Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Dent's disease is an X-linked renal tubular disorder characterized by low-molecular-weight proteinuria, hypercalciuria, nephrocalcinosis, nephrolithiasis, and renal failure. Patients with Dent's disease may also suffer from rickets and other features of the renal Fanconi Syndrome. Patients may have mutations in the X-linked renal chloride channel gene, CLCN5, which encodes a 746-amino-acid protein with 12-13 transmembrane domains. We have investigated the 11 coding exons of CLCN5 for mutations in eight unrelated patients with Dent's disease. Leukocyte DNA was used for the polymerase chain reaction amplification of CLCN5 and the products analyzed for single-stranded conformational polymorphisms (SSCPs). Abnormal SSCPs were sequenced and revealed eight mutations. These consisted of three nonsense mutations (Arg34Stop, Arg648Stop, Arg704Stop), four deletions involving codons 40, 86, 157, and 241, and one acceptor splice consensus sequence mutation tgcag --> tgaag. The mutations were confirmed either by restriction endonuclease or sequence-specific oligonucleotide hybridization analysis. In addition, an analysis of 110 alleles from 74 unrelated normal individuals demonstrated that the DNA sequence changes were not common polymorphisms. All of the mutations predict truncated chloride channels that are likely to result in a functional loss. Thus, our findings expand the spectrum of CLCN5 mutations associated with Dent's disease and the results will help to elucidate further the functional domains of this novel chloride channel.
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PMID:Renal chloride channel, CLCN5, mutations in Dent's disease. 1046 81

Dent's disease is an X-linked renal tubular disorder characterized by low molecular weight proteinuria, hypercalciuria, nephrocalcinosis, nephrolithiasis, and renal failure. The disease is caused by mutations in a renal chloride channel gene, CLCN5, which encodes a 746 amino acid protein (CLC-5), with 12 to 13 transmembrane domains. In this study, an additional six unrelated patients with Dent's disease were identified and investigated for CLCN5 mutations by DNA sequence analysis of the 11 coding exons of CLCN5. This revealed six mutations: four frameshift deletions involving codons 392, 394, 658, and 728, one nonsense mutation (Tyr617Stop), and an A to T transversion at codon 601 that would result in either a missense mutation (Asp601Val) or creation of a novel donor splice site. These mutations were confirmed by restriction endonuclease or sequence-specific oligonucleotide hybridization analysis and were not common polymorphisms. The frameshift deletions and nonsense mutation predict truncated and inactivated CLC-5. The effects of the putative missense Asp601Val mutant CLC-5 were assessed by heterologous expression in Xenopus oocytes, and this revealed a chloride conductance that was similar to that observed for wild-type CLC-5. However, an analysis of the mutant CLCN5 transcripts revealed utilization of the novel donor splice site, resulting in a truncated CLC-5. Thus, all of the six mutations are likely to result in truncated CLC-5 and a loss of function, and these findings expand the spectrum of CLCN5 mutations associated with Dent's disease.
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PMID:Characterization of renal chloride channel (CLCN5) mutations in Dent's disease. 1090 59

Renal cell carcinoma is the most common neoplasm occurring in the kidney and is largely resistant to current chemotherapy. Understanding the mechanisms involved in renal carcinoma cell death may lead to novel and more effective therapies. In Cak(i)-1 renal cancer cells, using phosphatidylserine externalization as a marker of apoptosis, the anti-cancer drugs 5-fluorouracil (5-FU), and its pro-drugs, doxifluridine (Dox) and floxuridine (Flox) proceeds via a caspase-dependent mechanism. In contrast, phosphatidylserine externalization produced by staurosporine in the renal cancer cell lines Cak(i)-1 and A-498 proceeds via a caspase-independent mechanism. That is, the pan caspase inhibitor N-benzyloxycabonyl-Val-Ala-Asp-fluoromethylketone (ZVAD) did not ameliorate annexin V binding, cell shrinkage or changes in nuclear morphology. Subsequent experiments were conducted to determine mediators of phosphatidylserine externalization, using annexin V binding, when caspases were inhibited. Prior treatment of A-498 cells with cathepsin B (CA74 methyl ester), cathespsin D (pepstatin A) or calpain inhibitors (calpeptin, E64d) in the presence or absence of ZVAD did not ameliorate annexin V binding. The endonuclease inhibitor aurintricarboxylic acid (ATA), phospholipase A(2) inhibitor bromoenol lactone (BEL), protein synthesis inhibitor cycloheximide (CH) and chloride channel blockers niflumic acid (NFA) and 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB) all had no effect on staurosporine-induced annexin V binding in A-498 cells either in the presence or absence of ZVAD. We also modulated sphingomyelin and the de novo pathways of ceramide synthesis and found no amelioration of staurosporine-induced annexin V binding in A-498 cells either in the presence or absence of ZVAD. These results indicate that 5-FU, Dox and Flox induce externalization of phosphatidylserine during apoptosis in Cak(i)-1 renal cancer cells primarily through a caspase-dependent mechanism and that externalization of phosphatidylserine during apoptosis produced by staurosporine in the renal cancer cell line A-498 is independent of many of the common signaling pathways known to be involved in this process.
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PMID:Caspase-dependent and -independent induction of phosphatidylserine externalization during apoptosis in human renal carcinoma Cak(1)-1 and A-498 cells. 1709 91