Memory and synaptic plasticity are impaired by dysregulated hippocampal O-GlcNAcylation

O-GlcNAcylated proteins are abundant in the brain and are associated with neuronal functions and neurodegenerative diseases. Although several studies have reported the effects of aberrant regulation of O-GlcNAcylation on brain function, the roles of O-GlcNAcylation in synaptic function remain unclear. To understand the effect of aberrant O-GlcNAcylation on the brain, we used Oga+/- mice which have an increased level of O-GlcNAcylation, and found that Oga+/- mice exhibited impaired spatial learning and memory. Consistent with this result, Oga+/- mice showed a defect in hippocampal synaptic plasticity. Oga heterozygosity causes impairment of both long-term potentiation and long-term depression due to dysregulation of AMPA receptor phosphorylation. These results demonstrate a role for hyper-O-GlcNAcylation in learning and memory.ope

Genomic organisation of the Mal d 1 gene cluster on linkage group 16 in apple

European populations exhibit progressive sensitisation to food allergens, and apples are one of the foods for which sensitisation is observed most frequently. Apple cultivars vary greatly in their allergenic characteristics, and a better understanding of the genetic basis of low allergenicity may therefore allow allergic individuals to increase their fruit intake. Mal d 1 is considered to be a major apple allergen, and this protein is encoded by the most complex allergen gene family. Not all Mal d 1 members are likely to be involved in allergenicity. Therefore, additional knowledge about the existence and characteristics of the different Mal d 1 genes is required. In the present study, we investigated the genomic organisation of the Mal d 1 gene cluster in linkage group 16 of apple through the sequencing of two bacterial artificial chromosome clones. The results provided new information on the composition of this family with respect to the number and orientation of functional and pseudogenes and their physical distances. The results were compared with the apple and peach genome sequences that have recently been made available. A broad analysis of the whole apple genome revealed the presence of new genes in this family, and a complete list of the observed Mal d 1 genes is supplied. Thus, this study provides an important contribution towards a better understanding of the genetics of the Mal d 1 family and establishes the basis for further research on allelic diversity among cultivars in relation to variation in allergenicity

Ribosome profiling reveals the what, when, where and how of protein synthesis

Ribosome profiling, which involves the deep sequencing of ribosome-protected mRNA fragments, is a powerful tool for globally monitoring translation in vivo. The method has facilitated discovery of the regulation of gene expression underlying diverse and complex biological processes, of important aspects of the mechanism of protein synthesis, and even of new proteins, by providing a systematic approach for experimental annotation of coding regions. Here, we introduce the methodology of ribosome profiling and discuss examples in which this approach has been a key factor in guiding biological discovery, including its prominent role in identifying thousands of novel translated short open reading frames and alternative translation products

CRYSTALLIZATION AND PRELIMINARY X-RAY ANALYSIS OF THE BETA-ISOFORM OF GLUTAMATE DECARBOXYLASE FROM ESCHERICHIA COLI.

Glutamate decarboxylase (GAD) is a vitamin B6 enzyme which catalyzes the α-decarboxylation of l-glutamate to γ-aminobutyric acid (GABA). Escherichia coli cells coexpress two highly homologous enzyme isoforms, GADα and GADβ. Well diffracting crystals of GADβ were obtained by taking advantage of the possibility of expressing each isoform separately. They belong to space group P31 or P32 with the unit-cell dimensions a = b = 115.6 and c = 206.6 Å and contain one GAD hexamer in the asymmetric unit. High-resolution synchrotron data were collected at 100 K for the native protein and a potential heavy-atom derivative

Functional crosstalk of PGC-1 coactivators and inflammation in skeletal muscle pathophysiology

Skeletal muscle is an organ involved in whole body movement and energy metabolism with the ability to dynamically adapt to different states of (dis-)use. At a molecular level, the peroxisome proliferator-activated receptor γ coactivators 1 (PGC-1s) are important mediators of oxidative metabolism in skeletal muscle and in other organs. Musculoskeletal disorders as well as obesity and its sequelae are associated with PGC-1 dysregulation in muscle with a concomitant local or systemic inflammatory reaction. In this review, we outline the function of PGC-1 coactivators in physiological and pathological conditions as well as the complex interplay of metabolic dysregulation and inflammation in obesity with special focus on skeletal muscle. We further put forward the hypothesis that, in this tissue, oxidative metabolism and inflammatory processes mutually antagonize each other. The nuclear factor κB (NF-κB) pathway thereby plays a key role in linking metabolic and inflammatory programs in muscle cells. We conclude this review with a perspective about the consequences of such a negative crosstalk on the immune system and the possibilities this opens for clinical applications

Mapping of bionic array electric field focusing in plasmid DNA-based gene electrotransfer

Molecular medicine through gene therapy is challenged to achieve targeted action. This is now possible utilizing bionic electrode arrays for focal delivery of naked (plasmid) DNA via gene electrotransfer. Here, we establish the properties of array-based electroporation affecting targeted gene delivery. An array with eight 300 μm platinum ring electrodes configured as a cochlear implant bionic interface was used to transduce HEK293 cell monolayers with a plasmid-DNA green fluorescent protein (GFP) reporter gene construct. Electroporation parameters were pulse intensity, number, duration, separation and electrode configuration. The latter determined the shape of the electric fields, which were mapped using a voltage probe. Electrode array-based electroporation was found to require ~100 × lower applied voltages for cell transduction than conventional electroporation. This was found to be due to compression of the field lines orthogonal to the array. A circular area of GFP-positive cells was created when the electrodes were ganged together as four adjacent anodes and four cathodes, whereas alternating electrode polarity created a linear area of GFP-positive cells. The refinement of gene delivery parameters was validated in vivo in the guinea pig cochlea. These findings have significant clinical ramifications, where spatiotemporal control of gene expression can be predicted by manipulation of the electric field via current steering at a cellular level

Sucrose mobilisation in sugarcane stalk induced by heterotrophic axillary bud growth

A theoretical high-yield sugarcane biofactory can be idealised as containing culm tissue that functions as a secondary source tissue rather than a sink. To investigate this potential process, heterotrophic axillary bud outgrowth from sugarcane (Saccharum spp. hybrids) setts was used as a model system to demonstrate that sucrose is a mobilisable carbon source. The outgrowth and subsequent biomass accumulation of axillary buds from two-eye setts of mature sugarcane stalks grown in the dark was used to measure carbon mobilisation from sett internode pith tissue. After 42 days growth 99.0 +/- 0.72% of sett internode pith sucrose was depleted and 2.66 +/- 0.16 g of new tissue accumulated. Comparison with a control treatment in which axillary buds were excised at day zero demonstrated that carbon mobilisation was driven by the accumulation of new biomass. Profiling of soluble carbohydrates (viz. sucrose, glucose and fructose), starch, total soluble protein, total amino nitrogen, free amino acids and total insoluble material showed that the sucrose stored in the sett internode pith was the only available carbon source of sufficient size at day zero for the observed biomass accumulation. Other metabolites mobilised were glucose, fructose and some amino acids, notably isoleucine and leucine that were depleted in shoot treatment setts at day 42