64,319 research outputs found

    Cooperative Transmission for a Vector Gaussian Parallel Relay Network

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    In this paper, we consider a parallel relay network where two relays cooperatively help a source transmit to a destination. We assume the source and the destination nodes are equipped with multiple antennas. Three basic schemes and their achievable rates are studied: Decode-and-Forward (DF), Amplify-and-Forward (AF), and Compress-and-Forward (CF). For the DF scheme, the source transmits two private signals, one for each relay, where dirty paper coding (DPC) is used between the two private streams, and a common signal for both relays. The relays make efficient use of the common information to introduce a proper amount of correlation in the transmission to the destination. We show that the DF scheme achieves the capacity under certain conditions. We also show that the CF scheme is asymptotically optimal in the high relay power limit, regardless of channel ranks. It turns out that the AF scheme also achieves the asymptotic optimality but only when the relays-to-destination channel is full rank. The relative advantages of the three schemes are discussed with numerical results.Comment: 35 pages, 10 figures, submitted to IEEE Transactions on Information Theor

    Hnrnph1 Is A Quantitative Trait Gene for Methamphetamine Sensitivity.

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    Psychostimulant addiction is a heritable substance use disorder; however its genetic basis is almost entirely unknown. Quantitative trait locus (QTL) mapping in mice offers a complementary approach to human genome-wide association studies and can facilitate environment control, statistical power, novel gene discovery, and neurobiological mechanisms. We used interval-specific congenic mouse lines carrying various segments of chromosome 11 from the DBA/2J strain on an isogenic C57BL/6J background to positionally clone a 206 kb QTL (50,185,512-50,391,845 bp) that was causally associated with a reduction in the locomotor stimulant response to methamphetamine (2 mg/kg, i.p.; DBA/2J < C57BL/6J)-a non-contingent, drug-induced behavior that is associated with stimulation of the dopaminergic reward circuitry. This chromosomal region contained only two protein coding genes-heterogeneous nuclear ribonucleoprotein, H1 (Hnrnph1) and RUN and FYVE domain-containing 1 (Rufy1). Transcriptome analysis via mRNA sequencing in the striatum implicated a neurobiological mechanism involving a reduction in mesolimbic innervation and striatal neurotransmission. For instance, Nr4a2 (nuclear receptor subfamily 4, group A, member 2), a transcription factor crucial for midbrain dopaminergic neuron development, exhibited a 2.1-fold decrease in expression (DBA/2J < C57BL/6J; p 4.2 x 10-15). Transcription activator-like effector nucleases (TALENs)-mediated introduction of frameshift deletions in the first coding exon of Hnrnph1, but not Rufy1, recapitulated the reduced methamphetamine behavioral response, thus identifying Hnrnph1 as a quantitative trait gene for methamphetamine sensitivity. These results define a novel contribution of Hnrnph1 to neurobehavioral dysfunction associated with dopaminergic neurotransmission. These findings could have implications for understanding the genetic basis of methamphetamine addiction in humans and the development of novel therapeutics for prevention and treatment of substance abuse and possibly other psychiatric disorders

    Genome-Wide Identification, Functional Analysis and Expression Profiling of the Aux/IAA Gene Family in Tomato

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    Auxin is a central hormone that exerts pleiotropic effects on plant growth including the development of roots, shoots, flowers and fruit. The perception and signaling of the plant hormone auxin rely on the cooperative action of several components,among which auxin/indole-3-acetic acid (Aux/IAA) proteins play a pivotal role. In this study, we identified and comprehensively analyzed the entire Aux/IAA gene family in tomato (Solanum lycopersicum), a reference species for Solanaceae plants, and the model plant for fleshy fruit development. Functional characterization using a dedicated single cell system revealed that tomato Aux/IAA proteins function as active repressors of auxin-dependent gene transcription, with, however, different Aux/IAA members displaying varying levels of repression. Phylogenetic analysis indicated that the Aux/IAA gene family is slightly contracted in tomato compared with Arabidopsis, with a lower representation of non-canonical proteins. Sl-IAA genes display distinctive expression pattern in different tomato organs and tissues, and some of them display differential responses to auxin and ethylene, suggesting that Aux/IAAs may play a role in linking both hormone signaling pathways. The data presented here shed more light on Sl-IAA genes and provides new leads towards the elucidation of their function during plant development and in mediating hormone cross-talk

    RNA interference knockdown of BRASSINOSTEROID INSENSITIVE1 in maize reveals novel functions for brassinosteroid signaling in controlling plant architecture

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    Brassinosteroids (BRs) are plant hormones involved in various growth and developmental processes. The BR signaling system is well established in Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa) but poorly understood in maize (Zea mays). BRASSINOSTEROID INSENSITIVE1 (BRI1) is a BR receptor, and database searches and additional genomic sequencing identified five maize homologs including duplicate copies of BRI1 itself. RNA interference (RNAi) using the extracellular coding region of a maize zmbril complementary DNA knocked down the expression of all five homologs. Decreased response to exogenously applied brassinolide and altered BR marker gene expression demonstrate that zmbriI-RNAi transgenic lines have compromised BR signaling. zmbriI-RNAi plants showed dwarf stature due to shortened internodes, with upper internodes most strongly affected. Leaves of zmbriI-RNAi plants are dark green, upright, and twisted, with decreased auricle formation. Kinematic analysis showed that decreased cell division and cell elongation both contributed to the shortened leaves. A BRASSINOSTEROID INSENSITIVE1-ETHYL METHANESULFONATE-SUPPRESSOR1-yellow fluorescent protein (BES1-YFP) transgenic line was developed that showed BR-inducible BES1-YFP accumulation in the nucleus, which was decreased in zmbriI-RNAi. Expression of the BES1-YFP reporter was strong in the auricle region of developing leaves, suggesting that localized BR signaling is involved in promoting auricle development, consistent with the zmbriI-RNAi phenotype. The blade-sheath boundary disruption, shorter ligule, and disrupted auricle morphology of RNAi lines resemble KNOTTED1-LIKE HOMEOBOX (KNOX) mutants, consistent with a mechanistic connection between KNOX genes and BR signaling
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