Genetic Vectors: DNA molecules capable of autonomous replication within a host cell and into which other DNA sequences can be inserted and thus amplified. Many are derived from PLASMIDS; BACTERIOPHAGES; or VIRUSES. They are used for transporting foreign genes into recipient cells. Genetic vectors possess a functional replicator site and contain GENETIC MARKERS to facilitate their selective recognition.Insect Vectors: Insects that transmit infective organisms from one host to another or from an inanimate reservoir to an animate host.Disease Vectors: Invertebrates or non-human vertebrates which transmit infective organisms from one host to another.Gene Transfer Techniques: The introduction of functional (usually cloned) GENES into cells. A variety of techniques and naturally occurring processes are used for the gene transfer such as cell hybridization, LIPOSOMES or microcell-mediated gene transfer, ELECTROPORATION, chromosome-mediated gene transfer, TRANSFECTION, and GENETIC TRANSDUCTION. Gene transfer may result in genetically transformed cells and individual organisms.Transduction, Genetic: The transfer of bacterial DNA by phages from an infected bacterium to another bacterium. This also refers to the transfer of genes into eukaryotic cells by viruses. This naturally occurring process is routinely employed as a GENE TRANSFER TECHNIQUE.Adenoviridae: A family of non-enveloped viruses infecting mammals (MASTADENOVIRUS) and birds (AVIADENOVIRUS) or both (ATADENOVIRUS). Infections may be asymptomatic or result in a variety of diseases.Dependovirus: A genus of the family PARVOVIRIDAE, subfamily PARVOVIRINAE, which are dependent on a coinfection with helper adenoviruses or herpesviruses for their efficient replication. The type species is Adeno-associated virus 2.Lentivirus: A genus of the family RETROVIRIDAE consisting of non-oncogenic retroviruses that produce multi-organ diseases characterized by long incubation periods and persistent infection. Lentiviruses are unique in that they contain open reading frames (ORFs) between the pol and env genes and in the 3' env region. Five serogroups are recognized, reflecting the mammalian hosts with which they are associated. HIV-1 is the type species.Arthropod Vectors: Arthropods, other than insects and arachnids, which transmit infective organisms from one host to another or from an inanimate reservoir to an animate host.Support Vector Machines: Learning algorithms which are a set of related supervised computer learning methods that analyze data and recognize patterns, and used for classification and regression analysis.Transgenes: Genes that are introduced into an organism using GENE TRANSFER TECHNIQUES.Anopheles: A genus of mosquitoes (CULICIDAE) that are known vectors of MALARIA.Retroviridae: Family of RNA viruses that infects birds and mammals and encodes the enzyme reverse transcriptase. The family contains seven genera: DELTARETROVIRUS; LENTIVIRUS; RETROVIRUSES TYPE B, MAMMALIAN; ALPHARETROVIRUS; GAMMARETROVIRUS; RETROVIRUSES TYPE D; and SPUMAVIRUS. A key feature of retrovirus biology is the synthesis of a DNA copy of the genome which is integrated into cellular DNA. After integration it is sometimes not expressed but maintained in a latent state (PROVIRUSES).Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Transfection: The uptake of naked or purified DNA by CELLS, usually meaning the process as it occurs in eukaryotic cells. It is analogous to bacterial transformation (TRANSFORMATION, BACTERIAL) and both are routinely employed in GENE TRANSFER TECHNIQUES.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Cloning, Molecular: The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.Gene Expression: The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Green Fluorescent Proteins: Protein analogs and derivatives of the Aequorea victoria green fluorescent protein that emit light (FLUORESCENCE) when excited with ULTRAVIOLET RAYS. They are used in REPORTER GENES in doing GENETIC TECHNIQUES. Numerous mutants have been made to emit other colors or be sensitive to pH.Genetic Engineering: Directed modification of the gene complement of a living organism by such techniques as altering the DNA, substituting genetic material by means of a virus, transplanting whole nuclei, transplanting cell hybrids, etc.Arachnid Vectors: Members of the class Arachnida, especially SPIDERS; SCORPIONS; MITES; and TICKS; which transmit infective organisms from one host to another or from an inanimate reservoir to an animate host.Helper Viruses: Viruses which enable defective viruses to replicate or to form a protein coat by complementing the missing gene function of the defective (satellite) virus. Helper and satellite may be of the same or different genus.Aedes: A genus of mosquitoes (CULICIDAE) frequently found in tropical and subtropical regions. YELLOW FEVER and DENGUE are two of the diseases that can be transmitted by species of this genus.Mosquito Control: The reduction or regulation of the population of mosquitoes through chemical, biological, or other means.Promoter Regions, Genetic: DNA sequences which are recognized (directly or indirectly) and bound by a DNA-dependent RNA polymerase during the initiation of transcription. Highly conserved sequences within the promoter include the Pribnow box in bacteria and the TATA BOX in eukaryotes.Adenovirus E1 Proteins: The very first viral gene products synthesized after cells are infected with adenovirus. The E1 region of the genome has been divided into two major transcriptional units, E1A and E1B, each expressing proteins of the same name (ADENOVIRUS E1A PROTEINS and ADENOVIRUS E1B PROTEINS).beta-Galactosidase: A group of enzymes that catalyzes the hydrolysis of terminal, non-reducing beta-D-galactose residues in beta-galactosides. Deficiency of beta-Galactosidase A1 may cause GANGLIOSIDOSIS, GM1.Insect Control: The reduction or regulation of the population of noxious, destructive, or dangerous insects through chemical, biological, or other means.Luminescent Proteins: Proteins which are involved in the phenomenon of light emission in living systems. Included are the "enzymatic" and "non-enzymatic" types of system with or without the presence of oxygen or co-factors.Culicidae: A family of the order DIPTERA that comprises the mosquitoes. The larval stages are aquatic, and the adults can be recognized by the characteristic WINGS, ANIMAL venation, the scales along the wing veins, and the long proboscis. Many species are of particular medical importance.Genes, Reporter: Genes whose expression is easily detectable and therefore used to study promoter activity at many positions in a target genome. In recombinant DNA technology, these genes may be attached to a promoter region of interest.Anopheles gambiae: A species of mosquito in the genus Anopheles and the principle vector of MALARIA in Africa.Culex: A genus of mosquitoes (CULICIDAE) commonly found in tropical regions. Species of this genus are vectors for ST. LOUIS ENCEPHALITIS as well as many other diseases of man and domestic and wild animals.Recombination, Genetic: Production of new arrangements of DNA by various mechanisms such as assortment and segregation, CROSSING OVER; GENE CONVERSION; GENETIC TRANSFORMATION; GENETIC CONJUGATION; GENETIC TRANSDUCTION; or mixed infection of viruses.Escherichia coli: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.Adenoviruses, Human: Species of the genus MASTADENOVIRUS, causing a wide range of diseases in humans. Infections are mostly asymptomatic, but can be associated with diseases of the respiratory, ocular, and gastrointestinal systems. Serotypes (named with Arabic numbers) have been grouped into species designated Human adenovirus A-F.Insecticides: Pesticides designed to control insects that are harmful to man. The insects may be directly harmful, as those acting as disease vectors, or indirectly harmful, as destroyers of crops, food products, or textile fabrics.Recombinant Fusion Proteins: Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.DNA, Recombinant: Biologically active DNA which has been formed by the in vitro joining of segments of DNA from different sources. It includes the recombination joint or edge of a heteroduplex region where two recombining DNA molecules are connected.Malaria: A protozoan disease caused in humans by four species of the PLASMODIUM genus: PLASMODIUM FALCIPARUM; PLASMODIUM VIVAX; PLASMODIUM OVALE; and PLASMODIUM MALARIAE; and transmitted by the bite of an infected female mosquito of the genus ANOPHELES. Malaria is endemic in parts of Asia, Africa, Central and South America, Oceania, and certain Caribbean islands. It is characterized by extreme exhaustion associated with paroxysms of high FEVER; SWEATING; shaking CHILLS; and ANEMIA. Malaria in ANIMALS is caused by other species of plasmodia.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Virus Integration: Insertion of viral DNA into host-cell DNA. This includes integration of phage DNA into bacterial DNA; (LYSOGENY); to form a PROPHAGE or integration of retroviral DNA into cellular DNA to form a PROVIRUS.Gene Targeting: The integration of exogenous DNA into the genome of an organism at sites where its expression can be suitably controlled. This integration occurs as a result of homologous recombination.Recombinant Proteins: Proteins prepared by recombinant DNA technology.Lac Operon: The genetic unit consisting of three structural genes, an operator and a regulatory gene. The regulatory gene controls the synthesis of the three structural genes: BETA-GALACTOSIDASE and beta-galactoside permease (involved with the metabolism of lactose), and beta-thiogalactoside acetyltransferase.Transformation, Genetic: Change brought about to an organisms genetic composition by unidirectional transfer (TRANSFECTION; TRANSDUCTION, GENETIC; CONJUGATION, GENETIC, etc.) and incorporation of foreign DNA into prokaryotic or eukaryotic cells by recombination of part or all of that DNA into the cell's genome.Virus Replication: The process of intracellular viral multiplication, consisting of the synthesis of PROTEINS; NUCLEIC ACIDS; and sometimes LIPIDS, and their assembly into a new infectious particle.Polymerase Chain Reaction: In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.Psychodidae: Small, hairy, moth-like flies which are of considerable public health importance as vectors of certain pathogenic organisms. Important disease-related genera are PHLEBOTOMUS, Lutzomyia, and Sergentomyia.Phlebotomus: A genus of PSYCHODIDAE which functions as the vector of a number of pathogenic organisms, including LEISHMANIA DONOVANI; LEISHMANIA TROPICA; Bartonella bacilliformis, and the Pappataci fever virus (SANDFLY FEVER NAPLES VIRUS).Triatoma: A genus of the subfamily TRIATOMINAE. Several species are vectors of TRYPANOSOMA CRUZI.Cells, Cultured: Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.Mice, Inbred BALB CCeratopogonidae: A family of biting midges, in the order DIPTERA. It includes the genus Culicoides which transmits filarial parasites pathogenic to man and other primates.Tumor Cells, Cultured: Cells grown in vitro from neoplastic tissue. If they can be established as a TUMOR CELL LINE, they can be propagated in cell culture indefinitely.Vaccines, Synthetic: Small synthetic peptides that mimic surface antigens of pathogens and are immunogenic, or vaccines manufactured with the aid of recombinant DNA techniques. The latter vaccines may also be whole viruses whose nucleic acids have been modified.DNA Primers: Short sequences (generally about 10 base pairs) of DNA that are complementary to sequences of messenger RNA and allow reverse transcriptases to start copying the adjacent sequences of mRNA. Primers are used extensively in genetic and molecular biology techniques.Insecticide Resistance: The development by insects of resistance to insecticides.Defective Viruses: Viruses which lack a complete genome so that they cannot completely replicate or cannot form a protein coat. Some are host-dependent defectives, meaning they can replicate only in cell systems which provide the particular genetic function which they lack. Others, called SATELLITE VIRUSES, are able to replicate only when their genetic defect is complemented by a helper virus.Mice, Inbred C57BLKanamycin Kinase: A class of enzymes that inactivate aminocyclitol-aminoglycoside antibiotics (AMINOGLYCOSIDES) by regiospecific PHOSPHORYLATION of the 3' and/or 5' hydroxyl.Gene Expression Regulation: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.Moloney murine leukemia virus: A strain of Murine leukemia virus (LEUKEMIA VIRUS, MURINE) arising during the propagation of S37 mouse sarcoma, and causing lymphoid leukemia in mice. It also infects rats and newborn hamsters. It is apparently transmitted to embryos in utero and to newborns through mother's milk.DNA: A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).Transcription, Genetic: The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.DNA, Viral: Deoxyribonucleic acid that makes up the genetic material of viruses.Capsid Proteins: Proteins that form the CAPSID of VIRUSES.Pyrethrins: The active insecticidal constituent of CHRYSANTHEMUM CINERARIIFOLIUM flowers. Pyrethrin I is the pyretholone ester of chrysanthemummonocarboxylic acid and pyrethrin II is the pyretholone ester of chrysanthemumdicarboxylic acid monomethyl ester.Mutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.Restriction Mapping: Use of restriction endonucleases to analyze and generate a physical map of genomes, genes, or other segments of DNA.Genes, Bacterial: The functional hereditary units of BACTERIA.Hemiptera: A large order of insects characterized by having the mouth parts adapted to piercing or sucking. It is comprised of four suborders: HETEROPTERA, Auchenorrhyncha, Sternorrhyncha, and Coleorrhyncha.RNA, Messenger: RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.Coxsackie and Adenovirus Receptor-Like Membrane Protein: An Ig superfamily transmembrane protein that localizes to junctional complexes that occur between ENDOTHELIAL CELLS and EPTHELIAL CELLS. The protein may play a role in cell-cell adhesion and is the primary site for the attachment of ADENOVIRUSES during infection.Adenoviruses, Simian: Species of the genus MASTADENOVIRUS associated with respiratory and enteric infections in primate hosts.HeLa Cells: The first continuously cultured human malignant CELL LINE, derived from the cervical carcinoma of Henrietta Lacks. These cells are used for VIRUS CULTIVATION and antitumor drug screening assays.Population Density: Number of individuals in a population relative to space.Artificial Intelligence: Theory and development of COMPUTER SYSTEMS which perform tasks that normally require human intelligence. Such tasks may include speech recognition, LEARNING; VISUAL PERCEPTION; MATHEMATICAL COMPUTING; reasoning, PROBLEM SOLVING, DECISION-MAKING, and translation of language.Simuliidae: Several species of the genus Simulium (family Simuliidae) that act as intermediate hosts (vectors) for the parasitic disease ONCHOCERCIASIS.Leukemia Virus, Murine: Species of GAMMARETROVIRUS, containing many well-defined strains, producing leukemia in mice. Disease is commonly induced by injecting filtrates of propagable tumors into newborn mice.DNA, Complementary: Single-stranded complementary DNA synthesized from an RNA template by the action of RNA-dependent DNA polymerase. cDNA (i.e., complementary DNA, not circular DNA, not C-DNA) is used in a variety of molecular cloning experiments as well as serving as a specific hybridization probe.Genome, Viral: The complete genetic complement contained in a DNA or RNA molecule in a virus.Viral Proteins: Proteins found in any species of virus.Thymidine Kinase: An enzyme that catalyzes the conversion of ATP and thymidine to ADP and thymidine 5'-phosphate. Deoxyuridine can also act as an acceptor and dGTP as a donor. (From Enzyme Nomenclature, 1992) EC Repeat Sequences: Nucleotide sequences repeated on both the 5' and 3' ends of a sequence under consideration. For example, the hallmarks of a transposon are that it is flanked by inverted repeats on each end and the inverted repeats are flanked by direct repeats. The Delta element of Ty retrotransposons and LTRs (long terminal repeats) are examples of this concept.Transformation, Bacterial: The heritable modification of the properties of a competent bacterium by naked DNA from another source. The uptake of naked DNA is a naturally occuring phenomenon in some bacteria. It is often used as a GENE TRANSFER TECHNIQUE.Spumavirus: Genus of non-oncogenic retroviruses which establish persistent infections in many animal species but are considered non-pathogenic. Its species have been isolated from primates (including humans), cattle, cats, hamsters, horses, and sea lions. Spumaviruses have a foamy or lace-like appearance and are often accompanied by syncytium formation. SIMIAN FOAMY VIRUS is the type species.Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.Larva: Wormlike or grublike stage, following the egg in the life cycle of insects, worms, and other metamorphosing animals.Gene Expression Regulation, Viral: Any of the processes by which cytoplasmic factors influence the differential control of gene action in viruses.Capsid: The outer protein protective shell of a virus, which protects the viral nucleic acid.Algorithms: A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Dengue: An acute febrile disease transmitted by the bite of AEDES mosquitoes infected with DENGUE VIRUS. It is self-limiting and characterized by fever, myalgia, headache, and rash. SEVERE DENGUE is a more virulent form of dengue.Genes, Viral: The functional hereditary units of VIRUSES.Cell Line, Tumor: A cell line derived from cultured tumor cells.Chagas Disease: Infection with the protozoan parasite TRYPANOSOMA CRUZI, a form of TRYPANOSOMIASIS endemic in Central and South America. It is named after the Brazilian physician Carlos Chagas, who discovered the parasite. Infection by the parasite (positive serologic result only) is distinguished from the clinical manifestations that develop years later, such as destruction of PARASYMPATHETIC GANGLIA; CHAGAS CARDIOMYOPATHY; and dysfunction of the ESOPHAGUS or COLON.

CAR-dependent and CAR-independent pathways of adenovirus vector-mediated gene transfer and expression in human fibroblasts. (1/23054)

Primary fibroblasts are not efficiently transduced by subgroup C adenovirus (Ad) vectors because they express low levels of the high-affinity Coxsackie virus and adenovirus receptor (CAR). In the present study, we have used primary human dermal fibroblasts as a model to explore strategies by which Ad vectors can be designed to enter cells deficient in CAR. Using an Ad vector expressing the human CAR cDNA (AdCAR) at high multiplicity of infection, primary fibroblasts were converted from being CAR deficient to CAR sufficient. Efficiency of subsequent gene transfer by standard Ad5-based vectors and Ad5-based vectors with alterations in penton and fiber was evaluated. Marked enhancement of binding and transgene expression by standard Ad5 vectors was achieved in CAR-sufficient fibroblasts. Expression by AdDeltaRGDbetagal, an Ad5-based vector lacking the arginine-glycine-aspartate (RGD) alphaV integrin recognition site from its penton base, was achieved in CAR-sufficient, but not CAR-deficient, cells. Fiber-altered Ad5-based vectors, including (a) AdF(pK7)betagal (bearing seven lysines on the end of fiber) (b) AdF(RGD)betagal (bearing a high-affinity RGD sequence on the end of fiber), and (c) AdF9sK betagal (bearing a short fiber and Ad9 knob), demonstrated enhanced gene transfer in CAR-deficient fibroblasts, with no further enhancement in CAR-sufficient fibroblasts. Together, these observations demonstrate that CAR deficiency on Ad targets can be circumvented either by supplying CAR or by modifying the Ad fiber to bind to other cell-surface receptors.  (+info)

C-myc overexpression and p53 loss cooperate to promote genomic instability. (2/23054)

p53 monitors genomic integrity at the G1 and G2/M cell cycle checkpoints. Cells lacking p53 may show gene amplification as well as the polyploidy or aneuploidy typical of many tumors. The pathways through which this develops, however, are not well defined. We demonstrate here that the combination of p53 inactivation and c-myc overexpression in diploid cells markedly accelerates the spontaneous development of tetraploidy. This is not seen with either N-myc or L-myc. Tetraploidy is accompanied by significantly higher levels of cyclin B and its associated cdc2 kinase activity. Mitotic spindle poisons accelerate the appearance of tetraploidy in cells either lacking functional p53 or overexpressing c-myc whereas the combination is additive. Restoration of p53 function in cells overexpressing c-myc causing rapid apoptosis, indicating that cells yet to become tetraploid have nonetheless suffered irreversible genomic and/or mitotic spindle damage. In the face of normal p53 function, such damage would either be repaired or trigger apoptotis. We propose that loss of p53 and overexpression of c-myc permits the emergence and survival of cells with increasingly severe damage and the eventual development of tetraploidy.  (+info)

Telomerase activity is sufficient to allow transformed cells to escape from crisis. (3/23054)

The introduction of simian virus 40 large T antigen (SVLT) into human primary cells enables them to proliferate beyond their normal replicative life span. In most cases, this temporary escape from senescence eventually ends in a second proliferative block known as "crisis," during which the cells cease growing or die. Rare immortalization events in which cells escape crisis are frequently correlated with the presence of telomerase activity. We tested the hypothesis that telomerase activation is the critical step in the immortalization process by studying the effects of telomerase activity in two mortal SVLT-Rasval12-transformed human pancreatic cell lines, TRM-6 and betalox5. The telomerase catalytic subunit, hTRT, was introduced into late-passage cells via retroviral gene transfer. Telomerase activity was successfully induced in infected cells, as demonstrated by a telomerase repeat amplification protocol assay. In each of nine independent infections, telomerase-positive cells formed rapidly dividing cell lines while control cells entered crisis. Telomere lengths initially increased, but telomeres were then maintained at their new lengths for at least 20 population doublings. These results demonstrate that telomerase activity is sufficient to enable transformed cells to escape crisis and that telomere elongation in these cells occurs in a tightly regulated manner.  (+info)

Stabilization of poly-L-lysine/DNA polyplexes for in vivo gene delivery to the liver. (4/23054)

We are developing a self-assembling non-viral in vivo gene delivery vehicle based on poly-l-lysine and plasmid DNA. We have characterized poly-l-lysines of different chain lengths for DNA condensation and strength of DNA binding. Poly-l-lysine chains >20 residues bound DNA efficiently in physiological saline, while shorter chains did not. Attachment of asialoorosomucoid to PLL increased the PLL chain length required for efficient DNA binding in saline and for efficient DNA condensation. By electron microscopy, poly-l-lysine/DNA polyplexes appeared as toroids 25-50 nm in diameter or rods 40-80 nm long; conjugation of asialoorosomucoid to the polylysine component increased the size of resulting polyplexes to 50-90 nm. In water, poly-l-lysine and asialoorosomucoid-PLL polyplexes have effective diameters of 46 and 87.6 nm, respectively. Polyplexes containing only poly-l-lysine and DNA aggregated in physiological saline at all charge ratios and aggregated at neutral charge ratios in water. Attachment of asialoorosomucoid lessened, but did not eliminate, the aggregation of PLL polyplexes, and did not result in efficient delivery of polyplexes to hepatocytes. Conjugation of polyethylene glycol to poly-l-lysine sterically stabilized resulting polyplexes at neutral charge ratios by shielding the surfaces. For efficient in vivo gene delivery, polyplexes will need to be sterically stabilized to prevent aggregation and interaction with serum components.  (+info)

Deletion of multiple immediate-early genes from herpes simplex virus reduces cytotoxicity and permits long-term gene expression in neurons. (5/23054)

Herpes simplex virus type 1 (HSV-1) has many attractive features that suggest its utility for gene transfer to neurons. However, viral cytotoxicity and transient transgene expression limit practical applications even in the absence of viral replication. Mutant viruses deleted for the immediate early (IE) gene, ICP4, an essential transcriptional transactivator, are toxic to many cell types in culture in which only the remaining IE genes are expressed. In order to test directly the toxicity of other IE gene products in neurons and develop a mutant background capable of longterm transgene expression, we generated mutants deleted for multiple IE genes in various combinations and tested their relative cytotoxicity in 9L rat gliosarcoma cells, Vero monkey kidney cells, and primary rat cortical and dorsal root neurons in culture. Viral mutants deleted simultaneously for the IE genes encoding ICP4, ICP22 and ICP27 showed substantially reduced cytotoxicity compared with viruses deleted for ICP4 alone or ICP4 in combination with either ICP22, ICP27 or ICP47. Infection of neurons in culture with these triple IE deletion mutants substantially enhanced cell survival and permitted transgene expression for over 21 days. Such mutants may prove useful for efficient gene transfer and extended transgene expression in neurons in vitro and in vivo.  (+info)

Inducible long-term gene expression in brain with adeno-associated virus gene transfer. (6/23054)

Recombinant adeno-associated virus (rAAV) vectors hold promise for treating a number of neurological disorders due to the ability to deliver long-term gene expression without toxicity or immune response. Critical to these endeavors will be controlled expression of the therapeutic gene in target cells. We have constructed and tested a dual cassette rAAV vector carrying a reporter gene under the control of the tetracycline-responsive system and the tetracycline transactivator. Transduction in vitro resulted in stable expression from the vector that can be suppressed 20-fold by tetracycline treatment. In vivo experiments, carried out to 6 weeks, demonstrated that vector-transduced expression is sustained until doxycycline administration upon which reporter gene expression is reduced. Moreover, the suppression of vector-driven expression can be reversed by removal of the drug. These studies demonstrate long-term regulated gene expression from rAAV vectors. This system will provide a valuable approach for controlling vector gene expression both in vitro and in vivo.  (+info)

Adenoviral gene transfer into the normal and injured spinal cord: enhanced transgene stability by combined administration of temperature-sensitive virus and transient immune blockade. (7/23054)

This study characterized gene transfer into both normal and injured adult rat dorsal spinal cord using first (E1-/E3-) or second (E1-/E2A125/E3-, temperature-sensitive; ts) generation of replication-defective adenoviral (Ad) vectors. A novel immunosuppressive regimen aimed at blocking CD4/CD45 lymphocytic receptors was tested for improving transgene persistence. In addition, the effect of gene transfer on nociception was also evaluated. Seven days after treatment, numerous LacZ-positive cells were observed after transfection with either viral vector. By 21 days after transfection, beta-galactosidase staining was reduced and suggestive of ongoing cytopathology in both Ad-treated groups, despite the fact that the immunogenicity of LacZ/Adts appeared less when compared with that elicited by the LacZ/Ad vector. In contrast, immunosuppressed animals showed a significant (P < or = 0.05) increase in the number of LacZ-positive cells not displaying cytopathology. In these animals, a concomitant reduction in numbers of macrophages/microglia and CD4 and CD8 lymphocytes was observed. Only animals that received LacZ/Adts and immunosuppression showed transgene expression after 60 days. Similar results were observed in animals in which the L4-L5 dorsal roots were lesioned before transfection. Gene transfer into the dorsal spinal cord did not affect nociception, independent of the adenovirus vector. These results indicate that immune blockade of the CD4/CD45 lymphocytic receptors enhanced transgene stability in adult animals with normal or injured spinal cords and that persistent transgene expression in the spinal cord does not interfere with normal neural function.  (+info)

Antitumor effect of allogenic fibroblasts engineered to express Fas ligand (FasL). (8/23054)

Fas ligand is a type II transmembrane protein which can induce apoptosis in Fas-expressing cells. Recent reports indicate that expression of FasL in transplanted cells may cause graft rejection and, on the other hand, tumor cells may lose their tumorigenicity when they are engineered to express FasL. These effects could be related to recruitment of neutrophils by FasL with activation of their cytotoxic machinery. In this study we investigated the antitumor effect of allogenic fibroblasts engineered to express FasL. Fibroblasts engineered to express FasL (PA317/FasL) did not exert toxic effects on transformed liver cell line (BNL) or colon cancer cell line (CT26) in vitro, but they could abrogate their tumorigenicity in vivo. Histological examination of the site of implantation of BNL cells mixed with PA317/FasL revealed massive infiltration of polymorphonuclear neutrophils and mononuclear cells. A specific immune protective effect was observed in animals primed with a mixture of BNL or CT26 and PA317/FasL cells. Rechallenge with tumor cells 14 or 100 days after priming resulted in protection of 100 or 50% of animals, respectively. This protective effect was due to CD8+ cells since depletion of CD8+ led to tumor formation. In addition, treatment of pre-established BNL tumors with a subcutaneous injection of BNL and PA317/FasL cell mixture at a distant site caused significant inhibition of tumor growth. These data demonstrate that allogenic cells engineered with FasL are able to abolish tumor growth and induce specific protective immunity when they are mixed with neoplastic cells.  (+info)

  • Selfish genetic elements (historically also referred to as selfish genes , ultra-selfish genes , selfish DNA , parasitic DNA and genomic outlaws ) are genetic segments that can enhance their own transmission at the expense of other genes in the genome, even if this has no positive or a net negative effect on organismal fitness. (
  • The pCambia-1301-35SN vector containing the CaMV 35S promoter and the β-glucuronidase ( GUS ) and Superfolder green fluorescence protein (SG) as reporter genes were introduced into the plant tissues by the Agrobacterium -mediated transformation system. (
  • Novel transformation vectors containing novel chimeric genes allow the introduction of exogenous DNA fragments coding for polypeptide toxins produced by Bacillus thuringiensis or having substantial sequence homology to a gene coding for a polypeptide toxin as described herein and expression of the chimeric. (
  • This vector is capable of delivering and expressing foreign genes in infected cells including progenitor cells such as human CD34+ cells. (
  • Viral vectors can be used to modify specific cell type or tissue and can be directed to express therapeutic genes. (
  • These unique abilities made them desirable for engineering viral vectors to deliver the therapeutic genes. (
  • Indeed, vectors pseudotyped with RD114 Env are very efficient to transfer genes into human hematopoietic cells, and they are resistant to human complement inactivation. (
  • Authors are urged to use these rules when naming genes or other genetic structures to avoid unsystematic and duplicate names. (
  • It contains the elements required for vector packaging such as structural proteins, HIV genes (except the gene env because its presence would enable the virus to infect T-cells) and the enzymes that generate vector particles. (
  • To predict the remaining life of ball screw, a screw remaining life prediction method based on quantum genetic algorithm (QGA) and support vector machine (SVM) is proposed. (
  • Support vector machines and artificial neural network techniques are used to classify the aggregates using a methodology to tune the algorithm parameters to improve the performance of the models. (
  • We used a combination of genetic algorithm as an optimizer and support vector machines as a classifier for the identification of maximally-effective waveband combination. (
  • The protocol will facilitate more detailed and ethically advantageous sampling of schistosome populations for genetic profiling. (
  • In Montana, several introduced populations have been reported, but little is known of their sources and vectors of introduction and secondary spread. (
  • We evaluated the genetic composition of introduced populations at local (Yellowstone River floodplain) and regional (Montana and Wyoming) scales in contrast to native range populations. (
  • Ecological and genetic changes in vector populations of dengue fever in relation to urbanization. (
  • In Southeast Asia, the low differentiation and the high co-ancestry values identified among China, Thailand and Japan indicate that, in the native range, these populations maintain high genetic connectivity, revealing their ancestral common origin. (
  • Outside Southeast Asia, the invasion process in La Réunion, America and the Mediterranean Basin is primarily supported by a chaotic propagule distribution, which cooperates in maintaining a relatively high genetic diversity within the adventive populations. (
  • mosquito populations from Europe are screening legs, and transmission rates by screening saliva, competent vectors for Zika virus ( 3,4 ). (
  • The reason for this geographical heterogeneity and why different patients develop different clinical forms poses the question of its relationship to the genetic heterogeneity of T. cruzi populations in different areas. (
  • T. cruzi multiclonal populations differs in genetic and biological characteristics and in their behavior in the vertebrate host (Andrade & Magalhaes 1997). (
  • The vector was designed by Dr. Matthew During, professor of molecular virology, immunology and medical genetics and of neuroscience and neurological surgery at Ohio State, in collaboration with Robert MacLaren, professor of ophthalmology at the University of Oxford, who also leads the trial. (
  • Observations of what is now referred to as selfish genetic elements go back to the early days in the history of genetics . (
  • Ticks (subphylum Chelicerata: suborder Ixodida) are notorious ectoparasites and vectors of human and animal pathogens, transmitting a greater diversity of infectious agents than any other group of blood-feeding arthropods. (
  • Previous surveys in dogs from Korea indicated that dogs are exposed to a variety of vector- borne pathogens, but perception for a nation-wide canine vector-borne disease (CVBD) occurrence has been missing. (
  • New Rochelle, NY, August 13, 2018--A new study has shown that a single injection of a novel adeno-associated vector (AAV)-based therapy can result in improved enzyme activ-ity and glycogen clearance as well as prolonged survival in a mouse model of Pompe dis-ease. (
  • Here, we discuss the salient advances in the prevention and control strategies to combat ZIKV with a focus on highlighting various intervention approaches against the vector mosquitoes of this viral pathogen along with presenting an overview regarding human intervention measures to counter other modes of ZIKV transmission and spread. (
  • Here we present the principles, associated opportunities and risks, as well as the degree of advancement of these various techniques for a subset of livestock pests and disease vectors including screwworms, tsetse, mosquitoes and stomoxes. (
  • The following rules for the genetic and molecular nomenclature of all mosquitoes are proposed. (
  • Genetic diversity of C. hominis and C. parvum may therefore be an independent and complementary measure for quantifying disease incidence, for which only a moderate number of stool samples from each nation are sufficient data input. (
  • A classification approach is introduced with Genetic Fuzzy based Improved Kernel Support Vector machine (GF-IKSVM) classifier and a BICA based feature selection for the classification of cardiovascular heart disease dataset. (
  • Bois Noir is caused by Candidatus Phytoplasma solani, cell wall-less bacteria belonging to the taxonomic group 16Sr-XII-A. In Germany, they are known to be vectored from plant to plant by the cixiid Hyalesthes obsoletus , but so far the prevalence of the disease in the vector population, as well as its spatio-temporal distribution is poorly understood. (
  • New opportunities for researchers to work in top-level facilities on different disease vectors, including the sandfly (pictured) are also posted on the site. (
  • Other effects may include changes in agricultural yields, addition of new trade routes, reduced summer streamflows, species extinctions, and increases in the range of disease vectors. (
  • Genetic rearrangements occurring during a single cycle of murine leukemia virus vector replication: characterization and implications. (
  • The focus of this report is to examine the spectrum of genomic rearrangements arising during a single cycle of Moloney murine leukemia virus (MoMLV) vector virus replication. (
  • These vectors can be used for allelic exchange in a wide variety of bacterial species because their R6K origin of replication functions only in bacteria engineered to produce the replication protein pi. (
  • This vector is based on the herpes simplex virus (HSV) amplicon system and contains the HCMV orthologs of the two cis -acting functions required for replication and packaging of HSV genomes, the complex HCMV viral DNA replication origin (oriLyt), and the cleavage packaging signal (the a sequence). (
  • Broad spectrum of in vivo forward mutations, hypermutations, and mutational hotspots in a retroviral shuttle vector after a single replication cycle: deletions and deletions with insertions. (
  • The insert capacity of pFB, our MMLV-based replication-defective pFB vector, is approximately 8.0 kb because there is no extraneous sequence between the LTRs. (
  • Target cells such as the patient's liver or lung cells are infected with the viral vector. (
  • During and his colleagues designed the viral vector to infect the light-sensitive photoreceptor cells that line the back of the eye and make up the retina. (
  • MoMLV vector virus was produced in packaging lines, and target cells were infected. (
  • They were examining bacteria from cystic fibrosis patients who had acquired chronic B. dolosa infections, expecting the B. dolosa cells from later samples to look like genetic descendants of those in earlier samples. (
  • Instead of studying single isolates, the researchers cultured many cells from each patient and conducted two kinds of genetic sequencing (colony resequencing and deep population sequencing) to reveal B. dolosa 's genetic diversity. (
  • Viruses naturally possess specialized molecular mechanisms to efficiently transfer their genetic materials into the infected cells. (
  • Gene vectors that insert themselves into the host genome would allow for a long-lasting phenotypic correction even if the target cells undergo repeated rounds of cell division. (
  • The process of gene transfer into the cells is achieved by the application of vectors. (
  • They are known for transferring genetic material between cells and they do it by a proteinaceous filament called sex pilus. (
  • To counteract this problem, we constructed and validated a set of high-titer retroviral reporter vectors based on the pFB vector, which can be used to assess transduction efficiency and readily assay for gene expression in infected cells lines. (
  • The vector was then tested in retrovirally transduced cells. (
  • For experiments in which cells were infected at a low multiplicity of infection (MOI) and, thus, harbor only single copies of the hrGFP provirus, fluorescence over background was readily detectable with this vector. (
  • METHODS: RD114-pseudotyped vectors produced from the FLYRD18 packaging cells were added on tumor cell lines, and the formation of syncytia was assessed by microscopy after cell fixation and methylene blue staining. (
  • Finally, the cytotoxic effect of RD114-pseudotyped vectors was measured by the MTT assay on tumor cells, and in combination with the TK/GCV strategy. (
  • A few hours after addition of the vector, cells started to aggregate to form syncytia that eventually evolved toward cell death 48 h postinfection. (
  • RD114-pseudotyped vectors were very efficient at killing human cancer cells, and they were also able to enhance dramatically the cytotoxic effect of the TK/GCV strategy. (
  • This whole process then repeats itself, leading to the accumulation of serious imbalances in the genetic information of the daughter cells. (
  • The HCMV amplicon vector replicated independently and was packaged into infectious virions in the presence of helper virus. (
  • Due to immune responses caused by a high dose of adenoviral vector containing OTC, Gelsinger died four days later because of multi-organ failure . (
  • Synthesis of data from published human genetic association studies is a critical step in the translation of human genome discoveries into health applications. (
  • Genome sequence map, chromosome architecture and genetic sequencing chart abstract data. (
  • Though long dismissed as genetic curiosities, with little relevance for evolution, they are now recognized to affect a wide swath of biological processes, ranging from genome size and architecture to speciation. (
  • Because the whole-genome sequence of D. officinale is publicly available, this species is poised to become a convenient research model for the evolutionary, developmental, and genetic studies of Orchidaceae. (
  • However, gene vectors, which insert themselves into the host genome in order to achieve persistent protein expression, can trigger oncogenesis by upregulating cellular protooncogenes. (
  • In this study, we focused on the improvement of gene delivery efficiency of a newly emerged viral vector originated from insect viruses, namely baculovirus. (
  • EU funding allows Infravec2 to provide researchers worldwide with insect vector research products and services at no cost to the recipients. (
  • New genetic control methods, related to the ancestral sterile insect technique (SIT), show particular promise and are being developed in response to increasing health and agricultural challenges. (
  • As a consequence, a great amount of intra-population variability has been detected, and it is likely that this variability may extend to the genetic mechanisms controlling vector competence. (
  • T. cruzi is a parasitic protozoan that consists of a heterogeneous population composed of a pool of strains circulating in both the domestic and sylvatic cycles in humans, vectors, and animal reservoirs (Souto et al. (
  • Based on 296 C. hominis and 195 C. parvum GP60 sequences from human origin, the genetic diversities of Cryptosporidium was estimated for several nations. (
  • In other words, the exposure to infectious oocysts in a human population could be indirectly measured by quantifying the genetic diversities of C. hominis and C. parvum DNA sequences, as found in human fecal samples. (
  • Adenoviral vectors with all viral coding sequences deleted offer the prospect of decreased host immune responses to viral proteins, decreased cellular toxicity of viral proteins and increased capacity to accommodate large regulatory DNA regions. (
  • 107 Pages Report] The global viral vector manufacturing market was valued at USD 273.2 million in 2017 and is expected to grow at a CAGR of 20.0% during the forecast period to reach to USD 815.8 million by 2023. (
  • In the USA, Ixodes scapularis also vectors the infectious agents that cause human babesiosis, human granulocytic anaplasmosis, tick-borne relapsing fever and Powassan encephalitis. (
  • This review provides a survey of these advances as well as several remaining challenges, focusing in particular on the importance of achieving adequate levels of protein expression from a limited number of vector copies per cell-ideally one to two. (
  • In mice and flies, the Arc protein forms capsids and carries genetic information. (
  • In this report, we show that these vectors can be used to efficiently introduce point mutations and deletions into the chromosome of Vibrio cholerae. (
  • The genus Ixodes includes multiple species of medical and veterinary importance, most notably serving as vectors of Lyme borreliosis in North America, Europe and Asia. (
  • however, there is still work to be done in improvements to the vector system and moving the in vitro studies in vivo . (
  • Adenoviral vectors are frequently used for gene transfer because of their high cellular transduction efficiency in vitro and in vivo. (
  • Currently most vectors used in vivo for preclinical and clinical studies express cDNAs under the control of heterologous eukaryotic or viral promoters. (
  • In 2017, the European Commission gave its go-ahead to Infravec2, the EU-funded global source for no-cost vector research products and services. (
  • The hypothesis that genetic diversity at GP60 locus mirrors notification rates of human cryptosporidiosis was not rejected based on the data presented. (
  • Here, we test the hypothesis that the genetic diversity of Cryptosporidium at the GP60 locus from human isolates positively correlates with the population risk. (
  • Selfish genetic elements have now been described in most groups of organisms, and they demonstrate a remarkable diversity in the ways by which they promote their own transmission. (
  • Then, in the early 1950s, Barbara McClintock published a series of papers describing the existence of transposable elements , which are now recognized to be among the most successful selfish genetic elements. (
  • By comparing the genotoxicity of vectors with matched active LTRs, we were able to determine that substantially greater LV integration loads are required to approach the same oncogenic risk as γRVs. (
  • Our findings strongly support the use of SIN viral vector platforms and show that ISS can substantially modulate genotoxicity. (