209 research outputs found

    Paradoxical Role of an Egr Transcription Factor Family Member, Egr2/Krox20, in Learning and Memory

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    It is well established that Egr1/zif268, a member of the Egr family of transcription factors, is critical for the consolidation of several forms of memories. Recently, the Egr3 family member has also been implicated in learning and memory. Because Egr family members encode closely related zinc-finger transcription factors sharing a highly homologous DNA binding domain that recognises the same DNA sequence, they may have related functions in brain. Another Egr family member expressed in brain, Egr2/Krox20 is known to be crucial for normal hindbrain development and has been implicated in several inherited peripheral neuropathies; however, due to Egr2-null mice perinatal lethality, its potential role in cognitive functions in the adult has not been yet explored. Here, we generated Egr2 conditional mutant mice allowing postnatal, forebrain-specific Cre-mediated Egr2 excision and tested homozygous, heterozygous and control littermates on a battery of behavioural tasks to evaluate motor capacity, exploratory behaviour, emotional reactivity and learning and memory performance in spatial and non-spatial tasks. Egr2-deficient mice had no sign of locomotor, exploratory or anxiety disturbances. Surprisingly, they also had no impairment in spatial learning and memory, taste aversion memory or fear memory using a trace conditioning paradigm. On the contrary, Egr2-deficient mice had improved performance in motor learning on a rotarod, and in object recognition memory. These results clearly do not extend the phenotypic consequences resulting from either Egr1 or Egr3 loss-of-function to Egr2. In contrast, they indicate that Egr family members may have different, and in certain circumstances antagonistic functions in the adult brain

    Distinct Functions of Egr Gene Family Members in Cognitive Processes

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    The different gene members of the Egr family of transcriptional regulators have often been considered to have related functions in brain, based on their co-expression in many cell-types and structures, the relatively high homology of the translated proteins and their ability to bind to the same consensus DNA binding sequence. Recent research, however, suggest this might not be the case. In this review, we focus on the current understanding of the functional roles of the different Egr family members in learning and memory. We briefly outline evidence from mutant mice that Egr1 is required specifically for the consolidation of long-term memory, while Egr3 is primarily essential for short-term memory. We also review our own recent findings from newly generated forebrain-specific conditional Egr2 mutant mice, which revealed that Egr2, as opposed to Egr1 and Egr3, is dispensable for several forms of learning and memory and on the contrary can act as an inhibitory constraint for certain cognitive functions. The studies reviewed here highlight the fact that Egr family members may have different, and in certain circumstances antagonistic functions in the adult brain

    802.11 network intrusion detection using genetic programming

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    Genetic Programming (GP) based Intrusion Detection Sys-tems (IDS) use connection state network data during their training phase. These connection states are recorded as a set of features that the GP uses to train and test solutions which allow for the efficient and accurate detection of given attack patterns. However, when applied to a 802.11 network that is faced with attacks specific to the 802.11 protocol, the GP’s detection rate reduces dramatically. In this work we discuss what causes this effect, and what can be done to improve the GP’s performance on 802.11 networks

    G-protein Signaling Modulator-3 Regulates Heterotrimeric G-protein Dynamics through Dual Association with Gβ and Gα i Protein Subunits

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    Regulation of the assembly and function of G-protein heterotrimers (Gα·GDP/Gβγ) is a complex process involving the participation of many accessory proteins. One of these regulators, GPSM3, is a member of a family of proteins containing one or more copies of a small regulatory motif known as the GoLoco (or GPR) motif. Although GPSM3 is known to bind Gαi·GDP subunits via its GoLoco motifs, here we report that GPSM3 also interacts with the Gβ subunits Gβ1 to Gβ4, independent of Gγ or Gα·GDP subunit interactions. Bimolecular fluorescence complementation studies suggest that the Gβ-GPSM3 complex is formed at, and transits through, the Golgi apparatus and also exists as a soluble complex in the cytoplasm. GPSM3 and Gβ co-localize endogenously in THP-1 cells at the plasma membrane and in a juxtanuclear compartment. We provide evidence that GPSM3 increases Gβ stability until formation of the Gβγ dimer, including association of the Gβ-GPSM3 complex with phosducin-like protein PhLP and T-complex protein 1 subunit eta (CCT7), two known chaperones of neosynthesized Gβ subunits. The Gβ interaction site within GPSM3 was mapped to a leucine-rich region proximal to the N-terminal side of its first GoLoco motif. Both Gβ and Gαi·GDP binding events are required for GPSM3 activity in inhibiting phospholipase-Cβ activation. GPSM3 is also shown in THP-1 cells to be important for Akt activation, a known Gβγ-dependent pathway. Discovery of a Gβ/GPSM3 interaction, independent of Gα·GDP and Gγ involvement, adds to the combinatorial complexity of the role of GPSM3 in heterotrimeric G-protein regulation

    Regulation of the Subcellular Localization of the G-protein Subunit Regulator GPSM3 through Direct Association with 14-3-3 Protein

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    G-protein signaling modulator-3 (GPSM3), also known as G18 or AGS4, is a member of the Gαi/o-Loco (GoLoco) motif containing proteins. GPSM3 acts through its two GoLoco motifs to exert GDP dissociation inhibitor activity over Gαi subunits; recently revealed is the existence of an additional regulatory site within GPSM3 directed toward monomeric Gβ subunits during their biosynthesis. Here, using in silico and proteomic approaches, we have found that GPSM3 also interacts directly with numerous members of the 14-3-3 protein family. This interaction is dependent on GPSM3 phosphorylation, creating a mode II consensus 14-3-3 binding site. 14-3-3 binding to the N-terminal disordered region of GPSM3 confers stabilization from protein degradation. The complex of GPSM3 and 14-3-3 is exclusively cytoplasmic, and both moieties mutually control their exclusion from the nucleus. Phosphorylation of GPSM3 by a proline-directed serine/threonine kinase and the resultant association of 14-3-3 is the first description of post-translational regulation of GPSM3 subcellular localization, a process that likely regulates important spatio-temporal aspects of G-protein-coupled receptor signaling modulation by GPSM3

    Characterization of the caleosin gene family in the Triticeae

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    Background The caleosin genes encode proteins with a single conserved EF hand calcium-binding domain and comprise small gene families found in a wide range of plant species. Some members of the gene family have been shown to be upregulated by environmental stresses including low water availability and high salinity. Caleosin 3 from wheat has been shown to interact with the α-subunit of the heterotrimeric G proteins, and to act as a GTPase activating protein (GAP). This study characterizes the size and diversity of the gene family in wheat and related species and characterizes the differential tissue-specific expression of members of the gene family. Results A total of 34 gene family members that belong to eleven paralogous groups of caleosins were identified in the hexaploid bread wheat, T. aestivum. Each group was represented by three homeologous copies of the gene located on corresponding homeologous chromosomes, except the caleosin 10, which has four gene copies. Ten gene family members were identified in diploid barley, Hordeum vulgare, and in rye, Secale cereale, seven in Brachypodium distachyon, and six in rice, Oryza sativa. The analysis of gene expression was assayed in triticale and rye by RNA-Seq analysis of 454 sequence sets and members of the gene family were found to have diverse patterns of gene expression in the different tissues that were sampled in rye and in triticale, the hybrid hexaploid species derived from wheat and rye. Expression of the gene family in wheat and barley was also previously determined by microarray analysis, and changes in expression during development and in response to environmental stresses are presented. Conclusions The caleosin gene family had a greater degree of expansion in the Triticeae than in the other monocot species, Brachypodium and rice. The prior implication of one member of the gene family in the stress response and heterotrimeric G protein signaling, points to the potential importance of the caleosin gene family. The complexity of the family and differential expression in various tissues and under conditions of abiotic stress suggests the possibility that caleosin family members may play diverse roles in signaling and development that warrants further investigation

    Reconciling differences in natural tags to infer demographic and genetic connectivity in marine fish populations

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    Processes regulating population connectivity are complex, ranging from extrinsic environmental factors to intrinsic individual based features, and are a major force shaping the persistence of fish species and population responses to harvesting and environmental change. Here we developed an integrated assessment of demographic and genetic connectivity of European flounder Platichthys flesus in the northeast Atlantic (from the Norwegian to the Portuguese coast) and Baltic Sea. Specifically, we used a Bayesian infinite mixture model to infer the most likely number of natal sources of individuals based on otolith near core chemical composition. Simultaneously, we characterised genetic connectivity via microsatellite DNA markers, and evaluated how the combined use of natural tags informed individual movement and long-term population exchange rates. Individual markers provided different insights on movement, with otolith chemistry delineating Norwegian and Baltic Sea sources, whilst genetic markers showed a latitudinal pattern which distinguished southern peripheral populations along the Iberian coast. Overall, the integrated use of natural tags resulted in outcomes that were not readily anticipated by individual movement or gene flow markers alone. Our ecological and evolutionary approach provided a synergistic view on connectivity, which will be paramount to align biological and management units and safeguard species’ biocomplexityFundação para a Ciência e a Tecnologia | Ref. UID/MAR/04292/2013Fundação para a Ciência e a Tecnologia | Ref. PTDC/AAG-GLO/5849/2014Fundação para a Ciência e a Tecnologia | Ref. PTDC/MAR-EST/2098/201

    Wheat EST resources for functional genomics of abiotic stress

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    BACKGROUND: Wheat is an excellent species to study freezing tolerance and other abiotic stresses. However, the sequence of the wheat genome has not been completely characterized due to its complexity and large size. To circumvent this obstacle and identify genes involved in cold acclimation and associated stresses, a large scale EST sequencing approach was undertaken by the Functional Genomics of Abiotic Stress (FGAS) project. RESULTS: We generated 73,521 quality-filtered ESTs from eleven cDNA libraries constructed from wheat plants exposed to various abiotic stresses and at different developmental stages. In addition, 196,041 ESTs for which tracefiles were available from the National Science Foundation wheat EST sequencing program and DuPont were also quality-filtered and used in the analysis. Clustering of the combined ESTs with d2_cluster and TGICL yielded a few large clusters containing several thousand ESTs that were refractory to routine clustering techniques. To resolve this problem, the sequence proximity and "bridges" were identified by an e-value distance graph to manually break clusters into smaller groups. Assembly of the resolved ESTs generated a 75,488 unique sequence set (31,580 contigs and 43,908 singletons/singlets). Digital expression analyses indicated that the FGAS dataset is enriched in stress-regulated genes compared to the other public datasets. Over 43% of the unique sequence set was annotated and classified into functional categories according to Gene Ontology. CONCLUSION: We have annotated 29,556 different sequences, an almost 5-fold increase in annotated sequences compared to the available wheat public databases. Digital expression analysis combined with gene annotation helped in the identification of several pathways associated with abiotic stress. The genomic resources and knowledge developed by this project will contribute to a better understanding of the different mechanisms that govern stress tolerance in wheat and other cereals

    Toward spatial fit in the governance of global commodity flows

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    Unidad de excelencia María de Maeztu CEX2019-000940-MGlobal commodity flows between distally connected social-ecological systems pose important challenges to sustainability governance. These challenges are partly due to difficulties in designing and implementing governance institutions that fit or match the scale of the environmental and social problems generated in such telecoupled systems. We focus on the spatial dimension of governance fit in relation to global commodity flows and telecoupled systems. Specifically, we draw on examples from land use and global agricultural commodity governance to examine two overarching types of governance mismatches: boundary mismatches and resolution mismatches. We argue that one way to address mismatches is through governance rescaling and illustrate this approach with reference to examples of three broad types of governance approaches: trade agreements, due diligence laws, and landscape approaches to supply chain governance. No single governance approach is likely to address all mismatches, highlighting the need to align multiple governance approaches to govern telecoupled systems effectively
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