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At least 127 records · Page 7Linked to original sources
PubMed2002

Use of both 16S rRNA and engineered functional genes with real-time PCR to quantify an engineered, PCB-degrading Rhodococcus in soil.

A real-time PCR (RTm-PCR) assay using fluorescently labeled oligonucleotides (TaqMan probes) was used to detect and quantify the recombinant Rhodococcus sp. strain RHA1(fcb) in soil. One primer and probe set targeted a hypervariable region of the 16S rRNA gene unique to strain RHA1(fcb) and its phylogenetic relatives, and the other set targeted the recombinant 4-chlorobenzoate (4-CBA) degradation operon (fcb) and was strain-specific. The method had a 6-log dynamic range of detection (10(2)-10(7) cells ml(-1)) for both probes when DNA from pure cultures was used. Although the method was less sensitive in soil, the estimated number of cells in soil by real-time PCR corresponded to the measured number of RHA1(fcb) cells determined by colony-forming units.

Biodegradation, Environmental↗
PubMed2002

Genes and engineered cells as drugs for type I and type II diabetes mellitus therapy and prevention.

Despite the manageability of diabetes mellitus, complications associated with the disorder necessitate novel approaches to prevent immune-mediated impairment and destruction in type 1 diabetes, as well as the pancreatic insufficiency and peripheral resistance to insulin in type 2 diabetes. Islet transplantation is evolving into a clinical reality to treat type 1 diabetics and novel uses of gene engineering technology promise to result in tolerance to auto-, allo- and xenoantigens as well as microenvironment-specific immunosuppression. Through the use of a variety of gene delivery vehides, an increasing number of studies demonstrate the feasibility of shielding islet transplants and surrogate beta cells from immune rejection by the local secretion of immunosuppressive soluble molecules and anti-apoptotic factors. Although the achievements of gene and cell therapy in type 2 diabetes mellitus are less clear, seminal studies demonstrate the relevance of this approach to the treatment and perhaps prevention of the underlying causes of the disease, including obesity and insulin resistance. In this review, we attempt to illustrate pivotal studies demonstrating the suitability of genes and cells as drugs in type 1 and type 2 diabetes mellitus, and also provide some other targets that may be suitable for clinical utility.

Animals↗
PubMed1999

Mammalian spermatogenesis investigated by genetic engineering.

Genes involved in mammal spermatogenesis can now be identified through mutants created by genetic engineering. Information has been obtained on male meiosis, but also on the factors regulating the proliferation, maintenance and differentiation of male germ cells. Its has also increased our knowledge of the germ cell phenotype emerging from an altered germ cell genotype. This review is focused on data from genes expressed in male germ cells and on the question of how germ cells and Sertoli cells cope with the molecular lesions induced. The conservation of a wild-type phenotype of male germ cells in mutant mice is discussed, and how the mouse genetic background can lead to different germ cell phenotypes for a given gene mutation.

Animals↗
PubMed2005

Tuning genetic control through promoter engineering.

Gene function is typically evaluated by sampling the continuum of gene expression at only a few discrete points corresponding to gene knockout or overexpression. We argue that this characterization is incomplete and present a library of engineered promoters of varying strengths obtained through mutagenesis of a constitutive promoter. A multifaceted characterization of the library, especially at the single-cell level to ensure homogeneity, permitted quantitative assessment correlating the effect of gene expression levels to improved growth and product formation phenotypes in Escherichia coli. Integration of these promoters into the chromosome can allow for a quantitative accurate assessment of genetic control. To this end, we used the characterized library of promoters to assess the impact of phosphoenolpyruvate carboxylase levels on growth yield and deoxy-xylulose-P synthase levels on lycopene production. The multifaceted characterization of promoter strength enabled identification of optimal expression levels for ppc and dxs, which maximized the desired phenotype. Additionally, in a strain preengineered to produce lycopene, the response to deoxy-xylulose-P synthase levels was linear at all levels tested, indicative of a rate-limiting step, unlike the parental strain, which exhibited an optimum expression level, illustrating that optimal gene expression levels are variable and dependent on the genetic background of the strain. This promoter library concept is illustrated as being generalizable to eukaryotic organisms (Saccharomyces cerevisiae) and thus constitutes an integral platform for functional genomics, synthetic biology, and metabolic engineering endeavors.

Escherichia coli↗
PubMedDate not supplied

[Tissue engineering and gene therapy of the musculoskeletal system with muscle cells].

AIM: Muscle-based somatic gene therapy is a novel way to alleviate a biochemical deficiency. METHOD: Muscle-derived cells are very promising in the field of gene therapy and tissue engineering. First, most muscle tissue is accessible by injection. Second, muscle tissue consists of multinucleated, postmitotic myofibers, which enable a long-term expression of the transduced gene. Third, muscle tissue can be biopsied easily. It is available in abundance and the biopsy does not compromise the health and function of the patient. Finally, muscle tissue is highly vascularized, which makes systemic delivery feasible. RESULTS: Muscle-derived cells can promote muscle healing and bone healing. Implanted cells maintain a long-term transgene expression of therapeutic proteins. Isolated, muscle-derived stem cells can differentiate in osteoblasts. CONCLUSION: Based on these characteristics, we present four possible applications: inherited muscular diseases, muscle injury, bone healing, and intraarticular disorders.

Gene Expression↗
PubMed2006

Introduction of an initiator element in the mouse thymidylate synthase promoter alters S phase regulation but has no effect on promoter bidirectionality.

The promoter of the mouse thymidylate synthase (TS) gene lacks a TATAA box and an initiator element, is bidirectional and initiates transcription at multiple start sites across broad initiation windows upstream and downstream of the 30 nt essential promoter region. The TS promoter also plays an essential role in the post-transcription regulation of TS gene expression during the G(1)-S phase transition. The goal of this study was to determine if the addition of a TATAA box or an initiator element would have a significant effect on start-site pattern, promoter bidirectionality and S phase regulation of the TS gene. A TATAA box and/or an initiator element were inserted downstream of the TS essential promoter region, and the modified promoters were used to drive expression of indicator genes. The engineered genes were transfected into cultured mammalian cells, and the effects of the mutations were determined. Addition of the TATAA box and especially the initiator element had a significant effect on the transcription start site pattern, indicating that the elements were functional. Unexpectedly, addition of one or both of these elements had no effect on promoter bidirectionality. However, inclusion of the initiator element led to a significant reduction in S phase regulation of TS mRNA levels, indicating that changes in promoter architecture can perturb normal S phase regulation of TS gene expression.

Animals↗
PubMed2005

[The construction of pSecTag2/B vector modified by osteoprotegerin].

PURPOSE: In order to treat periodontitis by using tissue engineering and gene engineering technology, we constructed mammalian secreted expression pSecTag2/B-OPG vector, the cDNA sequence encoding osteoprotegerin(OPG) obtaining from 293 cell. METHODS: The primers were designed based on the human OPG cDNA sequence. Total mRNA was isolated from 293 cells and RT-PCR was performed .The fragment was recombined into pSecTag2/B vector and sequenced by automatic sequence analyzer. RESULTS: The sequences of OPG cDNA from 293 cell by RT-PCR were completely identical to the sequences provided by GenBank [gi:33878056]. After polymerase chain reaction and the recombinant plasmid digesting with Hind III,EcoR I and BamH I,1% agarose electrophoresis showed several fragments, which were consistent with predicted size. CONCLUSION: From cultured 293 cells the cDNA has been cloned and pSecTag2/B-OPG vector has been constructed successfully. Supported by Research Fund (No.03043304) from Anhui Provincial Natural Science Foundation.

Animals↗
PubMed2004

Regenerative medicine in andrology: Tissue engineering and gene therapy as potential treatment options for penile deformations and erectile dysfunction.

Tissue engineering and gene therapy are currently investigated in animal studies for reconstructing penile tissue or treating erectile dysfunction. This review aims to examine these experimental efforts from the last years and tries to give a brief introduction to the basic methodology of these new techniques from the field of regenerative medicine.

Andrology↗
PubMed2006

[Regenerative medicine in andrology: tissue engineering and gene therapy as potential treatment options for penile deformations and erectile dysfunction].

Tissue engineering and gene therapy are currently investigated in animal studies for reconstructing penile tissue or treating erectile dysfunction. This review aims to ecamine these experimental efforts from the last years and tries to give a brief introduction to the basic methodology of these new techniques from the field of regenerative medicine.

Animals↗
PubMed2003

The engineering of gene regulatory networks.

The rapid accumulation of genetic information and advancement of experimental techniques have opened a new frontier in biomedical engineering. With the availability of well-characterized components from natural gene networks, the stage has been set for the engineering of artificial gene regulatory networks with sophisticated computational and functional capabilities. In these efforts, the ability to construct, analyze, and interpret qualitative and quantitative models is becoming increasingly important. In this review, we consider the current state of gene network engineering from a combined experimental and modeling perspective. We discuss how networks with increased complexity are being constructed from simple modular components and how quantitative deterministic and stochastic modeling of these modules may provide the foundation for accurate in silico representations of gene regulatory network function in vivo.

Animals↗
PubMed2004

Immunotherapy of cancer using systemically delivered gene-modified human T lymphocytes.

The use of gene-engineered T cells expressing chimeric single-chain (scFv) receptors capable of codelivering CD28 costimulation and T cell receptor zeta chain (TCR-zeta) activation signals has emerged as a promising treatment regimen for cancer. Using retroviral transduction, primary human T lymphocytes were gene-engineered to express the scFv-CD28-zeta chimeric receptor reactive with the ErbB2 tumor-associated antigen. We demonstrated the ability of these gene-engineered human T cells to produce high levels of cytokines, proliferate vigorously, and mediate lysis of ErbB2(+) tumors in an antigen-specific manner. Furthermore, such gene-engineered human T cells significantly delayed the growth of two distinct subcutaneous ErbB2(+) human tumors in irradiated nonobese diabetic-severe combined immunodeficient (NOD-SCID) mice after systemic administration. These preclinical studies are an important proof of principle that human T cells may be genetically redirected to tumors in cancer patients.

Animals↗
PubMed1999

[Cloning and sequencing of variable region gene of heavy chain of monoclonal antibody against SA I/II of Streptococcus mutans].

OBJECTIVE: To clone and sequence a immunoglobulin variable region of heavy chain (VH) from a mouse hybridoma 2B12F6, which produce monoclonal antibody against SA I/II of Streptococcus mutans. METHODS: The immunoglobulin variable region gene of heavy chain of 2B12F6 was amplified and cloned into pUC18 by using PCR technique and gene engineering technique, and then the gene sequence was analyzed by Sanger's method. RESULTS: The VH gene segment was 360 base pairs in length and coded 118 amino acids, and the homology of framework of VH gene and mouse VH gene published was 70%, which accorded with the feature of mouse VH gene. CONCLUSION: The VH gene gained from 2B12F6 could provide the possibility of construction of gene engineering antibody against SA I/II of Streptococcus mutans.

Amino Acid Sequence↗
PubMed2003

Current knowledge of gene flow in plants: implications for transgene flow.

Plant evolutionary biologists' view of gene flow and hybridization has undergone a revolution. Twenty-five years ago, both were considered rare and largely inconsequential. Now gene flow and hybridization are known to be idiosyncratic, varying with the specific populations involved. Gene flow typically occurs at evolutionarily significant rates and at significant distances. Spontaneous hybridization occasionally has important applied consequences, such as stimulating the evolution of more aggressive invasives and increasing the extinction risk for rare species. The same problems have occurred for spontaneous hybridization between crops and their wild relatives. These new data have implications for transgenic crops: (i) for most crops, gene flow can act to introduce engineered genes into wild populations; (ii) depending on the specific engineered gene(s) and populations involved, gene flow may have the same negative impacts as those observed for traditionally improved crops; (iii) gene flow's idiosyncratic nature may frustrate management and monitoring attempts; and (iv) intercrop transgene flow, although rarely discussed, is equally worthy of study.

Biological Evolution↗
PubMed2003

Inhibition of cartilage degradation: a combined tissue engineering and gene therapy approach.

OBJECTIVE: To determine if tissue-engineered cartilage can be protected from cytokine-induced degradation using a gene therapy approach. METHODS: Chemical and pantropic retroviral gene transfer methodologies were compared for their ability to introduce a luciferase reporter gene into adult bovine cartilage chondrocytes grown in monolayer. Pantropic retrovirus was then used to transduce these cells with human tissue inhibitor of metalloproteinases 1 (TIMP-1), and the stability of expression in monolayer or pellet culture was monitored for 6 weeks. Untransduced and TIMP-1-transduced cells were also used to tissue engineer 3-dimensional cartilage constructs that were then challenged with interleukin-1 (IL-1) for 4 weeks. Conditioned media and residual cartilage were collected for analysis of matrix components, including type II collagen and proteoglycans, and for TIMP-1 production and matrix metalloproteinase (MMP) activity. RESULTS: Chemical transfection of adult bovine chondrocytes gave rise to short-lived reporter expression that was virtually undetectable after 4 weeks of culture. In contrast, pantropic retroviral transduction gave rise to stable expression that persisted at a high level for at least 6 weeks. Pantropic transduction of the cells with TIMP-1 gave rise to similar long-term expression, both in monolayer and pellet cultures. TIMP-1-transduced tissue-engineered cartilage also retained TIMP-1 expression for an additional 4 weeks of culture in the presence of IL-1. Compared with control samples, TIMP-1-transgenic cartilage resisted the catabolic effects of IL-1, with MMP activity reduced to basal levels and a decreased loss of type II collagen. CONCLUSION: Pantropic retroviral transduction permits long-term expression of potentially therapeutic transgenes in adult tissue-engineered cartilage. While TIMP-1 transduction could be used to prevent collagen breakdown, alternative transgenes may be necessary to protect cartilage proteoglycans.

Animals↗
PubMed2003

Re-engineering plant gene targeting.

The genome sequence of Arabidopsis is complete and the genomes of plants representing legumes (Medicago truncatula) and grasses (rice) will soon follow. The rate at which new genes have been discovered has far outstripped the pace at which their function is determined. The greatest hurdle that plant biologists face in assigning gene function and in crop improvement is the lack of efficient and robust technologies to generate gene replacements or targeted gene knockouts. Many of the factors underlying these events remain to be elucidated. This review addresses the current status of plant gene targeting and what is known about the associated plant DNA repair mechanisms.

DNA, Plant↗
PubMed2006

Tissue engineering by modulated gene delivery.

Tissue engineering is a newly emerging biomedical form to create a local environment which enables cells to promote the proliferation and differentiation for regeneration induction. The cell-induced regeneration of tissues and organs is achieved by making use of the tissue engineering technology or methodology. Several genetic approaches with virus and non-viral vectors or genetically engineered cells have been attempted to enhance tissue regeneration. The basic idea is to promote the cell proliferation and differentiation as well as the secretion of biological signal molecules for tissue regeneration from cells by gene transfection. For successful gene transfection and expression, it is important to develop drug delivery system (DDS) which allows a therapeutic gene to be delivered specifically to the target cell at an appropriate timing for a certain time period. This paper overviews the recent development of gene-modified tissue engineering, briefly explaining delivery technologies necessary to modulate the efficiency of gene transfection.

Animals↗
PubMedDate not supplied

The impact of mammalian gene regulation concepts on functional genomic research, metabolic engineering, and advanced gene therapies.

Regulation of heterologous gene expression is of prime importance for a wide variety of basic and applied biological research areas including functional genomics, tissue engineering, gene therapy, and biopharmaceutical manufacturing. Initial gene regulation strategies employed endogenous responsive elements, which resulted in pleiotropic interference of transgene expression with host regulatory networks. Current regulation systems are binary and consist of chimeric transactivators and responsive target promoters of heterologous bacterial or insect origin, or they contain artificially designed components. Regulation of generic systems is based on binding of a transactivator to its cognate promoter, which is modulated by specific molecules such as antibiotics or hormones and brings the transactivation domain into contact with a minimal promoter, thereby inducing target gene expression. Binary gene regulation concepts have been significantly refined in recent years with a focus to improve their regulation performance and their compatibility with human-therapeutic use. In this review we present a detailed analysis of currently available mammalian gene regulation systems and document progress that has pioneered the use of such systems in various aspects of human therapy.

Animals↗