Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.2.1.23 (beta-galactosidase)
14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Accumulation of intracellular cyclic adenosine monophosphate (cAMP) has been shown to inhibit the growth of cultured airway smooth-muscle cells, but the precise mechanism underlying the antimitogenic action of cAMP in these cells is unknown. We examined the effects of forskolin, an activator of adenylate cyclase, on DNA synthesis, cyclin D1 expression, and cAMP response element-binding protein (CREB) phosphorylation and DNA binding in bovine tracheal myocytes. DNA synthesis was assessed by measurement of [3H]thymidine incorporation. Cyclin D1 protein abundance and CREB phosphorylation were assessed by immunoblotting. Cyclin D1 promoter transcriptional activation was determined by measurement of luciferase activity in cells transiently cotransfected with complementary DNAs encoding the full-length cyclin D1 promoter subcloned into a luciferase reporter and beta-galactosidase (to normalize for transfection efficiency). The binding of nuclear proteins to the cyclin D1 promoter cAMP response element (CRE) was determined by electrophoretic mobility shift assay. We found that forskolin attenuated platelet-derived growth factor-induced DNA synthesis in a concentration-dependent manner. In addition, forskolin pretreatment decreased both cyclin D1 promoter activity and protein levels. Forskolin treatment induced the phosphorylation of CREB and increased the binding of nuclear protein to the cyclin D1 promoter CRE. Finally, addition of an antibody against CREB1 induced supershift of at least one protein-DNA complex. Together, these data suggest that cAMP suppresses cyclin D1 gene expression via phosphorylation and transactivation of CREB. Further studies are needed to determine whether this is the primary mechanism of cAMP-induced growth inhibition, or whether additional pathways are also involved.
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PMID:Forskolin inhibits cyclin D1 expression in cultured airway smooth-muscle cells. 992 28

We explored a novel approach to the functional regulation of nuclear proteins; altering their subcellular localization. To anchor a nuclear protein, beta-galactosidase with the nuclear localization signal of SV40 (nbeta-gal), within the cytoplasm, nbeta-gal was fused to the transmembrane domain of granulocyte colony-stimulating factor receptor (G-CSFR), a membrane protein. To liberate the nbeta-gal portion from the fusion protein, we used a protease derived from a plant virus, whose recognition sequence was inserted between the G-CSFR and nbeta-gal. Western analysis showed that the chimeric protein was cleaved in the presence of the protease in 293 cells and that the fusion protein without the recognition sequence remained intact. This chimeric protein was localized exclusively in the cytoplasm as visualized by X-gal staining and immunofluorescence microscopy. In contrast, when expressed together with the protease, beta-gal was predominantly detected in the nuclei. Moreover, we isolated 293-cell clones constitutively expressing the protease, indicating that this protease is not cytotoxic. These results suggest that the viral protease-mediated alteration of subcellular localization can potentially regulate the function of nuclear proteins.
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PMID:A switching system regulating subcellular localization of nuclear proteins using a viral protease. 1058 Nov 71

The polypeptide ligand angiogenin, a potent inducer of angiogenesis, localizes in the nucleus/nucleolus subsequent to endocytosis by relevant cell types. This study examines the kinetic properties of the nucleolar targeting signal (NTS) of angiogenin (IMRRRGL(35)) at the single cell level. We show that the NTS is sufficient to target green fluorescent protein (GFP), but not beta-galactosidase, to the nucleolus of rat hepatoma cells. Mutation of Arg(33) to Ala within the NTS abolishes targeting activity. Nuclear/nucleolar import conferred by the NTS of angiogenin is reduced by cytosolic factors as well as ATP and is independent of importins and Ran. The NTS also confers the ability to bind to nuclear/nucleolar components which is inhibited by ATP hydrolysis; nonhydrolysable GTP analogs prevent nuclear accumulation in the absence of an intact nuclear envelope through an apparent cytoplasmic retention mechanism. Since the lectin wheat germ agglutinin does not inhibit transport, we postulate a mechanism for angiogenin nuclear/nucleolar import involving passive diffusion of angiogenin through the nuclear pore and NTS-mediated nuclear/nucleolar retention, and with cytoplasmic retention modulating the process. This pathway is clearly distinct from that of conventional signal-mediated nuclear protein import.
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PMID:Novel properties of the nucleolar targeting signal of human angiogenin. 1137 89

It was found previously that Ecm11 interacts with Cdc6 in a two-hybrid screen. To verify that these two gene products can actually encounter in the living cell, ECM11 was expressed as a fusion with GFP. The fusion protein was located in the cell nucleus throughout all stages of mitosis. The protein was detected in discrete clusters in the nucleus. Clusters may be due to Ecm11 protein polymerisation and association with discrete structures in the nucleus. Two Ecm 11 molecules interact in the two-hybrid assay, suggesting the presence of functional dimmers. Ecm11 does not promote transcription of beta-galactosidase reporter gene, when fused with LexA DNA binding domain and fetch to the promoter of the reporter gene. According to our observation, we suppose that Ecm11 is a nuclear protein involved in the upholding chromatin structure.
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PMID:Ecm11 is located in the cell nucleus throughout mitosis. 1167 31

M32 [also termed chromatin modifier protein 2 (MOD2)] is a nuclear protein consisting of the condensed chromatin structure (heterochromatin) and considered one of the mammalian homologues of heterochromatin protein 1 (HP1), first isolated as one of the components of heterochromatin in Drosophila. This report presents the isolation and characterization of the 5'-upstream region of the mouse M32 gene containing a promoter region and 5'-untranslated region (5'-UTR) exon. The 5'-upstream region (approximately 0.27 kb starting from the 5' end of the 5'-UTR exon) of the M32 gene contained neither a TATA box nor a CCAAT box, but possessed potential binding sites for transcription factors such as Sp1, H4TF-1, PEA2, PEA3, GSG element and Egr-1, and was highly G/C-rich. The promoter activity of this 5'-upstream region was demonstrated by transfecting its fusion-construct with the E. coli beta-galactosidase gene into the F9 mouse teratocarcinoma cell line. The 5' ends of the mRNA were mapped to at least two positions in the 5'-upstream region. Interestingly, the 5'-upstream region exhibited a high degree of similarity to a portion of heterogeneous nuclear ribonucleoprotein (hnRNP) A2/B1 gene, which is thought to play a role in RNA processing, located in the reverse orientation to the M32 gene, and also to several known ESTs and cDNAs. These findings suggest that the 5'-upstream region of the M32 gene consists of a multiple regulatory complex which probably plays important roles in nuclear function such as chromatin organization and RNA processing.
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PMID:Cloning and characterization of 5'-upstream sequence of the M32 gene for a mouse homologue of Drosophila heterochromatin protein 1 (HP1). 1176 15

The primate striatum contains tyrosine hydroxylase (TH)-immunoreactive (ir) neurons, the numbers of which are augmented after dopamine depletion. Glial cell line-derived neurotrophic factor (GDNF) strongly modulates the viability and phenotypic expression of dopamine ventral mesencephalic neurons. The effect of GDNF on TH-ir neurons intrinsic to the striatum has yet to be investigated. In the present study, stereological counts of TH-ir striatal neurons in aged and parkinsonian nonhuman primates revealed that GDNF delivered via a lentiviral vector (lenti-) further increased the number of these cells. Aged monkeys treated with lenti-GDNF displayed an eightfold increase in TH-ir neurons relative to lenti-beta-galactosidase-treated monkeys. Unilateral 1-methyl-4-phenyl- 1,2,3,6-tetrahydropyridine treatment alone in young monkeys resulted in a bilateral eightfold increase in TH-ir striatal cells. This effect was further magnified sevenfold on the side of lenti-GDNF treatment. These cells colocalized with the neuronal marker neuronal-specific nuclear protein. Some of these cells colocalized with GDNF-ir, indicating that an alteration in phenotype may occur by the direct actions of this trophic factor. Thus, GDNF may mediate plasticity in the dopamine-depleted primate brain, which may serve to compensate for cell loss by converting striatal neurons to a dopaminergic phenotype.
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PMID:Lentivirally delivered glial cell line-derived neurotrophic factor increases the number of striatal dopaminergic neurons in primate models of nigrostriatal degeneration. 1207 91

To determine whether NF-kappaB activation is sufficient to generate lung inflammation in vivo, we selectively expressed a constitutively active form of IkappaB kinase 1 (cIKK1) or IkappaB kinase 2 (cIKK2) in airway epithelium. After intratracheal administration of adenoviral vectors expressing cIKK1 or cIKK2 to transgenic reporter mice that express Photinus luciferase under the control of an NF-kappaB-dependent promoter, we detected significantly increased luciferase activity over time (up to 96 h). Compared with control mice treated with adenoviral vectors expressing beta-galactosidase, lung bioluminescence and tissue luciferase activity were increased in NF-kappaB reporter mice treated with adenovirus (Ad)-cIKK1 or Ad-cIKK2. NF-kappaB activation in lungs of Ad-cIKK1- and Ad-cIKK2-treated mice was confirmed by immunoblots for RelA and EMSA from lung nuclear protein extracts. Mice treated with Ad-cIKK1 or Ad-cIKK2 showed induction of mRNA expression of several chemokines and cytokines in lung tissue. In lung lavage fluid, mice treated with Ad-cIKK1 or Ad-cIKK2 showed elevated concentrations of NF-kappaB-dependent chemokines macrophage-inflammatory protein 2 and KC and increased numbers of neutrophils. Coadministration of adenoviral vectors expressing a transdominant inhibitor of NF-kappaB with Ad-cIKK1 or Ad-cIKK2 resulted in abrogated NF-kappaB activation and other parameters of lung inflammation, demonstrating that the observed inflammatory effects of Ad-cIKK1 and Ad-cIKK2 were dependent on NF-kappaB activation by these kinases. These data show that selective expression of IkappaB kinases in airway epithelium results in NF-kappaB activation, inflammatory mediator production, and neutrophilic lung inflammation. Therapies targeted to NF-kappaB in lung epithelium may be beneficial in treating inflammatory lung diseases.
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PMID:Selective I kappa B kinase expression in airway epithelium generates neutrophilic lung inflammation. 1251 78

PTX1 is a gene identified by subtractive hybridization on the basis that it is expressed in normal prostate and not in prostate carcinoma. It encodes a nuclear protein that is downregulated in prostate carcinoma. Expression constructs containing PTX1 cDNA in both sense and antisense orientations were transfected into prostate tumor cell line, PC-3 cells. The effects of the expression of PTX1 and antisense PTX1 on PC-3 cells were examined using cell growth, proliferation, soft agar, invasion chamber, senescence-associated beta-galactosidase, and nude mice assays. Cells transfected with PTX1 construct in the sense orientation were growth-arrested. These cells displayed multiple morphological changes consistent with cellular senescence, including the expression of a senescence-associated beta-galactosidase. On the other hand, expression of antisense PTX1 RNA in PC-3 cells resulted in uncontrolled cell growth and increase of invasive potential. In nude mice, cells expressing antisense PTX1 grew sixfold faster than the control. These results suggest that PTX1 may play an important role in the growth and tumorigenicity of PC-3 cells.
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PMID:Effects of PTX1 expression on growth and tumorigenicity of the prostate cancer cell line PC-3. 1293 5

Plasminogen activator inhibitor type 1 (PAI-1) has been shown to be an independent risk factor for coronary artery disease, myocardial infarction, and cerebrovascular events. Previous studies on variations in plasma PAI-1 levels and associations between PAI-1 levels and PAI-1 genotypes have suggested that PAI-1 expression maybe regulated in a genotype-specific manner by insulin, hypertriglyceridemic very low-density lipoprotein, and lipoprotein. We investigated whether basal transcription of the PAI-1 gene also is regulated in a genotype-specific manner. Allele-specific polymerase chain reaction-amplified fragments containing a 4G/5G polymorphism of the PAI-1 gene promoter were ligated into the chloramphenicol acetyltransferase (CAT) reporter gene. The constructs of p4G-CAT or pSG-CAT and pSV-beta-galactosidase as an internal control were transiently cotransfected into human HepG2 hepatoma cells. Electrophoresis mobility shift assays (EMSA) employed a fragment from positions -687 to -664 (4G allele) or from -688 to -664 (5G allele) labeled with adenosine triphosphate tagged with phosphorous 32 in the gamma position and used nuclear extracts of HepG2 cells. Analysis of CAT produced by constructs containing the PAI-1 4G or 5G allele showed similar 3-fold increases in CAT activity in the PAI-1 4G/4G and PAI-1 5G/5G constructs, compared with the CAT activity in the pCAT3-Basic construct. Analyses using the probes containing the 4G or 5G allele site in the EMSA assay revealed no difference in the binding of nuclear protein. Our in vitro assay of basal transcription suggests no difference in the transcriptional activities of the alleles of the PAI-1 4G/5G polymorphism.
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PMID:No association of the plasminogen activator inhibitor-1 promoter 4G/5G polymorphism with inhibitor level during basal transcription in vitro. 1521 74

Xmi-er1 is a fibroblast growth factor regulated immediate-early gene that is activated during mesoderm induction in Xenopus embryonic explants. This gene encodes a nuclear protein with potent transcriptional regulator activity and overexpression of XMI-ER1 in Xenopus embryos inhibits mesoderm induction and leads to truncations along the anteroposterior axis. We showed previously that XMI-ER1 is retained in the cytoplasm during cleavage stages and only begins to appear in the nucleus at mid-blastula. Such developmentally regulated nuclear translocation may represent an important mechanism for regulating XMI-ER1 activity in the early embryo. Here, we investigate different mechanisms that might control nuclear translocation of XMI-ER1. Using alpha-amanitin to inhibit transcription, we show that nuclear localization is not dependent on zygotic transcription. Nor is it the result of a developmentally regulated import pathway, as the XMI-ER1 nuclear localization signal (NLS) fused to beta-galactosidase (betagal) was able to direct nuclear translocation prior to mid-blastula. Fusion of an additional, heterologous NLS to the N-terminus of XMI-ER1 was not sufficient to overcome cytoplasmic retention, indicating that retention does not involve NLS masking, but rather binding to a cytoplasmic anchor. The anchoring molecule is not an RNA, as microinjection of RNase A did not affect the timing of nuclear translocation. Western blot analysis using antibodies that recognize phosphorylated residues revealed that, while XMI-ER1 is not itself phosphorylated, it is associated with two differentially phosphorylated proteins, suggesting that the anchoring mechanism may involve interaction with a cytoplasmic protein(s). A series of XMI-ER1 deletion mutants was utilized to map the putative retention domain. Our analysis revealed that amino acids 144-175, containing the fourth acidic stretch of the acidic activation domain, are required for retention. These results suggest that XMI-ER1 is retained in the cytoplasm of the early embryo by interaction of the region containing amino acids 144-175 with a cytoplasmic anchor.
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PMID:Developmentally regulated cytoplasmic retention of the transcription factor XMI-ER1 requires sequence in the acidic activation domain. 1547 90


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