ABSTRACT
Technologies for regulated expression of multiple transgenes in mammalian cells have gathered momentum for bioengineering, gene therapy, drug discovery, and gene-function analyses. Capitalizing on recently developed mammalian transgene modalities (QuoRex) derived from Streptomyces coelicolor, we have designed a flexible and highly compatible expression vector set that enables desired transgene/siRNA control in response to the nontoxic butyrolactone SCB1. The construction-kit-like expression portfolio includes (i) multicistronic (pTRIDENT), (ii) autoregulated, (iii) bidirectional (pBiRex), (iv) oncoretro- and lentiviral transduction, and (v) RNA polymerase II-based siRNA transcription-fine-tuning vectors for straightforward implementation of QuoRex-controlled (trans)gene modulation in mammalian cells.
Subject(s)
Gene Expression Regulation , Gene Transfer Techniques , Genetic Vectors/genetics , RNA, Small Interfering/genetics , Signal Transduction/physiology , Animals , CHO Cells , Cell Culture Techniques/methods , Cricetinae , RNA, Small Interfering/biosynthesisABSTRACT
Capitalizing on components evolved to metabolize ethanol in Aspergillus nidulans, we previously designed the first molecular gas-gene expression interface using gaseous acetaldehyde as the major inducer. This fungus-derived acetaldehyde-inducible gene regulation (AIR) system operated perfectly and enabled precise and reversible transgene expression dosing in a variety of mammalian cells. We now validate the use of mainstream cigarette smoke typically containing acetaldehyde at regulation-effective nontoxic concentrations as a noninvasive modality to adjust transgene transcription in mammalian cells and mice. Indeed, tobacco smoke-induced expression fine-tuning of AIR-driven transgenes was successful in mammalian cells. Even mice implanted with cells transgenic for AIR-controlled SEAP (human secreted alkaline phosphatase) production showed serum SEAP levels correlating with inhaled tobacco smoke doses. Tobacco smoke-controlled gene expression may foster clinical opportunities as well as advances in understanding smoke-related pathologies.
Subject(s)
Acetaldehyde/pharmacology , Gene Expression Regulation/drug effects , Gene Transfer Techniques , Nicotiana/chemistry , Recombinant Proteins/biosynthesis , Smoke , Transfection/methods , Transgenes/drug effects , Animals , CHO Cells , Cricetinae , Cricetulus , Gases/pharmacology , Mice , Phase TransitionABSTRACT
BACKGROUND: Recent advances in functional genomics, gene therapy, tissue engineering, drug discovery and biopharmaceuticals production have been fostered by precise small-molecule-mediated fine-tuning of desired transgenes. METHODS: Capitalizing on well-evolved quorum-sensing regulatory networks in Streptomyces coelicolor we have designed a mammalian regulation system inducible by the non-toxic butyrolactone SCB1. Fusion of the S. coelicolor SCB1 quorum-sensing receptor ScbR to the human Kox-1-derived transsilencing domain reconstituted a mammalian transsilencer (SCS) able to repress transcription from SCS-specific operator-containing promoters in a reverse SCB1-adjustable manner. RESULTS: This quorum-sensing-derived mammalian transgene control system (Q-ON) enabled precise SCB1-specific fine-tuning of (i) desired transgene transcription in a variety of mammalian/human cell lines and human primary cells, (ii) small interfering RNA-mediated posttranscriptional knockdown (siRNA) in mammalian cells, and (iii) dosing of a human glycoprotein in mice. CONCLUSIONS: As exemplified by Q-ON technology, bacterial quorum-sensing regulons may represent a near-infinite source for the design of mammalian gene control systems compatible with molecular interventions relevant to future gene therapy and tissue engineering scenarios.
Subject(s)
Genetic Engineering , Protein Biosynthesis/physiology , RNA, Small Interfering/physiology , Streptomyces/genetics , Transcription, Genetic/physiology , 4-Butyrolactone/analogs & derivatives , 4-Butyrolactone/pharmacology , Animals , Base Sequence , Cell Line , Gene Expression Regulation/drug effects , Humans , Mice , Molecular Sequence Data , Oligonucleotides , TransgenesABSTRACT
We describe the design and detailed characterization of a gas-inducible transgene control system functional in different mammalian cells, mice and prototype biopharmaceutical manufacturing. The acetaldehyde-inducible AlcR-P(alcA) transactivator-promoter interaction of the Aspergillus nidulans ethanol-catabolizing regulon was engineered for gas-adjustable transgene expression in mammalian cells. Fungal AlcR retained its transactivation characteristics in a variety of mammalian cell lines and reversibly adjusted transgene transcription from chimeric mammalian promoters (P(AIR)) containing P(alcA)-derived operators in a gaseous acetaldehyde-dependent manner. Mice implanted with microencapsulated cells engineered for acetaldehyde-inducible regulation (AIR) of the human glycoprotein secreted placental alkaline phosphatase showed adjustable serum phosphatase levels after exposure to different gaseous acetaldehyde concentrations. AIR-controlled interferon-beta production in transgenic CHO-K1-derived serum-free suspension cultures could be modulated by fine-tuning inflow and outflow of acetaldehyde-containing gas during standard bioreactor operation. AIR technology could serve as a tool for therapeutic transgene dosing as well as biopharmaceutical manufacturing.
Subject(s)
Acetaldehyde/pharmacology , Gene Expression Regulation/drug effects , Isoenzymes/biosynthesis , Isoenzymes/genetics , Protein Engineering/methods , Transgenes/drug effects , Alkaline Phosphatase , Animals , Cell Line , Cricetinae , Dose-Response Relationship, Drug , Female , GPI-Linked Proteins , Gases/pharmacology , Genetic Enhancement/methods , Humans , Mice , Recombinant Proteins/biosynthesisABSTRACT
Prokaryotic transcriptional regulatory elements have been adopted for controlled expression of cloned genes in mammalian cells and animals, the cornerstone for gene-function correlations, drug discovery, biopharmaceutical manufacturing as well as advanced gene therapy and tissue engineering. Many prokaryotes have evolved specific molecular communication systems known as quorum-sensing to coordinate population-wide responses to physiological and/or physicochemical signals. A generic bacterial quorum-sensing system is based on a diffusible signal molecule that prevents binding of a repressor to corresponding operator sites thus resulting in derepression of a target regulon. In Streptomyces, a family of butyrolactones and their corresponding receptor proteins, serve as quorum-sensing systems that control morphological development and antibiotic biosynthesis. Fusion of the Streptomyces coelicolor quorum-sensing receptor (ScbR) to a eukaryotic transactivation domain (VP16) created a mammalian transactivator (SCA) which binds and adjusts transcription from chimeric promoters containing an SCA-specific operator module (P(SPA)). Expression of erythropoietin or the human secreted alkaline phosphatase (SEAP) by this quorum-sensor-regulated gene expression system (QuoRex) could be fine-tuned by non-toxic butyrolactones in a variety of mammalian cells including human primary and mouse embryonic stem cells. Following intraperitoneal implantation of microencapsulated Chinese hamster ovary cells transgenic for QuoRex-controlled SEAP expression into mice, the serum levels of this model glycoprotein could be adjusted to desired concentrations using different butyrolactone dosing regimes.
