Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.5.1.3 (dihydrofolate reductase)
 5,819 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Patterns of deoxyribonucleic acid (DNA) metabolism in nonpermissive cells infected with amber mutants representing 29 genes of T5 are reported. A group of 7 contiguous genes are essential for the synthesis of phage DNA, whereas 20 other genes, when defective, permit varying degrees of phage DNA synthesis. Two further genes are essential for complete transfer of phage DNA to host cells, and therefore indirectly do not permit the synthesis of phage DNA. The structural genes for an early T5 deoxyribonuclease and for T5 DNA polymerase, as well as a gene that affects the synthesis of dihydrofolate reductase, have been identified in the genetic map of T5.
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PMID:Genetic and physiological studies of bacteriophage T5. 3. Patterns of deoxyribonucleic acid synthesis induced by mutants of T5 and the identification of genes influencing the appearance of phage-induced dihydrofolate reductase and deoxyribonuclease. 455 11

Mammalian cells are often used for the expression of recombinant proteins. The process of screening transfected cells randomly for high producing clones is tedious and time consuming. We evaluated using green fluorescent protein (GFP) for selection of high producing clones by fluorescence-activated cell sorter (FACS) to reduce screening effort. We expressed neurotrophin-3 (NT3), deoxyribonuclease (DNase), or vascular endothelial growth factor (VEGF) with GFP in Chinese hamster ovary cells. The vector expressed the desired secreted protein and the selectable marker, dihydrofolate reductase, in one expression unit and the intracellular GFP in a second expression unit. Transfected cells were grown in selection medium and sorted by FACS. High fluorescence clones were obtained and found to produce high amounts of the desired protein; VEGF productivity correlated well with GFP fluorescence in 48 clones. Further studies demonstrated that productivity correlated very well with RNA of the desired protein. For comparison, we randomly picked and screened 144 VEGF clones, and the highest producing VEGF clone obtained produced 0.7 pg/cell/day. In contrast, the highest producing VEGF clone obtained by FACS sorting produced 4.4 pg/cell/day. FACS sorting therefore selected high producing clones efficiently. Since an assay for the desired protein is not required, high producing clones for a protein of unknown function can be obtained by FACS sorting followed by measuring the RNA level of the desired protein in the highly fluorescent clones.
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PMID:Green fluorescent protein as a second selectable marker for selection of high producing clones from transfected CHO cells. 1072 13

Receptor mediated delivery of siRNA enables silencing of target genes in specific tissues. Folate receptor (FR) is an attractive target for tumor-selective gene delivery. The focus of this study was to deliver the dihydrofolate reductase (DHFR) siRNA expressing plasmid and to silence the DHFR gene in FR positive KB cells, by complexing the plasmid with a folate-polyethylene glycol-polyethylenimine (FOL-PEG-PEI) conjugate, as a gene carrier. A DHFR siRNA sequence was cloned into a pSUPER-RNAi vector and complexed with the FOL-PEG-PEI conjugate. The complex was characterized by particle size analyzer, gel retardation and DNase protection assay. The FOL-PEG-PEI/pSUPER-siDHFR complex was transfected to FR overexpressing (KB) and FR negative (A549) cells. The transfection effiencies and gene inhibition were analyzed by fluorescence microscopy and RT-PCR. The pSUPER-siDHFR/PEI-PEG-FOL complex delivered the siRNA vector and inhibited DHFR gene in KB cells, while A549 cells were unaffected. Lipofectamine mediated transfection of pSUPER-siDHFR, delivered the vector and inhibited the DHFR gene in both KB and A549 cells. FR mediated delivery of siDHFR complexed with PEI-PEG-FOL conjugate inhibits the DHFR expression in FR positive cells alone. This strategy can be extended to deliver a wide range of drugs and post-transcriptional gene silencing therapeutics.
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PMID:Development of a targeted siRNA delivery system using FOL-PEG-PEI conjugate. 1981 91