Infrequent and rare genetic variants in the human population vastly outnumber common ones. Although they may contribute significantly to the genetic basis of a disease, these seldom-encountered variants may also be miss-identified as pathogenic if no correct references are available. Somatic and germline TP53 variants are associated with multiple neoplastic diseases, and thus have come to serve as a paradigm for genetic analyses in this setting. We searched 14 independent, globally distributed datasets and recovered TP53 SNPs from 202,767 cancer-free individuals. In our analyses, 19 new missense TP53 SNPs, including five novel variants specific to the Asian population, were recurrently identified in multiple datasets. Using a combination of in silico, functional, structural, and genetic approaches, we showed that none of these variants displayed loss of function compared to the normal TP53 gene. In addition, classification using ACMG criteria suggested that they are all benign. Considered together, our data reveal that the TP53 coding region shows far more polymorphism than previously thought and present high ethnic diversity. They furthermore underline the importance of correctly assessing novel variants in all variant-calling pipelines associated with genetic diagnoses for cancer.

• MeSH
• geny p53 genetika   MeSH
• jednonukleotidový polymorfismus genetika   MeSH
• lidé MeSH
• missense mutace genetika   MeSH
• nádorový supresorový protein p53 genetika   MeSH
• nádory genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• nádorový supresorový protein p53 MeSH

Glioblastoma is the most common and the most aggressive type of brain cancer. Aberrations of the RTK/RAS/PI3K-, p53-, and RB cell signaling pathways were recognized as a core requirement for pathogenesis of glioblastoma. The p53 tumor suppressor functions as a transcription factor transactivating expression of its target genes in response to various stress stimuli. We determined the p53 status in 36 samples of glioblastoma by functional analyses FASAY and split assay. Seventeen p53 mutations were detected and further analyzed by cDNA and gDNA sequencing in 17 patients (47.2 %). Fifteen (88.2 %) of the mutations were missense mutations causing amino acid substitutions, seven of them exhibited temperature-sensitivity. Two mutations were determined as short deletions, one of them causing formation of premature termination codon in position 247. Fluorescent in situ hybridization revealed the loss of the p53-specific 17p13.3 locus in four of 33 analyzed samples (12 %). In 12 out of 30 samples (40 %), the p53 protein accumulation was shown by immunoblotting. There was high (80 %) concordance between the presence of the clonal p53 mutation and the p53 protein accumulation.

• MeSH
• delece genu MeSH
• geny p53 * MeSH
• glioblastom genetika   metabolismus   MeSH
• hybridizace in situ fluorescenční MeSH
• kvasinky MeSH
• lidé středního věku MeSH
• lidé MeSH
• mutace * MeSH
• mutační analýza DNA MeSH
• nádorové buněčné linie MeSH
• nádorový supresorový protein p53 genetika   metabolismus   MeSH
• nádory mozku genetika   metabolismus   MeSH
• orgánová specificita MeSH
• sekvenční analýza DNA MeSH
• senioři MeSH
• teplota MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• nádorový supresorový protein p53 MeSH
• TP53 protein, human MeSH Prohlížeč

Hot spot mutant p53 (mutp53) proteins exert oncogenic gain-of-function activities. Binding of mutp53 to DNA is assumed to be involved in mutp53-mediated repression or activation of several mutp53 target genes. To investigate the importance of DNA topology on mutp53-DNA recognition in vitro and in cells, we analyzed the interaction of seven hot spot mutp53 proteins with topologically different DNA substrates (supercoiled, linear and relaxed) containing and/or lacking mutp53 binding sites (mutp53BS) using a variety of electrophoresis and immunoprecipitation based techniques. All seven hot spot mutp53 proteins (R175H, G245S, R248W, R249S, R273C, R273H and R282W) were found to have retained the ability of wild-type p53 to preferentially bind circular DNA at native negative superhelix density, while linear or relaxed circular DNA was a poor substrate. The preference of mutp53 proteins for supercoiled DNA (supercoil-selective binding) was further substantiated by competition experiments with linear DNA or relaxed DNA in vitro and ex vivo. Using chromatin immunoprecipitation, the preferential binding of mutp53 to a sc mutp53BS was detected also in cells. Furthermore, we have shown by luciferase reporter assay that the DNA topology influences p53 regulation of BAX and MSP/MST1 promoters. Possible modes of mutp53 binding to topologically constrained DNA substrates and their biological consequences are discussed.

• MeSH
• intracelulární signální peptidy a proteiny MeSH
• lidé MeSH
• mutace * MeSH
• mutantní proteiny chemie   genetika   metabolismus   MeSH
• nádorové buněčné linie MeSH
• nádorový supresorový protein p53 chemie   genetika   metabolismus   MeSH
• plazmidy genetika   MeSH
• promotorové oblasti (genetika) genetika   MeSH
• protein X asociovaný s bcl-2 genetika   MeSH
• protein-serin-threoninkinasy genetika   MeSH
• regulace genové exprese genetika   MeSH
• substrátová specifita MeSH
• superhelikální DNA chemie   metabolismus   MeSH
• vazba proteinů MeSH
• vazebná místa MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• intracelulární signální peptidy a proteiny MeSH
• mutantní proteiny MeSH
• nádorový supresorový protein p53 MeSH
• protein X asociovaný s bcl-2 MeSH
• protein-serin-threoninkinasy MeSH
• STK4 protein, human MeSH Prohlížeč
• superhelikální DNA MeSH