NCYM,a Cis-Antisense Gene of MYCN,Encodes a De Novo Evolved Protein That Inhibits GSK3β Resulting in the Stabilization of MYCN in Human Neuroblastomas

The rearrangement of pre-existing genes has long been thought of as the major mode of new gene generation. Recently, de novo gene birth from non-genic DNA was found to be an alternative mechanism to generate novel protein-coding genes. However, its functional role in human disease remains largely unknown. Here we show that NCYM, a cis-antisense gene of the MYCN oncogene, initially thought to be a large non-coding RNA, encodes a de novo evolved protein regulating the pathogenesis of human cancers, particularly neuroblastoma. The NCYM gene is evolutionally conserved only in the taxonomic group containing humans and chimpanzees. In primary human neuroblastomas, NCYM is 100% co-amplified and co-expressed with MYCN, and NCYM mRNA expression is associated with poor clinical outcome. MYCN directly transactivates both NCYM and MYCN mRNA, whereas NCYM stabilizes MYCN protein by inhibiting the activity of GSK3β, a kinase that promotes MYCN degradation. In contrast to MYCN transgenic mice, neuroblastomas in MYCN/NCYM double transgenic mice were frequently accompanied by distant metastases, behavior reminiscent of human neuroblastomas with MYCN amplification. The NCYM protein also interacts with GSK3β, thereby stabilizing the MYCN protein in the tumors of the MYCN/NCYM double transgenic mice. Thus, these results suggest that GSK3β inhibition by NCYM stabilizes the MYCN protein both in vitro and in vivo. Furthermore, the survival of MYCN transgenic mice bearing neuroblastoma was improved by treatment with NVP-BEZ235, a dual PI3K/mTOR inhibitor shown to destabilize MYCN via GSK3β activation. In contrast, tumors caused in MYCN/NCYM double transgenic mice showed chemo-resistance to the drug. Collectively, our results show that NCYM is the first de novo evolved protein known to act as an oncopromoting factor in human cancer, and suggest that de novo evolved proteins may functionally characterize human disease.     

Enhanced plasma ghrelin levels in rats with streptozotocin-induced diabetes

Human saliva, which contains nitrite, is normally mixed with gastric juice, which contains ascorbic acid (AA). When saliva was mixed with an acidic buffer in the presence of 0.1 mM AA, rapid nitric oxide formation and oxygen uptake were observed. The oxygen uptake was due to the oxidation of nitric oxide, which was formed by AA-dependent reduction of nitrite under acidic conditions, by molecular oxygen. A salivary component SCN⁻ enhanced the nitric oxide formation and oxygen uptake by the AA/nitrite system. The oxygen uptake by the AA/nitrite/SCN⁻ system was also observed in an acidic buffer solution. These results suggest that oxygen is normally taken up in the stomach when saliva and gastric juice are mixed.     

Evidence for detection of rat P2X4 receptor expressed on cells by generating monoclonal antibodies recognizing the native structure

Purinergic Signalling - P2X purinergic receptors are ATP-driven ionic channels expressed as trimers and showing various functions. A subtype, the P2X4 receptor present on microglial cells is highly...     

The law of payoff consistency: Games with continuous differences on resource values

We analyzed general continuous games in which two players compete for a resource with a different value. There is a pure ESS function in which an increase in the resource value increases the cost which players are willing to pay to obtain the resource. We also found that the expected payoff of the player does not change at all, even if the rules of the game were changed. If the rules of a contest become more costly and more vain, the cost equilibrium of the contest would become lower and perfectly cancel the effect of the change in the rules. The payoff is affected only by the distribution of resource value. This implies that however costly and however vain a contest in nature appears, it would not immediately relate with the individual’s loss and species benefit. We name this phenomenon “the law of payoff consistency”.     

Plant symbiotic microorganisms in acid sulfate soil: significance in the growth of pioneer plants

Acid sulfate soil is generated by chemical and microbial oxidization of sulfide-rich minerals/sediments. Although revegetation of the soil is difficult due to low-pH and poor nutrient availability, pioneer plants may adapt to such an extreme environment via associating with mycorrhizal fungi and/or N-fixing bacteria for acquisition of mineral nutrients. In this study, an abandoned quarry in which acid sulfate soil was found was chosen to investigate the influence of soil acidity on the levels of colonization by the microsymbionts, the identities of the microsymbionts that associated with pioneer plants and the dependency of pioneer plants on the microsymbionts. The levels of arbuscular mycorrhizal (AM) colonization in pioneer grass, forbs and legume shrubs grown in the field were assessed, and no significant decline in the levels with an increase in soil acidity was observed. Most of the legume shrubs formed root nodules. Several AM fungi and bradyrhizobia were cultured from the rhizosphere soils of pioneer plants grown in the quarry and identified based on the sequences of the small subunit ribosomal RNA genes. Pot experiments revealed that the microsymbionts isolated from the field significantly promoted the growths of pioneer grasses and legume shrubs in acid sulfate soil at pH 3.4. These results suggest that plant–microbial symbiotic associations play significant roles in the growth of pioneer plants in acid sulfate soil.     

Successful retrograde transport of fluorescent latex nanospheres in the cerebral cortex of the macaque monkey.

Retrograde axonal transport of latex nanospheres offers a means of delivering chemical agents to a targeted region of the central nervous system (CNS). In this study we performed microinjections of latex nanospheres into the cerebral cortex of cynomolgus monkeys and observed successful retrograde labeling of neurons in the contralateral region. Our data indicate the successful use of this delivery system, reported in studies using other animals, may also be achievable with primates as well.     

Hypoxic stress activates chaperone-mediated autophagy and modulates neuronal cell survival

Autophagy is a conserved mechanism responsible for the continuous clearance of unnecessary organelles or misfolded proteins in lysosomes. Three types of autophagy have been reported in the difference of substrate delivery to lysosome: macroautophagy, microautophagy, and chaperone-mediated autophagy (CMA). Among these types, CMA is a unique autophagy system that selectively degrades substrates detected by heat shock cognate protein 70 (HSC70). Recently, autophagic cell death has been reported to be involved in neuronal death following brain ischemia; however, the contribution of CMA to neuronal death/survival after ischemic stress has not been addressed. In the present study, we determined whether quantitative alterations in LAMP-2A, which is the key molecule in CMA, would modulate neuronal cell survival under hypoxic conditions. Incubation of Neuro2A cells in a hypoxic chamber (1% O(2), 5% CO(2)) increased the level of LAMP-2A and induced accumulation of LAMP-2A-positive lysosomes in the perinuclear area, which is a hallmark of CMA activation. The activation of CMA in response to hypoxia was also confirmed by the GAPDH-HaloTag CMA indicator system at the single cell level. Next, we asked whether CMA was involved in cell survival during hypoxia. Blocking LAMP-2A expression with siRNA increased the level of cleaved caspase-3 and the number of propidium iodide-positive cells after hypoxic stress regardless of whether macroautophagy could occur, whereas the administration of mycophenolic acid, a potent CMA activator, rescued hypoxia-mediated cell death. Finally, we asked whether CMA was activated in the neurons after middle cerebral artery occlusion in vivo. The expression of LAMP-2A was significantly increased in the ischemic hemisphere seven days after brain ischemia. These results indicate that CMA is activated during hypoxia and contributes to the survival of cells under these conditions.     

The luminal domain participates in the endosomal trafficking of the cation-independent mannose 6-phosphate receptor

Although the role of the cytoplasmic tail of the cation-independent mannose 6-phosphate receptor (CIMPR) has been well established in the receptor trafficking, that of the luminal domain is still controversial. We noticed that the peripheral distribution of GFP, fused to the transmembrane and cytoplasmic domains of CIMPR (G-CIMPR-tail), was distinct from that of endogenous CIMPR or of GFP fused to the full-length CIMPR (G-CIMPR-full). By live-cell imaging, trans-Golgi-network (TGN)-derived transport carriers containing G-CIMPR-full more frequently stopped and overlapped with transferrin-containing endosomes in the peripheral region than those containing G-CIMPR-tail. G-CIMPR-full was recycled back to the perinuclear TGN more slowly than that for G-CIMPR-tail, evidenced by fluorescence recovery after photobleaching analysis. Moreover, endogenous CIMPR and G-CIMPR-full, but not GFP-CIMPR-tail, drastically altered the characteristic distribution after treatment with chloroquine. A mutant receptor, G-CIMPR-full R/A, that cannot recognize the mannose 6-phosphate (M6P)-signal, behaved similarly to G-CIMPR-full, indicating that these differences are not attributable to the M6P-ligands binding situation. Interestingly, we also found that U18666A treatment was able to discriminate the M6P-ligand binding-dependent trafficking of CIMPR. Based on these findings, we propose that the CIMPR luminal domain is required for tight interaction with endocytic compartments, and retention by them, and that there are additional transport steps, in which the binding to M6P-ligands is involved.     

Testing metabolic ecology theory for allometric scaling of tree size, growth and mortality in tropical forests

The theory of metabolic ecology predicts specific relationships among tree stem diameter, biomass, height, growth and mortality. As demographic rates are important to estimates of carbon fluxes in forests, this theory might offer important insights into the global carbon budget, and deserves careful assessment. We assembled data from 10 old-growth tropical forests encompassing censuses of 367 ha and > 1.7 million trees to test the theory's predictions. We also developed a set of alternative predictions that retained some assumptions of metabolic ecology while also considering how availability of a key limiting resource, light, changes with tree size. Our results show that there are no universal scaling relationships of growth or mortality with size among trees in tropical forests. Observed patterns were consistent with our alternative model in the one site where we had the data necessary to evaluate it, and were inconsistent with the predictions of metabolic ecology in all forests.