Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.27.1 (RNase)
 16,360 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The objective of this study was to provide more accurate frequency estimates of breast cancer susceptibility gene 1 ( BRCA1 ) germline alterations in the ovarian cancer population. To achieve this, we determined the prevalence of BRCA1 alterations in a population-based series of consecutive ovarian cancer cases. This is the first population-based ovarian cancer study reporting BRCA1 alterations derived from a comprehensive screen of the entire coding region. One hundred and seven ovarian cancer cases were analyzed for BRCA1 alterations using the RNase mismatch cleavage assay followed by direct sequencing. Two truncating mutations, 962del4 and 3600del11, were identified. Both patients had a family history of breast or ovarian cancer. Several novel as well as previously reported uncharacterized variants were also identified, some of which were associated with a family history of cancer. The frequency distribution of common polymorphisms was determined in the 91 Caucasian cancer cases in this series and 24 sister controls using allele-specific amplification. The rare form of the Q356R polymorphism was significantly ( P = 0.03) associated with a family history of ovarian cancer, suggesting that this polymorphism may influence ovarian cancer risk. In summary, our data suggest a role for some uncharacterized variants and rare forms of polymorphisms in determining ovarian cancer risk, and highlight the necessity to screen for missense alterations as well as truncating mutations in this population.
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PMID:Germline BRCA1 alterations in a population-based series of ovarian cancer cases. 1019 79

Disrupting the function of the BRCA1 gene by mechanisms other than germline mutations is suspected to occur in cases of sporadic breast/ovarian cancers. Using ribonuclease protection assay and multiplex RT-PCR, we examined the change of the total BRCA1 mRNA pool and the expression profile of four predominant BRCA1 splice variants in asynchronous and in G1/S synchronized tumor cell populations compared to normal breast cells. Experiments were carried out on MCF-7 and MDA-MB-231 breast cancer, OVCAR-5 ovarian cancer, and K562 leukemia cell lines. The ratio of the full length, the delta(11q), the delta(9,10), and the delta(9,10,11q) BRCA1 isoforms showed different expression patterns in the examined breast and ovarian tumor cell lines as compared to the leukemia cell line. This observation raises the possibility that the dysregulation of alternative splicing of the BRCA1 gene could be involved in tumor formation in the breast and the ovary, even in the absence of germline mutations.
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PMID:Expression profiles of BRCA1 splice variants in asynchronous and in G1/S synchronized tumor cell lines. 1116 73

Regulation, recognition and cell signaling involve the coordinated actions of many players. Signaling scaffolds, with their ability to bring together proteins belonging to common and/or interlinked pathways, play crucial roles in orchestrating numerous events by coordinating specific interactions among signaling proteins. This review examines the roles of intrinsic disorder (ID) in signaling scaffold protein function. Several well-characterized scaffold proteins with structurally and functionally characterized ID regions are used here to illustrate the importance of ID for scaffolding function. These examples include scaffolds that are mostly disordered, only partially disordered or those in which the ID resides in a scaffold partner. Specific scaffolds discussed include RNase, voltage-activated potassium channels, axin, BRCA1, GSK-3beta, p53, Ste5, titin, Fus3, BRCA1, MAP2, D-AKAP2 and AKAP250. Among the mechanisms discussed are: molecular recognition features, fly-casting, ease of encounter complex formation, structural isolation of partners, modulation of interactions between bound partners, masking of intramolecular interaction sites, maximized interaction surface per residue, toleration of high evolutionary rates, binding site overlap, allosteric modification, palindromic binding, reduced constraints for alternative splicing, efficient regulation via posttranslational modification, efficient regulation via rapid degradation, protection of normally solvent-exposed sites, enhancing the plasticity of interaction and molecular crowding. We conclude that ID can enhance scaffold function by a diverse array of mechanisms. In other words, scaffold proteins utilize several ID-facilitated mechanisms to enhance function, and by doing so, get more functionality from less structure.
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PMID:Intrinsic disorder in scaffold proteins: getting more from less. 1861 97

BRCA1 is a tumor suppressor gene that is mutated in families with breast and ovarian cancer. Several BRCA1 splice variants are found in different tissues, but their subcellular localization and functions are poorly understood at the moment. We previously described BRCA1 splice variant BRCA1a to induce apoptosis and function as a tumor suppressor of triple negative breast, ovarian and prostate cancers. In this study we have analyzed the function of BRCA1 isoforms (BRCA1a and BRCA1b) and compared them to the wild-type BRCA1 protein using several criteria like studying expression in normal and tumor cells by RNase protection assays, subcellular localization/fractionation by immunofluorescence microscopy and Western blot analysis, transcription regulation of biological relevant proteins and growth suppression in breast cancer cells. We are demonstrating for the first time that ectopically expressed GFP-tagged BRCA1, BRCA1a, and BRCA1b proteins are localized to the mitochondria, repress ELK-1 transcriptional activity and possess antiproliferative activity on breast cancer cells. These results suggest that the exon 9, 10, and 11 sequences (aa 263-1365) which contain two nuclear localization signals, p53, Rb, c-Myc, gamma-tubulin, Stat, Rad51, Rad50 binding domains, angiopoietin-1 repression domain are not absolutely required for mitochondrial localization and growth suppressor function of these proteins. Since mitochondrial dysfunction is a hallmark of cancer, we can speculate that the mitochondrial localization of BRCA1 proteins may be functionally significant in regulating both the mitochondrial DNA damage as well as apoptotic activity of BRCA1 proteins and mislocalization causes cancer. J. Cell. Physiol. 219: 634-641, 2009. (c) 2009 Wiley-Liss, Inc.
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PMID:Mitochondrial localization, ELK-1 transcriptional regulation and growth inhibitory functions of BRCA1, BRCA1a, and BRCA1b proteins. 1917 Jan 8

DNA double-strand breaks (DSBs) are toxic DNA lesions, which, if not properly repaired, may lead to genomic instability, cell death and senescence. Damage-induced long non-coding RNAs (dilncRNAs) are transcribed from broken DNA ends and contribute to DNA damage response (DDR) signaling. Here we show that dilncRNAs play a role in DSB repair by homologous recombination (HR) by contributing to the recruitment of the HR proteins BRCA1, BRCA2, and RAD51, without affecting DNA-end resection. In S/G2-phase cells, dilncRNAs pair to the resected DNA ends and form DNA:RNA hybrids, which are recognized by BRCA1. We also show that BRCA2 directly interacts with RNase H2, mediates its localization to DSBs in the S/G2 cell-cycle phase, and controls DNA:RNA hybrid levels at DSBs. These results demonstrate that regulated DNA:RNA hybrid levels at DSBs contribute to HR-mediated repair.
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PMID:BRCA2 controls DNA:RNA hybrid level at DSBs by mediating RNase H2 recruitment. 3056 Sep 44