
5	Tobaly-Tapiero J, Bittoun P, Neves M, Guillemin MC, Lecellier CH, Puvion-Dutilleul F, Gicquel B, Zientara S, Giron ML, de Thé H, et al: Isolation and characterization of an equine foamy virus. J Virol. 74:4064–4073. 2000. View Article : Google Scholar
6	Löchelt M, Zentgraf H and Flügel RM: Construction of an infectious DNA clone of the full-length human spumaretrovirus genome and mutagenesis of the bel 1 gene. Virology. 184:43–54. 1991. View Article : Google Scholar : PubMed/NCBI
7	He F, Blair WS, Fukushima J and Cullen BR: The human foamy virus Bel-1 transcription factor is a sequence-specific DNA binding protein. J Virol. 70:3902–3908. 1996.PubMed/NCBI
8	Kang Y, Blair WS and Cullen BR: Identification and functional characterization of a high-affinity Bel-1 DNA binding site located in the human foamy virus internal promoter. J Virol. 72:504–511. 1998.PubMed/NCBI
9	Löchelt M, Flügel RM and Aboud M: The human foamy virus internal promoter directs the expression of the functional Bel 1 transactivator and Bet protein early after infection. J Virol. 68:638–645. 1994.PubMed/NCBI
10	Chang J, Lee KJ, Jang KL, Lee EK, Baek GH and Sung YC: Human foamy virus Bel1 transactivator contains a bipartite nuclear localization determinant which is sensitive to protein context and triple multimerization domains. J Virol. 69:801–808. 1995.PubMed/NCBI
11	Venkatesh LK, Theodorakis PA and Chinnadurai G: Distinct cis-acting regions in U3 regulate trans-activation of the human spumaretrovirus long terminal repeat by the viral bel1 gene product. Nucleic Acids Res. 19:3661–3666. 1991. View Article : Google Scholar : PubMed/NCBI
12	Flügel RM: Spumaviruses: a group of complex retroviruses. J Acquir Immune Defic Syndr. 4:739–750. 1991.PubMed/NCBI
13	He F, Sun JD, Garrett ED and Cullen BR: Functional organization of the Bel-1 trans activator of human foamy virus. J Virol. 67:1896–1904. 1993.PubMed/NCBI
14	Venkatesh LK and Chinnadurai G: The carboxy-terminal transcription enhancement region of the human spumaretrovirus transactivator contains discrete determinants of the activator function. J Virol. 67:3868–3876. 1993.PubMed/NCBI
15	Venkatesh LK, Yang C, Theodorakis PA and Chinnadurai G: Functional dissection of the human spumaretrovirus transactivator identifies distinct classes of dominant-negative mutants. J Virol. 67:161–169. 1993.PubMed/NCBI
16	Lee CW, Chang J, Lee KJ and Sung YC: The Bel1 protein of human foamy virus contains one positive and two negative control regions which regulate a distinct activation domain of 30 amino acids. J Virol. 68:2708–2719. 1994.PubMed/NCBI
17	Ma Q, Tan J, Cui X, Luo D, Yu M, Liang C and Qiao W: Residues R(199)H(200) of prototype foamy virus transactivator Bel1 contribute to its binding with LTR and IP promoters but not its nuclear localization. Virology. 449:215–223. 2014. View Article : Google Scholar : PubMed/NCBI
18	Görlich D, Prehn S, Laskey RA and Hartmann E: Isolation of a protein that is essential for the first step of nuclear protein import. Cell. 79:767–778. 1994. View Article : Google Scholar : PubMed/NCBI
19	van der Watt PJ, Stowell CL and Leaner VD: The nuclear import receptor Kpnβ1 and its potential as an anticancer therapeutic target. Crit Rev Eukaryot Gene Expr. 23:1–10. 2013. View Article : Google Scholar
20	Flores K and Seger R: Stimulated nuclear import by β-like importins. F1000Prime Rep. 5:412013. View Article : Google Scholar
21	Zehorai E and Seger R: Beta-like importins mediate the nuclear translocation of mitogen-activated protein kinases. Mol Cell Biol. 34:259–270. 2014. View Article : Google Scholar :
22	Goldfarb DS, Corbett AH, Mason DA, Harreman MT and Adam SA: Importin alpha: a multipurpose nuclear-transport receptor. Trends Cell Biol. 14:505–514. 2004. View Article : Google Scholar : PubMed/NCBI
23	Cimica V, Chen HC, Iyer JK and Reich NC: Dynamics of the STAT3 transcription factor: nuclear import dependent on Ran and importin-β1. PLoS One. 6:e201882011. View Article : Google Scholar
24	Pumroy RA and Cingolani G: Diversification of importin-α isoforms in cellular trafficking and disease states. Biochem J. 466:13–28. 2015. View Article : Google Scholar : PubMed/NCBI
25	Mattaj IW and Englmeier L: Nucleocytoplasmic transport: the soluble phase. Annu Rev Biochem. 67:265–306. 1998. View Article : Google Scholar : PubMed/NCBI
26	Kelley JB, Talley AM, Spencer A, Gioeli D and Paschal BM: Karyopherin alpha7 (KPNA7), a divergent member of the importin alpha family of nuclear import receptors. BMC Cell Biol. 11:632010. View Article : Google Scholar : PubMed/NCBI
27	Köhler M, Speck C, Christiansen M, Bischoff FR, Prehn S, Haller H, Görlich D and Hartmann E: Evidence for distinct substrate specificities of importin alpha family members in nuclear protein import. Mol Cell Biol. 19:7782–7791. 1999. View Article : Google Scholar : PubMed/NCBI
28	Life RB, Lee EG, Eastman SW and Linial ML: Mutations in the amino terminus of foamy virus Gag disrupt morphology and infectivity but do not target assembly. J Virol. 82:6109–6119. 2008. View Article : Google Scholar : PubMed/NCBI
29	Cassany A and Gerace L: Reconstitution of nuclear import in permeabilized cells. Methods Mol Biol. 464:181–205. 2009. View Article : Google Scholar
30	Adam SA, Marr RS and Gerace L: Nuclear protein import in permeabilized mammalian cells requires soluble cytoplasmic factors. J Cell Biol. 111:807–816. 1990. View Article : Google Scholar : PubMed/NCBI
31	McLane LM and Corbett AH: Nuclear localization signals and human disease. IUBMB Life. 61:697–706. 2009. View Article : Google Scholar : PubMed/NCBI
32	Marfori M, Lonhienne TG, Forwood JK and Kobe B: Structural basis of high-affinity nuclear localization signal interactions with importin-α. Traffic. 13:532–548. 2012. View Article : Google Scholar : PubMed/NCBI
33	Jans DA, Xiao CY and Lam MH: Nuclear targeting signal recognition: a key control point in nuclear transport? BioEssays. 22:532–544. 2000. View Article : Google Scholar : PubMed/NCBI
34	Stewart M: Molecular mechanism of the nuclear protein import cycle. Nat Rev Mol Cell Biol. 8:195–208. 2007. View Article : Google Scholar : PubMed/NCBI
35	Marfori M, Mynott A, Ellis JJ, Mehdi AM, Saunders NF, Curmi PM, Forwood JK, Bodén M and Kobe B: Molecular basis for specificity of nuclear import and prediction of nuclear localization. Biochim Biophys Acta. 1813:1562–1577. 2011. View Article : Google Scholar
36	Fontes MR, Teh T and Kobe B: Structural basis of recognition of monopartite and bipartite nuclear localization sequences by mammalian importin-alpha. J Mol Biol. 297:1183–1194. 2000. View Article : Google Scholar : PubMed/NCBI
37	Keller A, Partin KM, Löchelt M, Bannert H, Flügel RM and Cullen BR: Characterization of the transcriptional trans activator of human foamy retrovirus. J Virol. 65:2589–2594. 1991.PubMed/NCBI
38	Meertens L, Chevalier S, Weil R, Gessain A and Mahieux R: A 10-amino acid domain within human T-cell leukemia virus type 1 and type 2 tax protein sequences is responsible for their divergent subcellular distribution. J Biol Chem. 279:43307–43320. 2004. View Article : Google Scholar : PubMed/NCBI
39	Gu L, Tsuji T, Jarboui MA, Yeo GP, Sheehy N, Hall WW and Gautier VW: Intermolecular masking of the HIV-1 Rev NLS by the cellular protein HIC: novel insights into the regulation of Rev nuclear import. Retrovirology. 8:172011. View Article : Google Scholar : PubMed/NCBI
40	Korlimarla A, Bhandary L, Prabhu JS, Shankar H, Sankaranarayanan H, Kumar P, Remacle J, Natarajan D and Sridhar TS: Identification of a non-canonical nuclear localization signal (NLS) in BRCA1 that could mediate nuclear localization of splice variants lacking the classical NLS. Cell Mol Biol Lett. 18:284–296. 2013. View Article : Google Scholar : PubMed/NCBI
41	Soniat M and Chook YM: Nuclear localization signals for four distinct karyopherin-β nuclear import systems. Biochem J. 468:353–362. 2015. View Article : Google Scholar : PubMed/NCBI
42	Lange A, Mills RE, Lange CJ, Stewart M, Devine SE and Corbett AH: Classical nuclear localization signals: Definition, function, and interaction with importin alpha. J Biol Chem. 282:5101–5105. 2007. View Article : Google Scholar
43	Larkin MA, Blackshields G, Brown NP, Chenna R, McGettigan PA, McWilliam H, Valentin F, Wallace IM, Wilm A, Lopez R, et al: Clustal W and Clustal X version 2.0. Bioinformatics. 23:2947–2948. 2007. View Article : Google Scholar : PubMed/NCBI
44	Henikoff S and Henikoff JG: Amino acid substitution matrices from protein blocks. Proc Natl Acad Sci USA. 89:10915–10919. 1992. View Article : Google Scholar : PubMed/NCBI
45	Köhler M, Ansieau S, Prehn S, Leutz A, Haller H and Hartmann E: Cloning of two novel human importin-alpha subunits and analysis of the expression pattern of the importin-alpha protein family. FEBS Lett. 417:104–108. 1997. View Article : Google Scholar : PubMed/NCBI