Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

C2-ceramide, a cell-permeable analogue of ceramide, induced significant, dose- and time-dependent death in human retinoblastoma Y79 cells. Dying cells strongly displayed the morphology of apoptosis as characterized by microscopic evidence of cell shrinkage, membrane blebbing, nuclear and chromatin condensation and degeneration of the nucleus into membrane-bound apoptotic bodies. Upon induction of apoptosis Y79 cells evidence early phosphatidylserine externalization, as shown by annexin V-FITC. Apoptosis was also assessed by monitoring changes in cell granularity by staining with the combined fluorescent dyes acridine orange and ethidium bromide. C2-ceramide induced these morphological changes without a concomitant production of oligonucleosomal fragments responsible for the DNA ladder and without changes in p53 protein level. Apoptosis was accompanied by accumulation of a modified Bcl-2 protein with a slower-mobility form, and by proteolytic cleavage of PARP. The effect seemed to be specific for C2-ceramide, as C2-dihydroceramide, or other amphiphilic lipid analogues, or products of ceramide hydrolysis were ineffective. The effect also depended on mRNA and protein synthesis as it was markedly inhibited by actinomycin D and cycloheximide. Sphingomyelinase and interleukin-1beta, which are known to activate the sphingomyelin turnover leading to ceramide generation, also induced apoptosis mimicking the effects of ceramide. These findings propose ceramide as an activator of the suicidal program in Y79 cells.
Mol Cell Biochem 1998 Aug
PMID:Induction of programmed cell death in human retinoblastoma Y79 cells by C2-ceramide. 974 6

We report a new detection method for the purification of poly(ADP-ribose) polymerase (PARP). PARP purification generates many fractions in which PARP is usually detected by a time consuming activity assay. The development of a new method was also needed in order to decrease the utilization of radioactivity. This new method, based on an enzyme-linked immunosorbent assay (ELISA), is very rapid, sensitive, and avoids most radioactivity. Moreover, to illustrate this method, a new matrix was used, the Heparin Sepharose. This matrix was chosen for its affinity for the DNA binding proteins and because it allows the separation of whole PARP from its proteolytic fragments.
Mol Cell Biochem 1998 Aug
PMID:Rapid detection of poly(ADP-ribose) polymerase by enzyme-linked immunosorbent assay during its purification and improvement of its purification. 974 27

Trypanosoma brucei undergoes dramatic stage-specific changes in surface antigen expression, metabolic development, cellular morphogenesis and cell-cycle control. These events can be studied in detail during the transition between the bloodstream stumpy stage and the tsetse fly midgut procyclic form. This differentiation can be induced in vitro, is synchronous in the population and there are abundant markers for stage-regulated and differentiation events. We have used this differentiation system to investigate the role of de novo transcription during different phases of this well-characterised cellular transformation. Our experiments implicate early transcriptional involvement in shedding of the variable surface glycoprotein coat, cell restructuring and cell-cycle re-entry. The synchrony of differentiation has also been exploited to identify transcripts which define distinct regulated processes during this differentiation. The transcripts identified provide good coverage of the different molecular regulation events that accompany this life-cycle transformation. These included a surface antigen gene (encoding procyclin/PARP), a cell cycle regulated component (encoding histone H2B), a homologue of the Leishmania activated protein kinase C receptor (LACK) and a putative gene for sub unit VI of cytochrome c oxidase.
Mol Biochem Parasitol 1998 Sep 01
PMID:Identification of stage-regulated and differentiation-enriched transcripts during transformation of the African trypanosome from its bloodstream to procyclic form. 976 91

The caspases have been shown to be key components of programmed cell death (PCD) in various cell types, including neurons. Caspase-3 (CPP32) is the predominant caspase that appears to be involved in cell death in several systems. In embryonic motoneuron cultures, caspase-3 activity increases beginning at 20 h following deprivation of trophic support, as determined by the cleavage of its specific substrates. Inhibition of caspase-3 by peptide inhibitors prevents the PCD of motoneurons following trophic factor deprivation in vitro, as well as in vivo. We also investigated the cleavage of poly(ADP-ribose) polymerase (PARP) in motoneurons after trophic factor withdrawal. No PARP cleavage was detected in either viable or dying cells. These data suggest that some components of the cell death machinery such as the involvement of caspases may be conserved in different cell types undergoing PCD, whereas the activation and specific substrates of the caspases may differ from one cell type to another.
Mol Cell Neurosci 1998 Oct
PMID:Involvement of specific caspases in motoneuron cell death in vivo and in vitro following trophic factor deprivation. 979 Jul 36

Treatment of human neuroblastoma SH-SY5Y cells with 1 mM 1-methyl-4-phenylpyridinium (MPP+) for 3 days induced production of reactive oxygen species (ROS), followed by caspase-3 activation, cleavage of poly(ADP-ribose) polymerase (PARP), and apoptotic cell death with DNA fragmentation and characteristic morphological changes (condensed chromatin and fragmented nuclei). Simultaneous treatment with 1 mM talipexole slightly inhibited the MPP+-induced ROS production and apoptotic cell death. In contrast, pretreatment with 1 mM talipexole for 4 days markedly protected the cells against MPP+-induced apoptosis. However, this protective effect might not be mediated by dopamine receptors. The talipexole pretreatment induced an increase in antiapoptotic Bcl-2 protein level but had no effect on levels of proapoptotic Bax, Bak, and Bad. It also inhibited MPP+-induced ROS production, p53 expression, and cleavages of caspase-3 and PARP. Similarly, pramipexole pretreatment increased Bcl-2 and inhibited MPP+-induced apoptosis. Although pretreatment with bromocriptine also had a protective effect against MPP+-induced apoptosis, it had no effect on the protein levels of Bcl-2 family members. On the other hand, N6,2'-O-dibutyryl cAMP or calphostin C induced a decreased Bcl-2 level and enhanced MPP+-induced cell death. These results suggest that talipexole has dual actions: (1) it directly scavenges ROS, affording slight protection against MPP+-induced apoptosis, and (2) it induces Bcl-2 expression, thereby affording more potent protection, if it is administrated before MPP+. Pramipexole has similar effects, whereas bromocriptine seems to exhibit the former but not the latter effect.
Mol Pharmacol 1998 Dec
PMID:Protective effects of the antiparkinsonian drugs talipexole and pramipexole against 1-methyl-4-phenylpyridinium-induced apoptotic death in human neuroblastoma SH-SY5Y cells. 985 33

Striated muscle-specific expression of the cardiac troponin T (cTNT) gene is mediated through two MCAT elements that act via binding of transcription enhancer factor 1 (TEF-1) to the MCAT core motifs and binding of an auxiliary protein to nucleotides flanking the 5' side of the core motif. Using DNA-protein and protein-protein binding experiments, we identified a 140-kDa polypeptide that bound both the muscle-specific flanking sequences of the most distal MCAT1 element and TEF-1. Screening of an expression library with the MCAT1 element yielded a cDNA encoding a truncated form of poly(ADP-ribose) polymerase (PARP). Endogenous PARP from embryonic tissue nuclear extracts migrated as a 140-kDa protein. Recombinant full-length PARP preferentially bound the wild-type MCAT1 element and was shown to physically interact with TEF-1. In addition, endogenous TEF-1 could be coimmunoprecipitated with PARP from extracts of primary skeletal muscle cells. Recombinant PARP was able to ADP-ribosylate TEF-1 in vitro. Inhibition of the enzymatic activity of PARP repressed expression of an MCAT1-dependent reporter in transiently transfected primary muscle cells. Together, these data implicate PARP as the auxiliary protein that binds with TEF-1 to the MCAT1 element to provide muscle-specific gene transcription.
Mol Cell Biol 1999 Jan
PMID:Poly(ADP-ribose) polymerase binds with transcription enhancer factor 1 to MCAT1 elements to regulate muscle-specific transcription. 985 53

Streptozotocin (STZ) is believed to induce pancreatic beta cell death in mice by depleting the cell of NAD+NADH. The drug is known to cause a greater depletion of beta cell NAD+NADH in C57bl/6J mice than in Balb/c mice. To investigate the basis for this strain difference, we compared the effects of streptozotocin on poly(ADP-ribose)polymerase (PARP) activation - the major site of NAD consumption, and on mitochondrial activity - the major site of NAD production.%A significant strain difference was demonstrated in STZ-induced PARP activation (fmol NAD incorporated/min/microgram DNA+/-s.e.m.: Balb/c control 2.28+/-0.14, Balb STZ 3.11+/-0.25; C57bl/6J control 2.57+/-0.29, C57bl/6J STZ 4.17+/-0.24). In comparison, no strain difference could be demonstrated in hydrogen-peroxide-induced PARP activation. No strain differences could be detected in the activity of STZ-treated islet mitochondria as measured by determining ATP production (pmol/microgram protein/h+/-s. e.m.: Balb/c control 0.20+/-0.02, Balb/c STZ 0.15+/-0.02; C57bl/6J control 0.23+/- 0.03, C57bl/6J STZ 0.15+/-0.02) or by 3-[4, 5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) dye reduction (change in optical density/mg protein+/-s.e.m.: Balb/c control 10.19+/-0.62, Balb/c STZ 6.01+/-1.17; C57bl/6J control 6. 15+/-0.98, C57bl/6J STZ 5.81+/-0.96).% The strain difference in STZ-induced NAD depletion appears to be due to a difference in NAD consumption and not a difference in a mitochondrial process involved in replacing decreasing NAD concentrations. It is unlikely that a strain difference in the enzymic activity of PARP is responsible for strain differences in the effects of STZ, as no strain differences in hydrogen-peroxide-induced PARP activation could be detected. Thus the greater PARP activation, NAD depletion and beta cell death observed in C57bl/6J islets may be due to greater levels of DNA damage or differences in the DNA excision repair processes.
J Mol Endocrinol 1999 Feb
PMID:Poly(ADP-ribose)polymerase activation determines strain sensitivity to streptozotocin-induced beta cell death in inbred mice. 992 81

Mammalian poly(ADP-ribose) polymerase (PARP) is a nuclear chromatin-associated protein with a molecular mass of 114 kDa that catalyzes the transfer of ADP-ribose units from NAD+ to nuclear proteins that are located within chromatin. We report here the identification of a novel property of PARP as a modulator of nuclear receptor signalling. PARP bound directly to retinoid X receptors (RXR) and repressed ligand-dependent transcriptional activities mediated by heterodimers of RXR and thyroid hormone receptor (TR). The interacting surface is located in the DNA binding domain of RXRalpha. Gel shift assays demonstrated that PARP bound to TR-RXR heterodimers on the response element. Overexpression of wild-type PARP selectively blocked nuclear receptor function in transient transfection experiments, while enzyme-defective mutant PARP did not show significant inhibition, suggesting that the essential role of poly(ADP-ribosyl) enzymatic activity is in gene regulation by nuclear receptors. Furthermore, PARP fused to the Gal4 DNA binding domain suppressed the transcriptional activity of the promoter harboring the Gal4 binding site. Thus, PARP has transcriptional repressor activity when recruited to the promoter. These results indicates that poly(ADP-ribosyl)ation is a negative cofactor in gene transcription, regulating a member of the nuclear receptor superfamily.
Mol Cell Biol 1999 Apr
PMID:Inhibition of nuclear receptor signalling by poly(ADP-ribose) polymerase. 1008 30

First-generation inducible expression vectors for Trypanosoma brucei utilized a single tetracycline-responsive promoter to drive expression of an experimental gene, in tandem with a drug-resistance marker gene to select for integration (Wirtz E, Clayton CE. Science 1995; 268:1179-1183). Because drug resistance and experimental gene expression both depended upon the activity of the regulated promoter, this approach could not be used for inducible expression of toxic products. We have now developed a dual-promoter approach, for expressing highly toxic products and generating conditional gene knock-outs, using back-to-back constitutive T7 and tetracycline-responsive PARP promoters to drive expression of the selectable marker and test gene, respectively. Transformants are readily obtained with these vectors in the absence of tetracycline, in bloodstream or procyclic T. brucei cell lines co-expressing T7 RNA polymerase and Tet repressor, and consistently show tetracycline-responsive expression through a 10(3)-10(4)-fold range. Uninduced background expression of a luciferase reporter averages no more than one molecule per cell, enabling dominant-negative approaches relying upon inducible expression of toxic products. This tight regulation also permits the production of functional gene knock-outs through regulated expression of an experimental gene in a null-mutant background.
Mol Biochem Parasitol 1999 Mar 15
PMID:A tightly regulated inducible expression system for conditional gene knock-outs and dominant-negative genetics in Trypanosoma brucei. 1021 27

Aging is associated with altered immune function. We previously reported that splenocytes and thymocytes undergo apoptosis with aging in rats. In the present study, we examined the expression of genes associated with apoptosis in splenocytes and thymus in aging rats. We evaluated the expression of bax, interleukin 1-beta-converting enzyme (ICE)/ced-3 protease family, caspase-3 and tumor suppressor gene p53. Rats in age groups of 6, 24, 48, and 96 weeks were sacrificed; thymocytes and splenocytes were isolated followed by lysis in a modified RIPA buffer containing protease inhibitors. Western blot analysis of proteins was performed by probing immunoblots with antibodies against p53, bax and PARP (poly ADP-ribose polymerase). Increased aging was associated with enhanced expression of bax, p53 and cleavage of PARP by Caspase-3. The expression of p53 and cleavage of PARP indicates the presence of damaged DNA; nevertheless, the cleavage of PARP or activation of caspase-3 may be playing an important role in the initiation of early events in apoptosis. These results suggest that aging of splenocytes and thymocytes is associated with the expression of cell death genes. The present study provides an insight into age-associated altered immune function.
Mol Cell Biol Res Commun 1999 Apr
PMID:Aging splenocyte and thymocyte apoptosis is associated with enhanced expression of p53, bax, and caspase-3. 1032 82


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>