scholarly journals Construction and Characterization of a Human T-Cell Lymphotropic Virus Type 3 Infectious Molecular Clone

2008 ◽  
Vol 82 (13) ◽  
pp. 6747-6752 ◽  
Author(s):  
Sébastien Alain Chevalier ◽  
Nga Ling Ko ◽  
Sara Calattini ◽  
Adeline Mallet ◽  
Marie-Christine Prévost ◽  
...  

ABSTRACT We and others have uncovered the existence of human T-cell lymphotropic virus type 3 (HTLV-3). We have now generated an HTLV-3 proviral clone. We established that gag, env, pol, pro, and tax/rex as well as minus-strand mRNAs are present in cells transfected with the HTLV-3 clone. HTLV-3 p24 gag protein is detected in the cell culture supernatant. Transfection of 293T-long terminal repeat (LTR)-green fluorescent protein (GFP) cells with the HTLV-3 clone promotes formation of syncytia, a hallmark of Env expression, together with the appearance of fluorescent cells, demonstrating that Tax is expressed. Viral particles are visible by electron microscopy. These particles are infectious, as demonstrated by infection experiments with purified virions.

2007 ◽  
Vol 81 (12) ◽  
pp. 6276-6285 ◽  
Author(s):  
Sébastien Alain Chevalier ◽  
Marine Walic ◽  
Sara Calattini ◽  
Adeline Mallet ◽  
Marie-Christine Prévost ◽  
...  

ABSTRACT Together with their simian T-cell lymphotropic virus (STLV) equivalent, human T-cell lymphotropic virus type 1 (HTLV-1), HTLV-2, and HTLV-3 form the primate T-cell lymphotropic virus (PTLV) group. Over the years, understanding the biology and pathogenesis of HTLV-1 and HTLV-2 has been widely improved by the creation of molecular clones. In contrast, so far, PTLV-3 experimental studies have been restricted to the overexpression of the tax gene using reporter assays. We have therefore decided to construct an STLV-3 molecular clone. We generated a full-length STLV-3 proviral clone (8,891 bp) by PCR amplification of overlapping fragments. This STLV-3 molecular clone was then transfected into 293T cells. Reverse transcriptase PCR experiments followed by sequence analysis of the amplified products allowed us to establish that both gag and tax/rex mRNAs were transcribed. Western blotting further demonstrated the presence of the STLV-3 p24 gag protein in the cell culture supernatant from transfected cells. Transient transfection of 293T cells and of 293T-long terminal repeat-green fluorescent protein cells with the STLV-3 clone promoted syncytium formation, a hallmark of PTLV Env expression, as well as the appearance of fluorescent cells, also demonstrating that the Tax3 protein was expressed. Virus particles were visible by electron microscopy. These particles are infectious, as demonstrated by our cell-free-infection experiments with purified virions. All together, our data demonstrate that the STLV-3 molecular clone is functional and infectious. This clone will give us a unique opportunity to study in vitro the different pX transcripts and the putative presence of antisense transcripts and to evaluate the PTLV-3 pathogenicity in vivo.


2006 ◽  
Vol 22 (10) ◽  
pp. 953-959 ◽  
Author(s):  
Simone Kashima ◽  
Luiz Carlos Alcantara ◽  
Osvaldo Massaiti Takayanagui ◽  
Marco Aurelio Valtas Cunha ◽  
Bernardo Galvão Castro ◽  
...  

2011 ◽  
Vol 5 (4) ◽  
pp. e1038 ◽  
Author(s):  
Ana Carolina P. Vicente ◽  
Eduardo Samo Gudo ◽  
Alena Mayo Iñiguez ◽  
Koko Otsuki ◽  
Nilesh Bhatt ◽  
...  

2012 ◽  
Vol 93 (12) ◽  
pp. 2646-2651 ◽  
Author(s):  
Nga Ling Ko ◽  
Emmanuel Birlouez ◽  
Simon Wain-Hobson ◽  
Renaud Mahieux ◽  
Jean-Pierre Vartanian

RNA editing mediated by adenosine deaminases acting on RNA (ADARs) converts adenosine (A) to inosine (I) residues in dsRNA templates. While ADAR-1-mediated editing was essentially described for RNA viruses, the present work addresses the issue for two δ-retroviruses, human T-cell leukemia virus type 2 and simian T-cell leukemia virus type 3 (HTLV-2 and STLV-3). We examined whether ADAR-1 could edit HTLV-2 and STLV-3 virus genomes in cell culture and in vivo. Using a highly sensitive PCR-based method, referred to as 3DI-PCR, we showed that ADAR-1 could hypermutate adenosine residues in HTLV-2. STLV-3 hypermutation was obtained without using 3DI-PCR, suggesting a higher mutation frequency for this virus. Detailed analysis of the dinucleotide editing context showed preferences for 5′ ArA and 5′ UrA. In conclusion, the present observations demonstrate that ADAR-1 massively edits HTLV-2 and STLV-3 retroviruses in vitro, but probably remains a rare phenomenon in vivo.


Virology ◽  
1995 ◽  
Vol 209 (2) ◽  
pp. 445-456 ◽  
Author(s):  
Vincenzo Ciminale ◽  
Donna M. D'Agostino ◽  
Lorenza Zotti ◽  
Genoveffa Franchini ◽  
Barbara K. Felber ◽  
...  

PLoS ONE ◽  
2014 ◽  
Vol 9 (3) ◽  
pp. e93374 ◽  
Author(s):  
Rodrigo Pessôa ◽  
Jaqueline Tomoko Watanabe ◽  
Youko Nukui ◽  
Juliana Pereira ◽  
Jorge Kasseb ◽  
...  

2009 ◽  
Vol 83 (10) ◽  
pp. 5244-5255 ◽  
Author(s):  
Kathryn S. Jones ◽  
Ying K. Huang ◽  
Sébastien A. Chevalier ◽  
Philippe V. Afonso ◽  
Cari Petrow-Sadowski ◽  
...  

ABSTRACT Little is known about the transmission or tropism of the newly discovered human retrovirus, human T-cell lymphotropic virus type 3 (HTLV-3). Here, we examine the entry requirements of HTLV-3 using independently expressed Env proteins. We observed that HTLV-3 surface glycoprotein (SU) binds efficiently to both activated CD4+ and CD8+ T cells. This contrasts with both HTLV-1 SU, which primarily binds to activated CD4+ T cells, and HTLV-2 SU, which primarily binds to activated CD8+ T cells. Binding studies with heparan sulfate proteoglycans (HSPGs) and neuropilin-1 (NRP-1), two molecules important for HTLV-1 entry, revealed that these molecules also enhance HTLV-3 SU binding. However, unlike HTLV-1 SU, HTLV-3 SU can bind efficiently in the absence of both HSPGs and NRP-1. Studies of entry performed with HTLV-3 Env-pseudotyped viruses together with SU binding studies revealed that, for HTLV-1, glucose transporter 1 (GLUT-1) functions at a postbinding step during HTLV-3 Env-mediated entry. Further studies revealed that HTLV-3 SU binds efficiently to naïve CD4+ T cells, which do not bind either HTLV-1 or HTLV-2 SU and do not express detectable levels of HSPGs, NRP-1, and GLUT-1. These results indicate that the complex of receptor molecules used by HTLV-3 to bind to primary T lymphocytes differs from that of both HTLV-1 and HTLV-2.


2006 ◽  
Vol 80 (19) ◽  
pp. 9876-9888 ◽  
Author(s):  
Sara Calattini ◽  
Sébastien Alain Chevalier ◽  
Renan Duprez ◽  
Philippe Afonso ◽  
Alain Froment ◽  
...  

ABSTRACT We and others have recently uncovered the existence of human T-cell lymphotropic virus type 3 (HTLV-3), the third member of the HTLV family. We have now sequenced the full-length HTLV-3Pyl43 provirus. As expected, HTLV-3Pyl43 contains open reading frames corresponding to the gag, pol, env, tax, and rex genes. Interestingly, its long terminal repeat (LTR) includes only two Tax-responsive elements, as is the case for type 3 simian T-cell lymphotropic viruses (STLV-3). Phylogenetic analyses reveal that HTLV-3Pyl43 is closely related to central African STLV-3. Unexpectedly, the proximal pX region of HTLV-3Pyl43 lacks 366 bp compared to its STLV-3 counterpart. Because of this deletion, the previously described RorfII sequence is lacking. At the amino acid level, Tax3Pyl43 displays strong similarities with HTLV-1 Tax, including the sequence of a PDZ class I binding motif. In transient-transfection assays, Tax3Pyl43 activates the transcriptions from HTLV-3, HTLV-1, and HTLV-2 LTRs. Mutational analysis indicates that two functional domains (M22 and M47) important for transactivation through the CREB/ATF or NF-κB pathway are similar but not identical in Tax1 and Tax3Pyl43. We also show that Tax3Pyl43 transactivates the human interleukin-8 and Bcl-XL promoters through the induction of the NF-κB pathway. On the other hand, Tax3Pyl43 represses the transcriptional activity of the p53 tumor suppressor protein as well as the c-Myb promoter. Altogether, these results demonstrate that although HTLV-3 and HTLV-1 have only 60% identity, Tax3Pyl43 is functionally closely related to the transforming protein Tax1 and suggest that HTLV-3, like HTLV-1, might be pathogenic in vivo.


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