Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P43146 (tumour suppressor)
 5,935 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This report describes a simple and efficient system for construction of recombinant pseudorabies (Aujeszky's disease) virus (PrV) which is based on the use of a unique restriction site inserted into the viral genome. This system enables the recovery of genetically modified viruses without screening or selection for a specific phenotype, since practically all mature viral particles obtained carry the foreign sequences. To demonstrate, we introduced the tumour suppressor protein-53 (p53) gene into two different intergenic locations of PrV: the ribonucleotide reductase (rr) gene and the promoter of a putative latency gene (PLAT), located at the inverted repeat (IR) region of the viral genome. As a first step, we engineered a unique EcoRI recognition site into the rr gene or into both copies of PLAT with the help of marker transfer using the bacterial lacZ gene. Then, in both cases viral DNAs were cut with the restriction endonuclease EcoRI followed by treatment with calf intestinal phosphatase and used for cotransfection into porcine kidney cells with a plasmid containing the p53 gene flanked by viral DNAs homologous to the target region. As a result of this process, in most of the experiments, we obtained recombinant viruses without the background of parental viruses. Here we show that this method can be used for directional insertion of exogenous sequences into either the unique or the IR region of the PrV chromosome. In principle, this system should be applicable to the construction of recombinant derivatives of any viruses having infectious DNA.
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PMID:A restriction cleavage and transfection system for introducing foreign DNA sequences into the genome of a herpesvirus. 960 3

We have studied hypoxia-induced cell cycle arrest in human cells where the retinoblastoma tumour suppressor protein (pRb) is either functional (T-47D and T-47DHU-res cells) or abrogated by expression of the HPV18 E7 oncoprotein (NHIK 3025 cells). We have previously found that pRb is dephosphorylated and rebound in the nucleus in T-47D cells arrested in S-phase during hypoxia and that this binding is protracted even following re-oxygenation. In the present study, however, we show that the long-lasting arrest following re-oxygenation induced by pRb-binding in the cell nuclei may be overruled by an elevated level of ribonucleotide reductase (RNR). This seems to create a forced DNA-synthesis, uncoordinated with cell division, which induces endoreduplication of the DNA. The data indicate that the cells initiating endoreduplication continue DNA-synthesis until all DNA is replicated once and then may start cycling and cell division with a doubled DNA-content. Corresponding data on the pRb-incompetent NHIK 3025-cells show similar endoreduplication in these. Thus, the data indicate that endoreduplication of DNA following re-oxygenation may come, either as a result of hypoxic arrest of DNA-synthesis when pRb-function is absent in the cells, or if it is overruled by increased RNR. The present study further shows that pRb not only protects the culture by arresting most of the cells that are exposed to extreme hypoxia in S-phase, but also increases cell survival by means of increased clonogenic ability of these cells. Interestingly, however, cells having an elevated level of RNR have equally high survival as wild-type cells following 20 h extreme hypoxia. If RNR-overruling of pRb-mediated arrest following re-oxygenation results in an unstable genome, this may therefore represent a danger of oncogenic selection as the protective effect of pRb on cell survival seems to be maintained.
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PMID:Counteraction of pRb-dependent protection after extreme hypoxia by elevated ribonucleotide reductase. 1537 35

The tumour suppressor protein p53 is a critical component of cell cycle checkpoint responses. It upregulates the expression of cyclin-dependent kinase inhibitors in response to DNA damage and other cellular perturbations, and promotes apoptosis when DNA repair pathways are overwhelmed. Given the high incidence of p53 mutations in human cancers, it has been extensively studied, though only a small fraction of these investigations have been in non-mammalian systems. For the present study, an anti-rainbow trout p53 polyclonal antibody was generated. A variety of rainbow trout (Oncorhynchus mykiss) tissues and cell lines were examined through western blot analysis of cellular protein extracts, which revealed relatively high p53 levels in brain and gills. To evaluate the checkpoint response of rainbow trout p53, RTbrain-W1 and RTgill-W1 cell lines were exposed to varying concentrations of the DNA damaging agent bleomycin and ribonucleotide reductase inhibitor hydroxyurea. In contrast to mammals, these checkpoint-inducing agents provoked no apparent increase in rainbow trout p53 levels. These results infer the presence of alternate DNA damage checkpoint mechanisms in rainbow trout cells.
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PMID:Characterization of p53 expression in rainbow trout. 2176 62

Oncogene-evoked replication stress (RS) fuels genomic instability in diverse cancer types. Here we report that BRCA1, traditionally regarded a tumour suppressor, plays an unexpected tumour-promoting role in glioblastoma (GBM), safeguarding a protective response to supraphysiological RS levels. Higher BRCA1 positivity is associated with shorter survival of glioma patients and the abrogation of BRCA1 function in GBM enhances RS, DNA damage (DD) accumulation and impairs tumour growth. Mechanistically, we identify a novel role of BRCA1 as a transcriptional co-activator of RRM2 (catalytic subunit of ribonucleotide reductase), whereby BRCA1-mediated RRM2 expression protects GBM cells from endogenous RS, DD and apoptosis. Notably, we show that treatment with a RRM2 inhibitor triapine reproduces the BRCA1-depletion GBM-repressive phenotypes and sensitizes GBM cells to PARP inhibition. We propose that GBM cells are addicted to the RS-protective role of the BRCA1-RRM2 axis, targeting of which may represent a novel paradigm for therapeutic intervention in GBM.
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PMID:BRCA1-regulated RRM2 expression protects glioblastoma cells from endogenous replication stress and promotes tumorigenicity. 3056 33