Project description:HTLV-1 is an onco-retrovirus that infects human T cells and causes poor prognosis leukaemia/lymphoma, ATL. The viral RNA binding protein, Rex, intervenes in host cell regulation of gene expression, splicing and translation mechanisms to promote viral particle replication, but the detailed mechanism of its function has not been elucidated. In the present study, we stably overexpressed HTLV-1 Rex in the human T-cell-derived cell line, CEM, and investigated effect of Rex on splicing patterns in CEM cells by exon microarray analysis.
Project description:HTLV-1 is an onco-retrovirus that infects human T cells and causes poor prognosis leukaemia/lymphoma, ATL. The viral RNA binding protein, Rex, intervenes in host cell regulation of gene expression, splicing and translation mechanisms to promote viral particle replication, but the detailed mechanism of its function has not been elucidated. In the present study, we stably overexpressed HTLV-1 Rex in the human T-cell-derived cell line, CEM, and investigated effect of Rex on gene expression profiles in CEM cells by gene expression microarray analysis.
Project description:The hijacking of CRM1 export is an important step of the retroviral replication cycle. Here, we investigated the consequences of this hijacking for the host. During HTLV-1 infection, we identified the formation of a complex composed of REX, CRM1 and the RNA helicase UPF1, leading to the nuclear retention of UPF1. We further showed how this mislocalization leads to the inhibition of the nonsense mediated mRNA decay (NMD), known to have an antiviral function. Corroborating these results, we described a similar process with Rev, the functional homolog of Rex from HIV-1. Unexpectedly, we also found that, for HTLV-1, this process is coupled with the specific loading of UPF1 onto vRNA, independently of NMD. In this latter context, UPF1 positively regulates several steps of the viral replication cycle, from the nuclear export of vRNA to the production of mature viral particles.
Project description:A conditional and isogenic system for APOBEC3B (A3B) induction in T-REx-293 cells. Cells were engineered to express doxycycline-inducible A3B-eGFP or eGFP constructs and subjected to 10 rounds of A3B-eGFP exposure causing 80-90% cell death. Control pools (eGFP) were subjected to parallel rounds of non-toxic eGFP exposure, and dilutions were done each round to mimic A3B-eGFP induced population fluctuations. DNA was extracted and subjected to SNP analyses using the Human OmniExpress-24v1-0 BeadChip (Illumina, San Diego, CA). Genotyping was performed using the humanomniexpress_24v1-0_a cluster file.
Project description:The objective of this comparison was to identify the impact of rex deletion on the transcriptome of Streptococcus pneumoniae D39. This comparison showed that the transcriptional regulator, Rex acts as a transcriptional repressor of a number of genes/operons (adhB1, fba, hemH, rex, gapN, nirC, pncB, gap, adhE, and adhB2) involved in niacin uptake and biosynthesis in the presence of NADH. In this study, we investigated the transcriptomic response of Streptococcus pneumoniae D39 to NADH. Transcriptome comparison of the D39 wild-type grown in chemically-defined medium (CDM) with 0 mg/ml NADH to 0.5 mg/ml NADH revealed elevated expression of various genes/operons (adhB1, fba, hemH, rex, gapN, nirC, pncB, gap, adhE, and adhB2) involved in the transport and biosynthesis of niacin. Microarray results were further confirmed by β-galactosidase assays. Promoter-lacZ fusions assays and microarray studies showed that the transcriptional regulator, Rex acts as a transcriptional repressor of a number of genes/operons (adhB1, fba, hemH, rex, gapN, nirC, pncB, gap, adhE, and adhB2) involved in niacin uptake and biosynthesis in the presence of NADH. The putative operator site of Rex in the promoter regions of Rex-regulated genes is predicted and confirmed by promoter mutational experiments.