Redirected nuclear glutamate dehydrogenase supplies Tet3 with alpha-ketoglutarate in neurons

Tet3 is the main alpha -ketoglutarate (alpha KG)-dependent dioxygenase in neurons that converts 5-methyl-dC into 5-hydroxymethyl-dC and further on to 5-formyl- and 5-carboxy-dC. Neurons possess high levels of 5-hydroxymethyl-dC that further increase during neural activity to establish transcriptional plasticity required for learning and memory functions. How alpha KG, which is mainly generated in mitochondria as an intermediate of the tricarboxylic acid cycle, is made available in the nucleus has remained an unresolved question in the connection between metabolism and epigenetics. We show that in neurons the mitochondrial enzyme glutamate dehydrogenase, which converts glutamate into alpha KG in an NAD(+)-dependent manner, is redirected to the nucleus by the alpha KG-consumer protein Tet3, suggesting on-site production of alpha KG. Further, glutamate dehydrogenase has a stimulatory effect on Tet3 demethylation activity in neurons, and neuronal activation increases the levels of alpha KG. Overall, the glutamate dehydrogenase-Tet3 interaction might have a role in epigenetic changes during neural plasticity. alpha -ketoglutarate (alpha KG) is an intermediate in the tricarboxylic acid cycle that is required in the nucleus for genomic DNA demethylation by Tet3. Here, the authors show that the enzyme glutamate dehydrogenase, which converts glutamate to alpha KG, is redirected from the mitochondria to the nucleus.Proteomic

Photoproduction of D∗±D^{*\pm} mesons associated with a leading neutron

The photoproduction of $D^{*\pm} (2010)$ mesons associated with a leading neutron has been observed with the ZEUS detector in $ep$ collisions at HERA using an integrated luminosity of 80 pb$^{-1}$. The neutron carries a large fraction, {$x_L>0.2$}, of the incoming proton beam energy and is detected at very small production angles, {$\theta_n<0.8$ mrad}, an indication of peripheral scattering. The $D^*$ meson is centrally produced with pseudorapidity {$|\eta| 1.9$ GeV}, which is large compared to the average transverse momentum of the neutron of 0.22 GeV. The ratio of neutron-tagged to inclusive $D^*$ production is $8.85\pm 0.93({\rm stat.})^{+0.48}_{-0.61}({\rm syst.})\%$ in the photon-proton center-of-mass energy range {$130 <W<280$ GeV}. The data suggest that the presence of a hard scale enhances the fraction of events with a leading neutron in the final state.Comment: 28 pages, 4 figures, 2 table

Three- and Four-Jet Final States in Photoproduction at HERA

Three- and four-jet final states have been measured in photoproduction at HERA using the ZEUS detector with an integrated luminosity of 121   pb -1. The results are presented for jets with transverse energy E Tjet &gt; 6   GeV and pseudorapidity | η jet | &lt; 2.4, in the kinematic region given by the virtuality of the photon Q 2 &lt; 1   GeV 2 and the inelasticity 0.2 ≤ y ≤ 0.85 and in two mass regions defined as 25 ≤ M n j &lt; 50   GeV and M n j ≥ 50   GeV, where M n j is the invariant mass of the n-jet system. The four-jet photoproduction cross section has been measured for the first time and represents the highest-order process studied at HERA. Both the three- and four-jet cross sections have been compared with leading-logarithmic parton-shower Monte Carlo models, with and without multi-parton interactions. The three-jet cross sections have been compared to an O (α α s2) perturbative QCD calculation. © 2007 Elsevier B.V. All rights reserved

Search for Stop Production in RR-Parity-Violating Supersymmetry at HERA.

A search for stop production in R-parity-violating supersymmetry has been performed in $e^{+}p$ interactions with the ZEUS detector at HERA, using an integrated luminosity of 65 pb$^{-1}$. At HERA, the R-parity-violating coupling $\lambda'$ allows resonant squark production, $e^+d\to\tilde{q}$. Since the lowest-mass squark state in most supersymmetry models is the light stop, $\tilde{t}$, this search concentrated on production of $\tilde{t}$, followed either by a direct R-parity-violating decay, or by the gauge decay to $b\tilde{\chi}^+_{1}$. No evidence for stop production was found and limits were set on $\lambda'_{131}$ as a function of the stop mass in the framework of the Minimal Supersymmetric Standard Model. The results have also been interpreted in terms of constraints on the parameters of the minimal Supergravity model.Comment: 24 pages, 11 figures, 1 table, Accepted by European Physical Journal