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:4.1.1.17 (ornithine decarboxylase)
6,351 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The polyamines are known to be essential for cellular proliferation. Ornithine decarboxylase (ODC) is a rate-limiting enzyme in the synthesis of these amines, and activity is elevated in colorectal tumors and polyps. Two ODC genes (designated ODC1 and ODC2) were localized by somatic cell hybridization and in situ techniques to 2p25 and 7q31-qter, respectively. Investigation of the expression of ODC in colorectal neoplasia reveals a consistent increase in mRNA expression compared with normal adjacent mucosa and control mucosa, ranging from 1.3- to 12.2-fold. No amplification of the loci was seen. Comparison of ODC mRNA expression with ODC activity from the same samples revealed no direct correlation, suggesting that regulation of ODC in this system occurs at the posttranscriptional level.
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PMID:Two chromosomal locations for human ornithine decarboxylase gene sequences and elevated expression in colorectal neoplasia. 197 38

Cells of the ciliated protozoan Tetrahymena thermophila, grown in proteose peptone medium up to late logarithmic phase, harvested by centrifugation, and resuspended in fresh medium to almost the same cell density, underwent one more division cycle within 5 h after inoculation, thereafter being definitely in full stationary phase. This growth cycle proved to be a useful tool to investigate the activation and deactivation of ornithine decarboxylase ODC1 in Tetrahymena: In late logarithmic phase the cells contained a very low specific activity of ODC of about 3 nmol CO2.h-1.mg-1 in the soluble protein fraction. After growth stimulation the activity was increased up to 100-fold within 1 h. This high activity was maintained for about 5 h-about as long as division activity-then rapidly declined with a half life time (t1/2) of about 15 min to the original low level. Inhibition assays with cycloheximide and actinomycin D revealed that: i. the rapid increase of ODC activity was biphasic with one component of translation of preexisting mRNA and one component of translation of newly transcribed mRNA; ii. the t1/2 of the mRNA of ODC was estimated to be about 2 h; iii. inhibition of protein biosynthesis before ODC inactivation at 5 h caused a decrease of ODC with a t1/2 of 55 min instead of 15 min. These findings suggest that ODC activity in Tetrahymena is regulated on both levels: transcription and translation and by an inactivating protein factor which is regulated at the level of biosynthesis.
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PMID:Regulation of ornithine decarboxylase activity in the growth cycle of Tetrahymena thermophila. 225 30

Aging of IMR-90 human diploid fibroblasts in culture is accompanied by specific changes of polyamine metabolism including: (a) a fivefold decrease of serum-induced activity of ornithine decarboxylase (ODC1 EC 4.1.1.17); (b) a six to tenfold increase of polyamine catabolism; and (c) a reduction of putrescine uptake. These changes apparently led to a significant reduction of putrescine accumulation in senescent cells following serum stimulation. Since the induction of ODC is a mid-G1 event, the change of polyamine metabolism may be related to changes of expression of other cell-cycle-dependent genes during cellular aging. In addition to ODC gene, we have examined the expression of two early G1 genes, c-erbB and c-myc, and one late G1/S gene thymidine kinase, at mRNA levels, in both young and old IMR-90 cells. We have also compared the enzyme activities of two late G1/S genes, thymidine kinase and thymidylate synthetase, in young and old cells following serum stimulation. We did not observe significant changes of c-erbB, c-myc, and ODC mRNA levels during cellular senescence. However, we found that serum-induced mRNA level of thymidine kinase gene in old IMR-90 cells was significantly reduced compared to that in the young cells. Results also demonstrate that aging of IMR-90 cells was accompanied by significant decrease of both thymidine kinase and thymidylate synthetase activities. In view of the recognized importance of polyamines in growth regulation, it is possible that alteration of polyamine metabolism may contribute to the impairment of expression of some key G1/S genes and such impairment may contribute to the ultimate loss of dividing potential in senescent cells.
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PMID:Polyamine metabolism and cell-cycle-dependent gene expression in IMR-90 human diploid fibroblasts during senescence in culture. 263 84

The genes for the M2 subunit of ribonucleotide reductase (RRM2), ornithine decarboxylase (ODC1), and 55,000-Daltons protein (P5), are amplified in hydroxyurea-resistant hamster and human cell lines. These genomic sequences have been mapped to hamster chromosome 7 and to human chromosome 2p24-25 near the cytogenetic location of the N-myc gene. We now report that genomic sequences homologous to N-myc are amplified in hydroxyurea-resistant hamster lung cell line, 600H, and the N-myc gene segregates with hamster chromosome 7 in mouse-hamster somatic cell hybrids. The conserved linkage group consisting of the RRM2, ODC1, P5, and N-myc in the hamster and human genomes prompted our investigation of human neuroblastomas. We report here that genomic DNA from 1 of 6 primary neuroblastoma tumors containing amplified N-myc also contains amplified sequences homologous to a hamster ODC cDNA.
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PMID:Amplification of N-myc and ornithine decarboxylase genes in human neuroblastoma and hydroxyurea-resistant hamster cell lines. 278 50

Regulation of ornithine decarboxylase (ODC) is critical to the control of cellular growth, differentiation, and carcinogenesis. A GC-rich region in the ODC promoter contains two overlapping protein binding sites that interact to regulate basal level expression in some cell types. A perfect binding motif for transcription factor Sp1 (CCCCGCCCC) is located at nucleotides -114 to -106 relative to the site of transcriptional initiation, binds strongly to purified Sp1 protein, and forms several complexes when incubated with nuclear extracts. Only one of these complexes is recognized by Sp1-specific antibody. A new protein-binding motif (GCCCCTCCCC, located at -110 to -100) partially overlaps with the Sp1 site and analyses by DNase I protection showed that a new protein ("NF-ODC1") and the Sp1-like proteins interact with the ODC promoter in a mutually exclusive manner. Mutation of the NF-ODC1 binding motif strongly enhanced ODC promoter strength in some cell types, but had little or no influence in others. The effect of mutating the Sp1 site also varied with cell type. These cell type specificities did not correlate with the levels of Sp1 and NF-ODC1 binding activities in nuclear extracts. These results show that regulation of the ODC promoter by the Sp1 family is cell type-specific and modulated by a negative effector that we have termed NF-ODC1.
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PMID:Complex interactions at a GC-rich domain regulate cell type-dependent activity of the ornithine decarboxylase promoter. 813 14

Previous studies have revealed that the MYCN gene spans approximately 7kb, while the amplicon has been estimated to be 100 kb to 1 Mb long [1-3]. This implies that several other genes may be present on the MYCN amplicon. Such co-amplified genes could contribute to the malignant phenotype and might provide an explanation for why not all patients with MYCN amplification have a poor outcome. We investigated 7 neuroblastoma cell lines and 167 primary tumours for the co-amplification of candidate genes known to be present near the MYCN locus: ornithine decarboxylase, ribonucleotide reductase, syndecan-1 and a DEAD box protein gene, DDX1. We also investigated further the pG21 expressed sequence previously reported to be co-amplified with MYCN. No co-amplification with the first 3 genes was found in any of the cell lines or tumour samples. DDX1 was found to be amplified along with MYCN in 4/6 (67%) cell lines and 18/38 (47%) of the MYCN amplified tumours. No amplification of DDX1, ODC1, RRM2 or syndecan-1 was found in the absence of MYCN amplification. DDX1 co-amplification was observed to occur mainly in stage 4 or 4S patients. With the exclusion of those with 4S disease, patients with DDX1 co-amplification had a significantly shorter mean (+/- SE) disease-free interval (4.1 +/- 1.4, n = 8 months) compared with patients with MYCN amplification alone (19.6 +/- 4.5, n = 17) (P = 0.04, Welch's unpaired t-test). The pG21 sequence was identical to part of the DDX1 gene. These observations indicate that there is at least 1 other gene co-amplified with MYCN in a proportion of cases and that those patients with DDX1 co-amplification tend to relapse more quickly. It also implies that the MYCN amplicon is of varied size and/or position relative to the MYCN gene.
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PMID:Analysis of candidate gene co-amplification with MYCN in neuroblastoma. 951 49

Appropriate cellular levels of polyamines are required for cell growth and differentiation. Ornithine decarboxylase is a key regulatory enzyme in the biosynthesis of polyamines, and precise regulation of the expression of this enzyme is required, according to cellular growth state. A variety of mitogens increase the level of ornithine decarboxylase activity, and, in most cases, this elevation is due to increased levels of mRNA. A GC box in the proximal promoter of the ornithine decarboxylase gene is required for basal and induced transcriptional activity, and two proteins, Sp1 and NF-ODC1, bind to this region in a mutually exclusive manner. Using a yeast one-hybrid screening method, ZBP-89, a DNA-binding protein, was identified as a candidate for the protein responsible for NF-ODC1 binding activity. Three lines of evidence verified this identification; ZBP-89 copurified with NF-ODC1 binding activity, ZBP-89 antibodies specifically abolished NF-ODC1 binding to the GC box, and binding affinities of 12 different double-stranded oligonucleotides were indistinguishable between NF-ODC1, in nuclear extract, and in vitro translated ZBP-89. ZBP-89 inhibited the activation of the ornithine decarboxylase promoter by Sp1 in Schneider's Drosophila line 2, consistent with properties previously attributed to NF-ODC1.
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PMID:Transcription factor ZBP-89 regulates the activity of the ornithine decarboxylase promoter. 968 30

We investigated the antiviral activity of olive leaf extract (OLE) preparations standardized by liquid chromatography-coupled mass spectrometry (LC-MS) against HIV-1 infection and replication. We find that OLE inhibits acute infection and cell-to-cell transmission of HIV-1 as assayed by syncytia formation using uninfected MT2 cells co-cultured with HIV-1-infected H9 T lymphocytes. OLE also inhibits HIV-1 replication as assayed by p24 expression in infected H9 cells. These anti-HIV effects of OLE are dose dependent, with EC(50)s of around 0.2 microg/ml. In the effective dose range, no cytotoxicity on uninfected target cells was detected. The therapeutic index of OLE is above 5000. To identify viral and host targets for OLE, we characterized gene expression profiles associated with HIV-1 infection and OLE treatment using cDNA microarrays. HIV-1 infection modulates the expression patterns of cellular genes involved in apoptosis, stress, cytokine, protein kinase C, and hedgehog signaling. HIV-1 infection up-regulates the expression of the heat-shock proteins hsp27 and hsp90, the DNA damage inducible transcript 1 gadd45, the p53-binding protein mdm2, and the hedgehog signal protein patched 1, while it down-regulates the expression of the anti-apoptotic BCL2-associated X protein Bax. Treatment with OLE reverses many of these HIV-1 infection-associated changes. Treatment of HIV-1-infected cells with OLE also up-regulates the expression of the apoptosis inhibitor proteins IAP1 and 2, as well as the calcium and protein kinase C pathway signaling molecules IL-2, IL-2Ralpha, and ornithine decarboxylase ODC1.
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PMID:Anti-HIV activity of olive leaf extract (OLE) and modulation of host cell gene expression by HIV-1 infection and OLE treatment. 1287 15

A gene encoding putative ornithine decarboxylase (ODC) has been isolated by differential screening of a cDNA library from the resistant hot pepper (Capsicum annuum L.) inoculated with avirulent tobacco mosaic virus (TMV) pathotype P0. In hot pepper plants, transcripts of the CaODC1 (C. annuum ODC1) gene started to accumulate at 24 h post-inoculation of TMV-P0 and the signal was spread systemically. The transcript level of CaODC1 was increased rapidly in a hot pepper resistant to Xanthomonas campestris pv. vesicatoria (Xcv) but not in a susceptible hot pepper after inoculation. These results suggest possible role(s) for CaODC1 in plant defense against a broad range of pathogens including viruses and bacteria.
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PMID:Ornithine decarboxylase gene (CaODC1) is specifically induced during TMV-mediated but salicylate-independent resistant response in hot pepper. 2400 54

Enterovirus 71 (EV71) is a major etiological agent of hand, foot and mouth disease (HFMD). Several outbreaks in East Asia were associated with neurological complications and numerous deaths. EV71 possesses four structural proteins VP1-VP4 that are necessary in the formation of the pentameric icosahedral capsid. The viral capsid contributes to virulence, and VP1 is a prime target for EV71 vaccine development. Using yeast two-hybrid analysis, we demonstrated binding affinity between VP1 and three human proteins, i.e. ornithine decarboxylase (ODC1), gene trap ankyrin repeat (GTAR), and KIAA0697 expressed in brain tissue. These interactions were authenticated by co-immunoprecipitation experiments, and by indirect immunofluorescent confocal microscopy of transfected and EV71-infected Vero cells. The significant interaction between VP1 and ODC1 may compromise the latter's activity, and interfere with polyamine biosynthesis, growth and proliferation of EV71-infected cells. The interaction between VP1 and GTAR is noteworthy, since ankyrin proteins are associated with certain neural cell adhesion molecules and with the CRASH neurological syndrome. Given that VP1 is synthesized in large amounts during productive infection, these viral-host protein interactions may provide insights into the role of VP1 in the pathogenesis of EV71 disease and its neurological complications such as acute flaccid paralysis and encephalitis.
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PMID:The VP1 structural protein of enterovirus 71 interacts with human ornithine decarboxylase and gene trap ankyrin repeat. 1727 51


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