Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.69 (APC)
 16,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Protein C is a vitamin K-dependent zymogen of a serine protease that inhibits blood coagulation by the proteolytic inactivation of factors Va and VIIIa. Individuals affected with protein C deficiency are at risk for thrombosis. Genetic analyses of affected individuals, to determine the cause of the protein C deficiency, revealed a large variety of mutations in the protein C gene, including several in the promoter region of this gene. Comparison of the region around two of these mutations, A-32-->G and T-27-->A, with transcription factor consensus sequences suggested the presence of two overlapping and inversely oriented HNF-3 binding sites. Direct evidence for the presence of the two HNF-3 binding sites in the protein C promoter was obtained using electrophoretic mobility shift assays and UV cross-linking experiments. These experiments revealed that HNF-3 can bind specifically to both putative HNF-3 sites in the wild-type protein C promoter. Due to the T-27-->A mutation, one binding site is completely lost, while the other site still binds HNF-3, but with strongly reduced affinity. As a consequence of the A-32-->G mutation, the protein C promoter loses all its HNF-3 binding capacity. Transient transfection experiments demonstrated that the binding of HNF-3 to the protein C promoter is of physiological significance. This followed from experiments in which the introduction of the A-32-->G or T-27-->A mutation resulted in a 4-5-fold reduced promoter activity in HepG2 cells. Furthermore, transactivation of the wild-type protein C promoter construct with HNF-3 showed a 4-5-fold increased promoter activity in HepG2 cells. In HeLa cells, significant wild-type promoter activity was only observed after transactivation with HNF-3. When a promoter construct containing the T-->A mutation at position -27 was used, the transactivation potential of HNF-3 was 2-fold reduced in HepG2 cells, whereas in HeLa cells no transactivation was observed. With the promoter construct containing the A-32-->G mutation, no transactivation by HNF-3 was found either in HepG2 or in HeLa cells.
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PMID:Two mutations in the promoter region of the human protein C gene both cause type I protein C deficiency by disruption of two HNF-3 binding sites. 759 27

Human protein C is a liver-produced plasma anticoagulant. Four heterozygous point mutations located in the promoter region have been identified in families with type I protein C deficiency and recurrent venous thrombosis. However, detailed analysis of regulatory elements and their interacting factors remains to be undertaken. This report presents results of biochemical and functional characterizations of several cis-elements located in the 5'-upstream regulatory region and the trans-acting factors that interact with them. A cloned DNA fragment from nucleotides (nt) -418 to +45 could confer tissue specificity, whereas nt -88 to +45 was sufficient for basal promoter activity of protein C gene. Five cis-elements corresponding to HNF-1, HNF-3, and NF-I/CTF binding sites have been identified. Four heterozygous mutations have been shown to disrupt HNF-3 [mutants of A(-32)G and T(-27)A] and HNF-1 [T(-14)C and C(-10)T] binding. Mutation in the NF-I-binding site also significantly impairs the promoter activity. Viewed as a whole, these results indicate that HNF-1, HNF-3, and NF-I/CTF play critical roles in transcriptional regulation of the protein C gene.
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PMID:Characterization of human protein C gene promoter: insights from natural human mutants. 894 31

We have previously characterized the functional cis elements of the protein C promoter. One hepatocyte nuclear factor-1 (HNF-1) site, three HNF-3 sites, and at least two NF-I sites have been identified within the 140-bp basal transcriptional unit of this promoter. Here we present evidence that either HNF-1alpha or HNF-3 can cooperate with each other in binding to their cis elements. The results from the co-transfection assays in HeLa cells showed a novel synergistic transactivation between HNF-1alpha and HNF-3. Our data further indicate that the unique overlapping of the HNF-3 sites, the specific spatial relationship of the sites, and the co-activator C/EBP all contributed to the synergistic interaction. Although NF-I itself has a weak transactivating effect, it apparently coordinates the transactivation complex formation. NF-I can synergistically enhance the transactivation of HNF-1alpha or HNF-3. Taken together, the combinatorial interplay of HNF-1alpha, HNF-3, and NF-I make a significant contribution to the activation of the liver-specific protein C gene.
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PMID:Synergistic transactivation of HNF-1alpha, HNF-3, and NF-I contributes to the activation of the liver-specific protein C gene. 917 62

Recent studies on human protein C gene expression have revealed the presence of three transcription factor binding sites in close proximity to the transcription start site. Binding sites for the liver-enriched hepatocyte nuclear factors 1 and 3 (HNF-1 and HNF-3, respectively) are located immediately upstream of the transcription start site, whereas just downstream of the start site a presently unidentified transcription factor may bind. To identify other candidate transcription factor binding sites in the protein C promoter, we studied the promoter sequence identity in a number of evolutionarily close and more distant species: Gorilla gorilla, Pongo pygmaeus, Pan troglodytes, Homo sapiens, Cebus apella, Macaca mulatta, Callithrix jacchus, Papio hamadryas, Macaca fascicularis, and Rattus norvegicus. This analysis showed that a high degree of identity (78%) exists among the different primates. Comparison of the primate consensus sequence with the Rattus norvegicus protein C promoter sequence revealed the presence of seven identical regions (I to VII). Two of these regions overlap with established regulatory sequences for HNF-3 and HNF-1 (region VI) and for PCE-1 (region VII), respectively. The functional importance and the transcription factors that may bind to the other five identical regions are now to be determined.
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PMID:Identification of evolutionarily invariant sequences in the protein C gene promoter. 984 7

Recent studies on the regulation of protein C gene transcription revealed the presence of three transcription-factor binding sites in the close proximity to the transcription start site. The proximal 40 bp upstream of the transcription-initiation site contain two, partly overlapping, binding sites for the liver-enriched hepatocyte nuclear factor (HNF)-3 and one binding site to which HNF-1 and HNF-6 bind in a mutually exclusive manner. In order to examine the functionality of the tight alignment of transcription-factor binding sites around the transcription-initiation site, we performed insertional mutagenesis experiments. Sequences were inserted at position -21, separating both HNF-3 binding sites from the HNF-1-HNF-6 binding site, and position -5, separating the HNF-3-HNF-1-HNF-6 complex from the transcription start site. All insertions were made in the context of the protein C gene -386/+107 promoter region and tested for activity by transient transfection experiments. Insertions at position -21 resulted in a combined distance- and DNA-turn-dependent increase in protein C gene expression. Insertions of variable length at position -5 decreased protein C gene expression in a DNA-turn-dependent manner. However, this turn-dependent decrease was accompanied by a distance-dependent increase in promoter activity. This is the first report in which changing the spacing between adjacent transcription-factor binding sites results in enhanced transcription, indicating the submaximal alignment of promoter elements in the wild-type protein C gene promoter region.
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PMID:Unique distance- and DNA-turn-dependent interactions in the human protein C gene promoter confer submaximal transcriptional activity. 1033 97

Severe protein C deficiency is a rare, early onset, venous thrombotic condition that is inherited as an autosomal recessive trait. The protein C (PROC) genes of nine unrelated individuals with severe protein C deficiency were sequenced yielding a total of 13 different lesions. Eight of these were novel, including a gross gene deletion, three missense mutations, two micro-deletions, a splicing mutation and a single base-pair substitution in the HNF-3 binding site in the PROC gene promoter. Evidence for the pathogenicity of the mutations detected was obtained by molecular modelling, in vitro splicing assay and reporter gene assay. Neither the plasma protein C activity level nor the nature of the PROC gene lesions detected were found to be a good prognostic indicator of the age of onset or clinical severity of thrombotic symptoms. Other factors may thus complicate the relationship between genotype and clinical phenotype. Indeed, in two patients, the inheritance of either one or two Factor V Leiden alleles in addition to two PROC gene lesions could have served to precipitate the thrombotic events. No association was however apparent between clinical severity and the possession of a particular promoter polymorphism genotype. Despite the absence of a clear genotype-phenotype relationship, the molecular genetic analysis of the severe recessive form of protein C deficiency potentiates both the counselling of affected families and the provision of antenatal exclusion diagnosis.
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PMID:Molecular genetic analysis of severe protein C deficiency. 1094 14

Sclerosing hemangioma (PSH) is a rare pulmonary tumor, in which two types of tumor cells could be histologically discerned--surface and stromal tumor cells. Nine tumor-tissue specimens from six female Japanese patients were studied, focusing on the distribution of several transcription factors related to lung epithelial development and surfactant proteins and comparing the ultrastructural features of the tumor cells. The immunohistochemical analysis revealed that the surfactant proteins of surfactant apoprotein A, surfactant protein B, and prosurfactant protein C were distributed in many of the surface-lining cells and in a small number of stromal-tumor cells. In addition, the nuclei of the tumor cells stained positive for thyroid transcription factor 1 (TTF)-1, hepatocyte nuclear factor (HNF)-3 alpha, and HNF-3 beta. In situ hybridization staining for TTF-1 showed similar positive signals. Ultrastructurally, two types of tumor cells showed similar features, but stromal tumor cells lost the definitive apico-lateral differentiation compared with the surface tumor cells and showed restricted surface differentiation between the adjacent tumor cells, forming small lumina accompanied by microvilli and occasional multi-vesicle or multi-lamellar bodies. Conclusively, the real tumoral population being undifferentiated stromal cells, the lining cells are fully differentiated type-II pneumonocytes. PSH is a proliferation of rather fetal type-II pneumonocytes (pneumocytoma or pneumoblastoma?).
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PMID:Type-II pneumocyte differentiation in pulmonary sclerosing hemangioma: ultrastructural differentiation and immunohistochemical distribution of lineage-specific transcription factors (TTF-1, HNF-3 alpha, and HNF-3 beta) and surfactant proteins. 1513 14

The forkhead box M1 (FoxM1) transcription factor is overexpressed in many cancers, and in mouse models it is required for tumor progression. FoxM1 activates expression of the cell cycle genes required for both S and M phase progression. Here we demonstrate that FoxM1 is degraded in late mitosis and early G(1) phase by the anaphase-promoting complex/cyclosome (APC/C) E3 ubiquitin ligase. FoxM1 interacts with the APC/C complex and its adaptor, Cdh1. Expression of Cdh1 stimulated degradation of the FoxM1 protein, and depletion of Cdh1 resulted in stabilization of the FoxM1 protein in late mitosis and in early G(1) phase of the cell cycle. Cdh1 has been implicated in regulating S phase entry. We show that codepletion of FoxM1 inhibits early S phase entry observed in Cdh1-depleted cells. The N-terminal region of FoxM1 contains both destruction box (D box) and KEN box sequences that are required for targeting by Cdh1. Mutation of either the D box sequence or the KEN box sequence stabilized FoxM1 and blocked Cdh1-induced proteolysis. Cells expressing a nondegradable form of FoxM1 entered S phase rapidly following release from M phase arrest. Together, our observations show that FoxM1 is one of the targets of Cdh1 in late M or early G(1) phase and that its proteolysis is important for regulated entry into S phase.
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PMID:Anaphase-promoting complex/cyclosome-CDH1-mediated proteolysis of the forkhead box M1 transcription factor is critical for regulated entry into S phase. 1857 89