Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.23 (beta-galactosidase)
 14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A gene encoding the Tilapia mossambica (Oreochromis mossambicus) growth hormone (tiGH) was isolated and sequenced. The gene spans 5.6 kb, including 3.7 kb of 5' and 0.2 kb of 3' flanking sequences and a 1.7-kb transcription unit comprised of six exons and five introns. The gene and the 5' flanking region contain several potential binding sites for Pit-1, a key transcription activator of mammalian GH genes. One of these (-57/-42) is highly conserved in fish GH genes. It activates transcription in pituitary cells and binds Pit-1. Transfection of luciferase reporter plasmids containing either the -3602/+19 tiGH sequence or one of its 5' deletion mutants (-2863/, -1292/, and -463/+19) resulted in strong activity in Pit-1-producing rat pituitary GC cells. A dose-dependent activation of the tiGH promoter was achieved in nonpituitary fish EPC and monkey COS cells cotransfected with a rat Pit-1 expression vector, demonstrating the crucial role played by Pit-1 as an activator of the tiGH gene. Fusion of the tiGH promoter with the beta-galactosidase gene led to transient expression specifically in the nervous system of microinjected zebrafish embryos. The activity of the tiGH promoter in GC and EPC cells was strongly repressed by extending its 3' end from +19 to +40, a sequence in which a Pit-1-binding site was identified using gel retardation assays. Point mutations of the site that suppressed Pit-1 binding in vitro restored full tiGH promoter activity. Thus, a Pit-1-binding site located in the 5' untranslated region mediates Pit-1-dependent repression of the tiGH gene.
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PMID:Structure and functional analysis of a tilapia (Oreochromis mossambicus) growth hormone gene: activation and repression by pituitary transcription factor Pit-1. 1039 Jan 58

Five fish cell lines were tested for their ability to be transduced by Ac-CAlacZ, a recombinant baculovirus that is capable of expressing a beta-galactosidase reporter gene from the CAG promoter (consisting of a cytomegalovirus enhancer element, a chicken actin promoter and rabbit beta-globin termination sequences). TO (Tilapia ovary), EPC (carp), CHH-1 (Chum salmon heart fibroblast) and CHSE-214 (chinook salmon embryo) cells were transducible, as demonstrated by an in situ beta-galactosidase assay, whereas RTG-2 (rainbow trout gonad) cells were not. The EPC cell line was used for more detailed studies on baculovirus transduction. The transduction frequency was found to be higher at 28 degrees C than at 21 degrees C. Addition of the histone deacetylase inhibitor sodium butyrate increased the number of blue cells detected 5- to 7-fold. The m.o.i. was positively correlated with transduction frequency, although the relationship did not appear to be strictly linear, as has been observed with mammalian cells. The temperature at which baculoviruses were adsorbed to EPC cells did not affect levels of beta-galactosidase expression. We also examined expression levels of beta-galactosidase in EPC cells after infection with a baculovirus construct that overexpresses the vesicular stomatitis virus G protein and displays it on the virion surface. Expression levels with this virus were approximately 15-fold higher than were observed with Ac-CAlacZ.
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PMID:Transduction of cultured fish cells with recombinant baculoviruses. 1269 82

Cationic polysaccharides were synthesized by conjugation of various monoquaternary (MQ) ammonium oligoamines to oxidized dextran by reductive amination and tested for gene transfection. Polycations of dextran grafted with MQ ammonium oligoamines of two to four amino groups were investigated for their ability to cause pCMV-GFP encoding for green fluorescence protein and beta-Gal encoding for beta-galactosidase protein transfection on EPC and HEK-293 cell lines. These polycations were expected to strongly complex DNA due to increased surface cationic charge of the carrier, which may result in a higher transfection yield. However, the transfection yields were much lower compared to the parent vector, dextran-spermine conjugate, which was highly effective both in vitro and in vivo.
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PMID:Quaternary ammonium polysaccharides for gene delivery. 1617 98

Recent studies have suggested that reduced endothelial progenitor subpopulation in lectin-binding and DiLDL-uptaking cell (EPC subpopulation) number and activity was associated with EPC subpopulation senescence that involved telomerase activity and telomere length. Stromal cell-derived factor-1alpha (SDF-1alpha) has been shown to augment a variety of cellular functions of EPC subpopulation and subsequently contribute to ischemic neovascularization. Therefore, we investigated whether SDF-1alpha might be able to prevent senescence of EPC subpopulation and also investigated the effects of SDF-1alpha on the telomerase activity and telomere length. EPC subpopulation were isolated from peripheral blood and characterized. After ex vivo prolonged cultivation, EPC subpopulation became senescent as determined by acidic beta-galactosidase staining. SDF-1alpha dose-dependently inhibited the onset of EPC subpopulation senescence. Moreover, SDF-1alpha increased proliferation and colony-forming activity of EPC subpopulation. SDF-1alpha also increased telomerase activity and telomere length, which was accompanied with upregulation of the catalytic subunit, telomerase reverse transcriptase (TERT). Whereas these effects of SDF-1alpha on telomerase activity and expression of hTERT mRNA were significantly attenuated by CXCR4-specific peptide antagonist (AMD3100) and phosphoinositide 3-kinase (PI3K) inhibitor (LY294002). In conclusions, SDF-1alpha delays the onset of EPC subpopulation senescence, which may be related to the activation of telomerase and elongation of telomere length. The inhibition of EPC subpopulation senescence and induction of EPC subpopulation proliferation by SDF-1alpha in vitro may importantly improve the functional activity of EPC subpopulation for potential cell therapy.
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PMID:Stromal cell-derived factor 1alpha reduces senescence of endothelial progenitor subpopulation in lectin-binding and DiLDL-uptaking cell through telomerase activation and telomere elongation. 2023 1