Phenotypic and Genotypic Comparisons of Human T-Cell Leukemia Virus Type 1 Reverse Transcriptases from Infected T-Cell Lines and Patient Samples

Mitchell, Michael S.; Bodine, Ellen T.; Hill, S. A.; Princler, Gerald L.; Lloyd, Patricia A.; Mitsuya, Hiroaki; Matsuoka, Masao; Derse, David

doi:10.1128/jvi.02660-06

Cited by 19 publications

(19 citation statements)

References 61 publications

(58 reference statements)

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“…Interestingly, our data showing the effects of PCOANs and TFV on RTs from different HTLV-1-infected cell lines emphasize the fact that, although HTLV-1, unlike other retroviruses, is characterized by low genetic variability, sensitivity of HTLV-1 RT of different origins to the inhibitory activity of an NRTI compound could vary greatly. However, a recent study on the pol genes and deduced amino acid sequences from primary isolates and proviruses from cell lines revealed some genetic differences in the RT-encoding regions (29). Among these differences, the HUT102 cell line, established from an HTLV-1-infected individual, presented two threonine residue variations at positions 197 and 429, in place of the consensus sequence of MT-2, although viruses from these cell lines are classified as belonging to the same cosmopolitan transcontinental subgroup A.…”

Section: Discussionmentioning

confidence: 99%

Effect of Phosphonated Carbocyclic 2′-Oxa-3′-Aza-Nucleoside on Human T-Cell Leukemia Virus Type 1 Infection In Vitro

Balestrieri¹,

Matteucci

Ascolani

et al. 2008

Antimicrob Agents Chemother

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The human T-cell leukemia/lymphoma virus type 1 (HTLV-1) is an oncogenic retrovirus endemic in certain areas of the world including Japan and North and South America, where about 5% of the estimated 20 million HTLV-1-infected people develop HTLV-1-associated diseases (10,11,43), such as adult T-cell leukemia (ATL), human myelopathy/tropical spastic paraparesis (/TSP), or other minor inflammatory diseases. A number of studies have shown that HTLV-1 infects different types of cells (e.g., lymphocytes, monocytes, and fibroblasts) but preferentially T lymphocytes with a CD4 ϩ phenotype, which become immortalized following infection (26). In HTLV-1 infection viremia is essentially a "cytoviremia," since the virus is cell associated. In fact, cell-free virions are rarely infectious, and spreading of the virus in vivo does not require the extracellular release of viral particles. The spread of the virus within an individual host is most commonly recognized as being through the mitotic pathway, in which cell divisions and clonal expansion of infected cells ensure a constant level of viral load. However, recently it has been highlighted that the HTLV-1 viral load in vivo is also sustained by cell-tocell contact, involving intercellular viral spread. In particular, this "horizontal" spread allows the transfer of HTLV-1 infectious viral particles across the cell-cell junction by the generation of "virological synapses" between infected and uninfected cells (19,21). Transmission of HTLV-1 via cell-to-cell contact involves both integrin (3) and cytoskeleton proteins and participation of Env protein-cell receptor interactions (37). Either way, efficient transmission of HTLV-1 to noninfected cells implies reverse transcriptase (RT) dependency.In recent years, a number of strategies for therapeutic intervention have been pursued in the treatment of ATL or TSP, based on conventional chemotherapy or innovative approaches. However, until now, limited advances have been achieved in improving the therapy for HTLV-1-associated diseases. Therefore, symptomatic HTLV-1-infected patients still have inadequate treatment options with poor prognoses. Among the novel approaches for treating HTLV-1-related diseases, the use of topoisomerase 1 or 2 inhibitors in a pilot phase II study in refractory ATL did not provide satisfactory results (41). Similarly, treatments with the nucleoside analogue 2Ј deoxycoformycin (39) or inhibitors of AMP synthesis resulted in a limited response in ATL patients (42). Interestingly, studies based on a different strategy of chemotherapeutic intervention showed that ATL patients transiently responded to combined therapy with the nucleoside reverse transcriptase inhibitor (NRTI) azidothymidine (AZT) and interferon (IFN) (15) and that AZT treatment was beneficial to TSP patients (33), giving more encouraging results. In addition, a transient response to therapy with the NRTI lamivudine alone (38) or in combination with AZT (25) has been reported for human myelopathy/TSP. Moreover, IFN-␣ has been shown to have some ...

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Section: Discussionmentioning

confidence: 99%

Effect of Phosphonated Carbocyclic 2′-Oxa-3′-Aza-Nucleoside on Human T-Cell Leukemia Virus Type 1 Infection In Vitro

Balestrieri¹,

Matteucci

Ascolani

et al. 2008

Antimicrob Agents Chemother

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“…To initiate the HIV-1-based assay, cells were cotransfected with 0.6 g of helper plasmid pCMV⌬8.2R (Addgene accession number 12263), which expresses all HIV-1 proteins except Env; 0.15 g of the pCMV-VSV-G plasmid (Addgene accession number 8454), which expresses protein G from vesicular stomatitis virus (VSV-G); and 0.9 g of reporter plasmid. To initiate the HTLV-1-based assay, 293T cells were cotransfected with 0.6 g of the pCMV HT1-M plasmid, which expresses the full-length HTLV-1 genome (14,15), and 0.9 g of a reporter plasmid. The culture medium was replaced at 16 h posttransfection.…”

Section: Methodsmentioning

confidence: 99%

Improvement of HIV-1 and Human T Cell Lymphotropic Virus Type 1 Replication-Dependent Vectors via Optimization of Reporter Gene Reconstitution and Modification with Intronic Short Hairpin RNA

Shunaeva

Potashnikova

Пичугин

et al. 2015

J Virol

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Cell-to-cell transmission is an efficient mechanism to disseminate human immunodeficiency virus type 1 (HIV-1) and human T cell lymphotropic virus type 1 (HTLV-1). However, it has been challenging to quantify the level of cell-to-cell transmission because the virus-producing cells cannot be easily distinguished from infected target cells. We have previously described replication-dependent vectors that can quantify infection events in cocultured cells. These vectors contain an antisense-oriented promoter and reporter gene interrupted by a sense-oriented intron from the human gamma-globin gene. This strategy prevents expression of the reporter gene in the transfected cells but permits its expression in target cells after infection. However, the gamma-globin intron is not efficiently removed by splicing in the aforementioned vectors, thereby reducing the level of reporter gene expression after transduction into target cells. Here, we used two approaches to improve the replication-dependent vectors. First, we improved the splicing events that remove the gamma-globin intron by optimizing the intron insertion site within the reporter gene. Second, we improved the packaging of the spliced RNA without the gamma-globin intron by targeting the introncontaining RNA via microRNA 30 (miR30)-based short hairpin RNAs. Using two optimized fluorescent reporter vectors and flow cytometry, we determined that multiply HIV-1-infected cells were generated at a higher frequency in coculture than in cellfree infection; furthermore, this increase was dependent upon viruses bearing HIV-1 Env. Compared with previously described vectors, these improved vectors can quantify the infection in lymphocytes and in primary cells with a higher sensitivity and allow the detection and quantitation of multiply infected cells, providing better tools to study retroviral cell-mediated infection. IMPORTANCEThe human-pathogenic retroviruses HTLV-1 and HIV-1 can be transmitted more efficiently in vivo via direct contact of infected cells with healthy target cells than through cell-free virion-mediated infection. Despite its importance, cell-to-cell transmission has been difficult to quantify because the previously infected cells and the newly infected cells are mixed together in the same culture. In the current study, we generated vectors that are significantly improved over the previously described replication-dependent vectors. As a result, these improved vectors can efficiently detect and quantify cell-to-cell transmission or new infection events in cells in mixed culture. These luciferase-or fluorescence protein-based reporter vectors can be used to quantify and study HIV-1 or HTLV-1 cell-mediated infection in a simple one-step transfection/infection assay.

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“…QT6 quail cells were transfected with an infectious molecular clone of HTLV-1 (pX1MT-M) (30) in the presence or absence of the hA3G expression plasmid. Twenty-four hours posttransfection, HTLV-1-producing QT6 cells were treated with 200 g/ml of mitomycin C at 37°C for 30 min, washed well, and then cocultivated 1:1 with fresh QT6 cells (13).…”

Section: Methodsmentioning

confidence: 99%

APOBEC3G Generates Nonsense Mutations in Human T-Cell Leukemia Virus Type 1 Proviral Genomes In Vivo

Fan

Nosaka

et al. 2010

J Virol

Self Cite

106

118

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Human T-cell leukemia virus type 1 (HTLV-1) induces cell proliferation after infection, leading to efficient transmission by cell-to-cell contact. After a long latent period, a fraction of carriers develop adult T-cell leukemia (ATL). Genetic changes in the tax gene in ATL cells were reported in about 10% of ATL cases. To determine genetic changes that may occur throughout the provirus, we determined the entire sequence of the HTLV-1 provirus in 60 ATL cases. Abortive genetic changes, including deletions, insertions, and nonsense mutations, were frequent in all viral genes except the HBZ gene, which is transcribed from the minus strand of the virus. G-to-A base substitutions were the most frequent mutations in ATL cells. The sequence context of G-to-A mutations was in accordance with the preferred target sequence of human APOBEC3G (hA3G). The target sequences of hA3G were less frequent in the plus strand of the HBZ coding region than in other coding regions of the HTLV-1 provirus. Nonsense mutations in viral genes including tax were also observed in proviruses from asymptomatic carriers, indicating that these mutations were generated during reverse transcription and prior to oncogenesis. The fact that hA3G targets the minus strand during reverse transcription explains why the HBZ gene is not susceptible to such nonsense mutations. HTLV-1-infected cells likely take advantage of hA3G to escape from the host immune system by losing expression of viral proteins.

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Phenotypic and Genotypic Comparisons of Human T-Cell Leukemia Virus Type 1 Reverse Transcriptases from Infected T-Cell Lines and Patient Samples

Cited by 19 publications

References 61 publications

Effect of Phosphonated Carbocyclic 2′-Oxa-3′-Aza-Nucleoside on Human T-Cell Leukemia Virus Type 1 Infection In Vitro

Effect of Phosphonated Carbocyclic 2′-Oxa-3′-Aza-Nucleoside on Human T-Cell Leukemia Virus Type 1 Infection In Vitro

Improvement of HIV-1 and Human T Cell Lymphotropic Virus Type 1 Replication-Dependent Vectors via Optimization of Reporter Gene Reconstitution and Modification with Intronic Short Hairpin RNA

APOBEC3G Generates Nonsense Mutations in Human T-Cell Leukemia Virus Type 1 Proviral Genomes In Vivo

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