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Profiling of genes deregulated in CD4+ T cells expressing constitutively full-length or first-exon Tat protein of HIV-1

ABSTRACT: Background: The role of HIV-1 Tat protein in gene expression deregulation and functional biology of CD4+ T lymphocytes was analyzed, as well as the function of Tat second exon for the complete activity of this protein. Gene expression deregulation profiles of triplicate samples from Jurkat cells expressing intracellular full-length Tat (1-101aa) in comparison with a truncated form lacking the second exon (1-72aa) was evaluated by bioinformatics using whole human genome microarrays. Results: More than 1000 genes were deregulated in Jurkat Tat101 cells, whereas less than 300 genes were deregulated in Jurkat Tat72 cells (q-value<5%; fold change >2 or <-2). Ontological analysis indicated that several functions were impaired mainly in Jurkat Tat101 as cellular movement, growth and proliferation, cell-to-cell signaling, molecular transport, cell death, cell morphology, and T-cell activation. In accordance, biological and functional analyses proved that Tat101 intracellular expression induced changes in cell size and complexity, cytoskeletal rearrangements and chemotaxis impairment, higher resistance to apoptosis, decrease in the surface expression of adhesion molecules and receptors, and higher basal transcriptional activation. These alterations were attenuated or absent in Jurkat Tat72 cells. Furthermore, computational modeling showed that the absence of second exon severely reduced the C-terminus of Tat72 with notable decrease of positive charging. Conclusion: Full-length Tat intracellular expression induced dramatic structural changes and impaired essential functions in CD4+ T cells, whereas Tat72 was less aggressive. Consequently, although Tat first exon is transcriptionally autonomous, second exon should be indispensable for triggering HIV-1 pathogenic events induced by Tat protein. Keywords: Microarray Genome-wide expression analysis. Comparison of genetically modified cells

ORGANISM(S): Homo sapiens

PROVIDER: GSE20088 | GEO | 2010/01/29

SECONDARY ACCESSION(S): PRJNA124289

REPOSITORIES: GEO

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Project description:Our previous work demonstrated that HIV-1 infection progressively reduces TCR/CD3 expression due to a defect in CD3g gene transcripts. We further found that knocking down expression of the viral tat and/or nef genes was correlated with CD3g transcript and TCR/CD3 surface receptor levels on HIV-1 infected cells. This study was undertaken to investigate the direct effect of HIV-1 Tat expression on the TCR/CD3 machinery. Progressive downregulation from TCR/CD3hi to TCR/CD3lo to TCR/CD3â was observed on Tat expressing cells in a manner that emulated HIV-1 infection, with a lack of CD3g transcripts again responsible for the defect. When Tat cell cultures containing a mixture of TCR/CD3 surface densities were separated into TCR/CD3hi and TCR/CD3lo/â populations, they quickly reverted to a mixed CD3 phenotype. Thus, the progression TCR/CD3hi to TCR/CD3lo to TCR/CD3â is an active, reversible process with receptor levels fluctuating in response to intracellular dynamics. Examination of tat mutants found that the regions involved in Tat-mediated transactivation and TAR binding are required for TCR/CD3 downregulation while the lysine at position 28 and Tat exon 2 are dispensable. Global gene expression, assessed in association with TCR/CD3 downregulation in HIV-1 infected and Tat expressing cells, detected broad suppression of TCR/CD3 signaling, co-stimulation and negative regulatory genes along with target transcription factors, ligands and receptors. A significant subset of the genes altered in HIV-1 infected cells was specifically targeted by Tat in association with TCR/CD3 loss. Our finding that Tat negatively regulates many facets of the TCR/CD3 machinery has important implications for disease pathogenesis. We used microarrays to investigate changes in CD4+ T cell gene expression induced by expression of the HIV-1 Tat protein. Examine changes in gene expression in HIV-1 Tat transduced cells compared with cells transduced with an antisense Tat sequence used as a control.

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Profiling of genes deregulated in CD4+ T cells expressing constitutively full-length or first-exon Tat protein of HIV-1

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