Radiation Signal Transduction Research Articles

Study on Plant Radiation Signal Transduction for Human Self-Healing

We selected 450 patients with chronic and difficult diseases as receptors, and selected edible and medicinal plant combinations as biological signal donors, and randomly participated in a new experiment. After adjusting the patient’s biological field, the compensating bio information energy (CBE) high-tech is applied to transmit the signal of plant radiation to the patient’s body. The physical therapy of this health care mode has the characteristics of no contact, no drugs, no intervention, no toxic side effects, no pain, and no electromagnetic radiation and so on. Before and after the experiment, the main function test, cell function, cell biochemistry and body temperature of each patient were used for the same body control and data statistical analysis, and then the comprehensive integration method was used to evaluate the effect. We found that after 1 - 4 courses of treatment (7 - 28 dx 2h), the potential disease risk of patients was significantly reduced, the relevant medical indicators improved rapidly, and the cell function and symptoms improved simultaneously. The effective rate was up to 90%, the significant efficiency was up to 57%. This experiment shows that this new physical therapy can treat both symptoms and root causes, make chronic and difficult diseases self-healing and rehabilitation, and has no ethical problems. It also shows that information on plant health can play an important role in reversing cell aging and restoring cell function. Therefore, it opens up a new field of natural therapy, which can be called cell information therapy.

Chalcone isomerase-like genes in Tradescantia BNL4430: identification, molecular characterization, and differential expression profiles under Ɣ-radiation stress

Chalcone isomerase (CHI) is an important catalytic enzyme that converts naringenin (chalcone) to (2S)-naringenin in phenylpropanoid pathway. Here, we performed the first comprehensive molecular genetic study on Chalcone isomerase genes in Tradescantia clone BNL 4430 (designated as TrCHI). We identified seven TrCHIs genes (five with full length and two with partial length) through in silico analysis using available transcriptomic resources. Phylogenetic analysis suggest that TrCHIs are closely related to rice CHI. TrCHIs fall into three different CHI subfamilies: (1) type I (TrCHI2 including TrCHI2a, 2b, 2c, and 2d), (2) type III (TrCHI3 including TrCHI3B and 3C), and (3) type IV (TrCHI4). These partial or full length TrCHI genes were 456–819 bp in length with molecular mass ranging from 23 kDa to 47 kDa. Type I (TrCHI2) subfamily has the conserved active substrate binding sites similar to previously reported CHIs. The predicted tertiary structures of TrCHI2b showed structural configurations consistent with AtCHIs, suggesting that type I (TrCHI2) subfamily members of CHI might have active roles in flavonoid production. Real-time quantitative polymerase chain reaction (qRT-PCR) revealed that TrCHIs were expressed in a tissue-specific manner. TrCHIs in flowers under Ɣ–radiation treatment were up-regulated, indicating their potential action against radiation stress. Their regulation might be correlated with the presence of a few cis elements in their promoters. Our results provided a basis for functional study of flower pigmentation and breeding for novel flower color. They will also help us to elucidate radiation signal transduction pathways in Tradescantia.

Down-regulation of catalase activity contributes to senescence induction in wheat leaves exposed to shading stress

In shaded wheat (Triticum aestivum L.) leaves, the suppression of blue radiation (BR) triggers senescence. This phenomenon is correlated to an increase in oxidative stress symptoms and a decrease of catalase (CAT) activity, among other traits. Previous data suggest that the radiation signal transduction pathway may involve changes in Ca2+ and H2O2 homeostasis. For better a understanding of the interaction among the spectral composition of radiation, Ca2+ availability, and the antioxidant metabolism in the regulation of shade-induced senescence, detached wheat leaves were placed in a growth chamber and exposed to either blue (B, high BR transmittance) and/or green (G, very low BR transmittance) Lee® filters in the absence or presence of 0.8 mM verapamil (a Ca2+ channels blocker), 4.0 mM EGTA (a Ca2+chelator), or 8.0 mM 3-amino-1,2,4-triazole (a CAT inhibitor). At defined time points, the leaf samples were analyzed for changes in chlorophyll content, specific activities of CAT, ascorbate peroxidase (APX), and guaiacol peroxidase (POX), CAT isozymes, and gene expression of CAT1, CAT2, and two senescence markers (TaSAG1 and TaSAG3). BR transmittance decreased the chlorophyll degradation rate and SAG genes expression either in leaves continuously exposed under the B filter, as well as in leaves previously exposed under the G filter. The effect of BR was associated with the maintenance of a high CAT (but not APX and POX) activity, and it was suppressed either in the presence of 3-AT or when Ca2+ availability was decreased. BR altered the CAT activity both at the transcriptional and at the posttranscriptional level. Nevertheless, different responses of CAT isozymes and CAT genes expression profiles to specific treatment combinations indicate that they differed in their regulatory pathways.

Signal Transduction and Cellular Responses to Ionizing Radiation.

The current understanding of cellular responses to ionizing radiation fuses traditional radiobiological concepts with recent insight into underlying molecular mechanisms. Cell cycle arrest, induction of specific cascades of genes, and activation of DNA repair mechanisms have been reported after radiation exposure. Of particular importance is the mitogen-activated protein (MAP) kinase signaling pathway, in which the ras and raf oncogenes participate. Both of these genes have been implicated in the cellular resistance to killing by ionizing radiation. Furthermore, regulated NF-gammaB transcriptional activation may be important for the pleiotrophic responses of cells to ionizing radiation. Disruption of this signaling cascade may contribute to the radiation sensitivity syndrome seen in ataxia telangiectasia. In this review, these pathways are consolidated into ionizing radiation signal transduction pathways that lead from the cell membrane/cytosol to the nuclear DNA.

Novel Localization of the DNA-PK Complex in Lipid Rafts: A PUTATIVE ROLE IN THE SIGNAL TRANSDUCTION PATHWAY OF THE IONIZING RADIATION RESPONSE

Increased sensitivity to ionizing radiation (IR) has been shown to be due to defects in DNA double-strand break repair machinery. The major pathway in mammalian cells dedicated to the repair of DNA double-strand breaks is by the nonhomologous end-joining machinery. Six components function in this pathway, of which three (Ku70, Ku86, and DNA-PKcs) constitute a protein complex known as DNA-dependent protein kinase (DNA-PK). However, it is now recognized that the cellular radiation response is complex, and radiosensitivity may be also regulated at different levels in the radiation signal transduction pathway. In addition to DNA damage, exposure to IR triggers intracellular signaling cascades that overlap with pathways initiated by ligand engagement to a receptor. In this study, we provide evidence for the novel localization of the DNA-PK complex in lipid rafts. We also show this property is not a generalized characteristic of all DNA repair proteins. Furthermore, we have detected Ku86 in yeast lipid rafts. Our results suggest that the components of this complex might be recruited separately to the plasma membrane by tethering with raft-resident proteins. In addition, we found an irradiation-induced differential protein phosphorylation pattern dependent upon DNA-PKcs in lipid rafts. Thus, we speculate that another role for the DNA-PKcs subunit and perhaps for the holoenzyme is in the signal transduction of IR response.

Erratum: The relative role of ErbB1–4 receptor tyrosine kinases in radiation signal transduction responses of human carcinoma cells

Erratum: The relative role of ErbB1–4 receptor tyrosine kinases in radiation signal transduction responses of human carcinoma cells

Defective radiation signal transduction in ataxia-telangiectasia cells

Purpose : The product of the gene ATM mutated in the human genetic disorder ataxia-telangiectasia (A-T) is predominantly present in the nucleus compatible with a role in DNA-damage recognition and cell-cycle control. However, ATM is also present outside the nucleus in cytoplasmic and membrane associated vesicles, which may explain the more general signalling defect in A-T. This led us to investigate signalling events initiated by ionizing radiation, remote from the nucleus. Materials and Methods : A-T and control lymphoblastoid cells were employed to study radiation-induced signalling at the level of protein activation using immunoprecipitation and immunoblotting. Flow cytometry was used to determine mobilization of intracellular Ca 2. Results : Lymphoblastoid cells from A-T patients were found to be defective in the radiation-induced activation of protein tyrosine kinase p53/p56lyn. In control cells Ca 2 was mobilized in response to gamma-radiation largely from internal stores, and increased significantly over a 20 min period. This mobilization of Ca2 was either absent or increased very slowly in A-T cells post-irradiation. The same pattern of release was observed after treatment with the radiometric agent, streptonigrin. In addition the phospatidylinositol 3-kinase (PI3-kinase) inhibitor wortmannin suppressed the release of Ca 2. Conclusion : These data demonstrate that ionizing radiation activates lyn kinase and leads to the release of Ca 2, and-for the first time-that these steps are ATM-dependent.

Cloning and Expression of the Ataxia–Telangiectasia Gene in Baculovirus

The gene mutated in the human genetic disorder ataxia–telangiectasia, ATM, is implicated in the response to radiation-induced DNA damage and to a more widespread signalling defect. The ATM protein is predominantly a nuclear protein where it interacts with p53 and c-Abl as part of a radiation signal transduction pathway(s). We describe here the cloning of full-length ATM cDNA in a baculovirus vector to produce recombinant protein. Expression of ATM, as a soluble protein, was observed by 36 h post-infection using immunoblotting with anti-ATM antibody. The presence of a hexahistidine tag on ATM was used as the basis for purification of the protein by affinity chromatography. The protein yield was only 20 ng/100 ml of infected cells, presumably because of the size of the protein and adverse effects on cell growth when overexpressed. ATM was found to have autophosphorylation activity in immunoprecipitates with antibodies directed against the hexahistidine tag sequence. These results demonstrate that ATM can be expressed inefficiently in baculovirus infected insect cells and the data suggest that it phosphorylates itself.

Late G1 accumulation after 2 Gy of gamma-irradiation is related to endogenous Raf-1 protein expression and intrinsic radiosensitivity in human cells.

We have previously reported a correlation between high endogenous expression of the protein product of the RAF-1 proto-oncogene, intrinsic cellular radiosensitivity and rapid exit from a G2/M delay induced by 2 Gy of gamma-irradiation. Raf1 is a positive serine/threonine kinase signal transduction factor that relays signals from the cell membrane to the MAP kinase system further downstream and is believed to be involved in an ionizing radiation signal transduction pathway modulating the G1/S checkpoint. We therefore extended our flow cytometric studies to investigate relationships between radiosensitivity, endogenous expression of the Raf1 protein and perturbation of cell cycle checkpoints, leading to alterations in the G1, S and G2/M populations after 2 Gy of gamma-irradiation. Differences in intrinsic radiosensitivity after modulation of the G1/S checkpoint have generally been understood to involve p53 function up to the present time. A role for dominant oncogenes in control of G1/S transit in radiation-treated cells has not been identified previously. Here, we show in 12 human in vitro cancer cell lines that late G1 accumulation after 2 Gy of radiation is related to both Raf1 expression (r = 0.91, P = 0.0001) and the radiosensitivity parameter SF2 (r = -0.71, P = 0.009).

Isolation of full-length ATM cDNA and correction of the ataxia-telangiectasia cellular phenotype.

A gene mutated in the human genetic disorder ataxia-telangiectasia (A-T), ATM, was recently identified by positional cloning. ATM is a member of the phosphatidylinositol-3-kinase superfamily, some of which are protein kinases and appear to have important roles in cell cycle control and radiation signal transduction. We describe herein, to our knowledge, for the first time, the cloning of a full-length cDNA for ATM and correction of multiple aspects of the radio-sensitive phenotype of A-T cells by transfection with this cDNA. Overexpression of ATM cDNA in A-T cells enhanced the survival of these cells in response to radiation exposure, decreased radiation-induced chromosome aberrations, reduced radio-resistant DNA synthesis, and partially corrected defective cell cycle checkpoints and induction of stress-activated protein kinase. This correction of the defects in A-T cells provides further evidence of the multiplicity of effector functions of the ATM protein and suggests possible approaches to gene therapy.

Signal transduction and cellular responses to ionizing radiation

The current understanding of cellular responses to ionizing radiation fuses traditional radiobiological concepts with recent insight into underlying molecular mechanims. Cell cycle arrest, induction of specific cascades of genes, and activation of DNA repair mechanisms have been reported after radiation exposure. Of particular importance is the mitogen-activated protein (MAP) kinase signaling pathway, in which the ras and raf oncogenes participate. Both of these genes have been implicated in the cellular resistance to killing by ionizing radiation. Furthermore, regulated NF- k B transcriptional activation may be important for the pleiotrophic responses of cells to ionizing radiation. Disruption of this signaling cascade may contribute to the radiation sensitivity syndrome seen in ataxia telangiectasia. In this review, these pathways are consolidated into ionizing radiation signal transduction pathways that lead from the cell membrane/cytosol to the nuclear DNA.

Induction of inositol 1,4,5 trisphosphate receptor genes by ionizing radiation.

We used differential display, a method designed to amplify partial cDNA sequences from subsets of mRNAs, to identify mRNAs induced by ionizing radiation in human Epstein Barr Virus (EBV)-transformed lymphoblastoid cells. Increased expression of a cDNA corresponding to the inositol 1,4,5 trisphosphate receptor (InsP3R) type 1 was observed after exposure of cells to 3Gy gamma-rays. This was confirmed by Northern blot analysis. The increase in mRNA for InsP3R type 1 was accompanied by a corresponding increase in the level of InsP3R type 1 protein as determined by Western blotting. Exposure of cells from patients with the human genetic disorder ataxia-telangiectasia (A-T), characterized by hypersensitivity to ionizing radiation, failed to change the levels of InsP3R type 1 mRNA and, as expected, there was no increase in InsP3R type 1 protein in A-T cells in response to radiation exposure. Protein levels for two other InsP3Rs, types 2 and 3, were observed to increase in control and A-T cells after exposure to ionizing radiation. The induction of the InsP3R type 1, which is primarily located in the endoplasmic reticulum, may play an important role in radiation signal transduction.

Defect in Radiation Signal Transduction in Ataxia-telangiectasia

Exposure of mammalian cells to ionizing radiation causes a delay in progression through the cycle at several checkpoints. Cells from patients with ataxia-telangiectasia (A-T) ignore these checkpoint controls postirradiation. The tumour suppressor gene product p53 plays a key role at the G1/S checkpoint preventing the progression of cells into S phase. The induction of p53 by radiation is reduced and/or delayed in A-T cells, which appears to account for the failure of delay at the G1/S checkpoint. We have investigated further this defect in radiation signal transduction in A-T. While the p53 response was defective after radiation, agents that interfered with cell cycle progression such as mimosine, aphidicolin and deprivation of serum led to a normal p53 response in A-T cells. None of these agents caused breaks in DNA, as determined by pulse-field gel electrophoresis, in order to elicit the response. Since this pathway is mediated by protein kinases, we investigated the activity of several of these enzymes in control and A-T cells. Ca+2-dependent and -independent protein kinase C activities were increased by radiation to the same extent in the two cell types, a variety of serine/threonine protein kinase activities were approximately the same and anti-tyrosine antibodies failed to reveal any differences in protein phosphorylation between A-T and control cells. It is not evident what is the nature of the defect in signal transduction in A-T cells. However, it is clear that the p53 response is normal in these cells after exposure to some agents and it is mediated through protein kinase C or another serine/threonine kinase.

Defect in radiation signal transduction in ataxia-telangiectasia

Defect in radiation signal transduction in ataxia-telangiectasia