Catálogo de publicaciones - revistas

<jats:title>Resisting the Chop</jats:title> <jats:p> Dengue, West Nile, and Yellow Fever viruses are all flaviviruses that have single-stranded RNA genomes and form specific, short flaviviral RNAs (sfRNAs) during infection that cause viral pathogenicity. These sfRNAs are produced by the incomplete degradation of viral RNA by the host-cell exonuclease Xrn1. What stops the host enzyme from completely chopping up the viral RNA? <jats:bold> Chapman <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6181" page="307" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1250897">307</jats:related-article> ) reveal a pseudoknot in the structure of the Xrn1-resistant segment of a sfRNA from Murray Valley Encephalitis Virus, which, perhaps, the host Xrn1 exonuclease cannot untangle. </jats:p>

<jats:title>L[i]nc to Dendritic Cell Activation</jats:title> <jats:p> Long noncoding RNAs (lncRNAs) are important regulators of gene expression, but whether they are important regulators of the immune system is poorly understood. <jats:bold> Wang <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6181" page="310" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1251456">310</jats:related-article> ) identify a lncRNA expressed exclusively in human dendritic cells (DC), called lnc-DC, that is required for optimal DC differentiation from human monocytes and that regulates DC activation of T cells. Lnc-DC interacts with the transcription factor STAT3, which is also required for DC development and function, to prevent interaction with and to block dephosphorylation by tyrosine phosphatase SHP1. </jats:p>

<jats:title>Resilient Hyperpolarization</jats:title> <jats:p> Despite constant exposure to all sorts of stressors, most people are resilient and do not develop depression, but we do not understand the neurophysiological underpinnings of stress resilience. <jats:bold> Friedman <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6181" page="313" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1249240">313</jats:related-article> ) studied this phenomenon in a mouse model of social-defeat stress depression. In the mice they found that, despite apparently pathological levels of hyperpolarization and elevated potassium channel currents in the ventral tegmental area (a structure known to be involved in depression), resilient mice showed normal activity in dopaminergic neurons. Thus, if “depressed” mice were experimentally provoked into hyperpolarization—unexpectedly, they completely reversed depression-related behaviors. </jats:p>

<jats:title>Patchy Insulation</jats:title> <jats:p> Myelin insulates neuronal axons such that their electrical signals travel faster and more efficiently. However, not all axons are myelinated equally. <jats:bold> Tomassy <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6181" page="319" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1249766">319</jats:related-article> ; see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6181" page="264" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1253851">Fields</jats:related-article> </jats:bold> ) obtained detailed images from two snippets of the adult mouse brain and generated three-dimensional reconstructions of individual neurons and their myelination patterns. The images show that some axons have long, unmyelinated stretches, which might offer sites for building new connections. Thus, myelination is not an all-or-none phenomenon but rather is a characteristic of what may be a specific dialogue between the neuron and the surrounding myelin-producing cells. </jats:p>

<jats:p>On this week's show: observation of a distinctive binary-star system that includes a white dwarf and a roundup of stories from our daily news site.</jats:p>

<jats:p>A weekly roundup of information on newly offered instrumentation, apparatus, and laboratory materials of potential interest to researchers.</jats:p>