ABSTRACT
The major obstacle to cure infections with human immunodeficiency virus (HIV-1) is integrated proviral genomes, which are not eliminated by antiretroviral therapies (ART). Treatment approaches with latency-reversing agents (LRAs) aim at inducing provirus expression to tag latently-infected cells for clearance through viral cytopathic effects or cytotoxic T cell (CTL) responses. However, the currently tested LRAs reveal evident drawbacks as gene expression is globally induced and viral outgrowth is insecure. Here, we present transcription activator-like effector (TALE) proteins as potent tools to activate HIV-1 specifically. The large variety of circulating HIV-1 strains and, accordingly, integrated proviruses was addressed by the programmable DNA-specificity of TALEs. Using customized engineered TALEs, a substantial transcription activation and viral outgrowth was achieved with cells obtained from different HIV-1 patients. Our data suggest that TALEs may be useful tools in future strategies aimed at removing HIV-1 reservoirs.
Subject(s)
HIV Infections/metabolism , HIV-1/physiology , Transcription Factors/metabolism , Virus Activation , Gene Expression Regulation, Viral , HIV Infections/genetics , HIV Infections/virology , HIV-1/genetics , Humans , Multigene Family , Species Specificity , Transcription Factors/genetics , Viral Proteins/genetics , Viral Proteins/metabolism , Virus LatencyABSTRACT
Here we show that designed transcription activator-like effectors (TALEs) that bind to defined areas of the interferon beta promoter are capable to induce IFN-beta expression and signaling in human cells. Importantly, TALE-mediated IFN-beta signaling occurs independently of pathogen pattern recognition but effectively prohibits viral RNA replication as demonstrated with a hepatitis C virus replicon. TALEs were thus indicated to be valuable tools in various applications addressing, for example, virus-host interactions.
Subject(s)
Interferon-beta/biosynthesis , Transcription Factors/genetics , Transcriptional Activation , Base Sequence , Cell Line, Tumor , Hepacivirus/physiology , Humans , Immunity, Innate , Interferon-beta/genetics , Promoter Regions, Genetic , Protein Binding , Protein Engineering , RNA, Viral/genetics , Recombinant Proteins/biosynthesis , Recombinant Proteins/genetics , Signal Transduction , Transcription Factors/biosynthesis , Virus ReplicationABSTRACT
We here identify protein kinase D1 (PKD1) as a major regulator of anchorage-dependent and -independent growth of cancer cells controlled via the transcription factor Snail1. Using FRET, we demonstrate that PKD1, but not PKD2, efficiently interacts with Snail1 in nuclei. PKD1 phosphorylates Snail1 at Ser-11. There was no change in the nucleocytoplasmic distribution of Snail1 using wild type Snail1 and Ser-11 phosphosite mutants in different tumor cells. Regardless of its phosphorylation status or following co-expression of constitutively active PKD, Snail1 was predominantly localized to cell nuclei. We also identify a novel mechanism of PKD1-mediated regulation of Snail1 transcriptional activity in tumor cells. The interaction of the co-repressors histone deacetylases 1 and 2 as well as lysyl oxidase-like protein 3 with Snail1 was impaired when Snail1 was not phosphorylated at Ser-11, which led to reduced Snail1-associated histone deacetylase activity. Additionally, lysyl oxidase-like protein 3 expression was up-regulated by ectopic PKD1 expression, implying a synergistic regulation of Snail1-driven transcription. Ectopic expression of PKD1 also up-regulated proliferation markers such as Cyclin D1 and Ajuba. Accordingly, Snail1 and its phosphorylation at Ser-11 were required and sufficient to control PKD1-mediated anchorage-independent growth and anchorage-dependent proliferation of different tumor cells. In conclusion, our data show that PKD1 is crucial to support growth of tumor cells via Snail1.
