Catálogo de publicaciones - revistas

<jats:title>Turning the tables on microRNA decay</jats:title> <jats:p> MicroRNAs help to regulate many genes in animal cells. Each microRNA associates with an Argonaute (AGO) protein, forming a complex in which the microRNA pairs with a messenger RNA (mRNA) target and AGO recruits factors that accelerate mRNA decay. However, for some unusual targets, the reverse occurs: Pairing to the target recruits factors that accelerate microRNA decay rather than degradation of the mRNA. Working independently, Shi <jats:italic>et al.</jats:italic> and Han <jats:italic>et al.</jats:italic> elucidate the mechanism of this phenomenon. They found that pairing to the unusual targets recruits a ubiquitin ligase that causes degradation of AGO, thereby exposing the microRNA to cellular nucleases. Mutating the ubiquitin ligase in diverse animals and cell types deregulates numerous microRNAs, implying that this phenomenon is widely deployed to sculpt microRNA levels. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" related-article-type="in-this-issue" xlink:href="10.1126/science.abc9359">eabc9359</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" related-article-type="in-this-issue" xlink:href="10.1126/science.abc9546">eabc9546</jats:related-article> </jats:p>

<jats:title>Memory consolidation in the neocortex</jats:title> <jats:p> Information transfer between brain structures located in the medial-temporal lobe and the neocortex is essential for learning. However, the neuronal underpinnings of this transfer are unknown. Doron <jats:italic>et al.</jats:italic> found that neurons located in the deep layers of the perirhinal cortex exhibit increased firing after microstimulation upon learning (see the Perspective by Donato). Learning was associated with the emergence of a small population of neurons in layer 5 of the somatosensory cortex that increased bursting upon stimulation. This increase in bursting was accompanied by an increase in dendritic activity, and silencing the perirhinal cortex to layer 1 projection effectively disrupted learning and its physiological correlates. During learning, perirhinal inputs thus act as a gate for the enhancement of cortico-cortical inputs, which are necessary for stimulus detection and are strengthened during learning. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" related-article-type="in-this-issue" xlink:href="10.1126/science.aaz3136">eaaz3136</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6523" page="1410" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.abf4523">1410</jats:related-article> </jats:p>

<jats:title>A high-quality rhesus macaque genome</jats:title> <jats:p> Genome technology has improved substantially since the first full organismal genomes were generated. Applying new technology, Warren <jats:italic>et al.</jats:italic> refined the genome of the rhesus macaque, a model nonhuman primate. Long-read technology and other recent advances in sequencing technology were applied to generate a genome with far fewer gaps and helped to refine the locations and numbers of repetitive elements. Furthermore, the authors performed resequencing among populations to identify the genetic variability of the rhesus macaque. Thus, a previously incomplete and inaccurate set of sequence information is now fully resolved, improving gene mapping for biomedical and comparative genetic studies. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" related-article-type="in-this-issue" xlink:href="10.1126/science.abc6617">eabc6617</jats:related-article> </jats:p>

<jats:p> Desquilbet <jats:italic>et al</jats:italic> . take issue with our data inclusion criteria and make several other dubious claims regarding data processing, analysis, and interpretation. Most of their concerns stem from disagreement on data inclusion criteria and analysis, misunderstanding of our goals, and unrealistic expectations. We maintain that our synthesis provides a state-of-the-art analysis of patterns of trends in insect abundances. </jats:p>

<jats:title>Splicing machine shifts into gear</jats:title> <jats:p> Spliceosome activation involves extensive protein exchanges and RNA rearrangements that lead to the formation of a catalytically active U2/U6 RNA structure called B <jats:sup>act</jats:sup> . Previously, little was known about the pathway leading to the U2/U6 active site and how proteins aid in folding the U2/U6 RNA. Using cryo–electron microscopy to determine structures of two human pre-B <jats:sup>act</jats:sup> complexes, Townsend <jats:italic>et al.</jats:italic> uncovered an intricate cascade of coordinated structural changes involving mutually exclusive interactions that facilitate the directionality of the activation process. These structures reveal the assembly pathway of the U2/U6 catalytic RNA and the mechanism whereby proteins facilitate its folding. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" related-article-type="in-this-issue" xlink:href="10.1126/science.abc3753">eabc3753</jats:related-article> </jats:p>

<jats:title>Cerebellar evolution</jats:title> <jats:p> Cerebellar nuclei, substructures of the cerebellum, transfer information from the cerebellum to other parts of the brain. Using single-cell transcriptomics, Kebschull <jats:italic>et al.</jats:italic> have now identified a conserved pattern of cerebellar nuclei structure that has been repeated through evolution (see the Perspective by Hatten). Ranging from mice to chickens to humans, cerebellar nuclei are made up of region-specific excitatory neurons and region-invariant inhibitory neurons. In humans, a facet connecting the cerebellum to the frontal cortex is enhanced. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" related-article-type="in-this-issue" xlink:href="10.1126/science.abd5059">eabd5059</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6523" page="1411" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.abf4483">1411</jats:related-article> </jats:p>

<jats:title>Turning the tables on microRNA decay</jats:title> <jats:p> MicroRNAs help to regulate many genes in animal cells. Each microRNA associates with an Argonaute (AGO) protein, forming a complex in which the microRNA pairs with a messenger RNA (mRNA) target and AGO recruits factors that accelerate mRNA decay. However, for some unusual targets, the reverse occurs: Pairing to the target recruits factors that accelerate microRNA decay rather than degradation of the mRNA. Working independently, Shi <jats:italic>et al.</jats:italic> and Han <jats:italic>et al.</jats:italic> elucidate the mechanism of this phenomenon. They found that pairing to the unusual targets recruits a ubiquitin ligase that causes degradation of AGO, thereby exposing the microRNA to cellular nucleases. Mutating the ubiquitin ligase in diverse animals and cell types deregulates numerous microRNAs, implying that this phenomenon is widely deployed to sculpt microRNA levels. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" related-article-type="in-this-issue" xlink:href="10.1126/science.abc9359">eabc9359</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" related-article-type="in-this-issue" xlink:href="10.1126/science.abc9546">eabc9546</jats:related-article> </jats:p>

<jats:p> The buildup to announcing the Breakthrough of the Year is generally a suspenseful time at <jats:italic>Science</jats:italic> . Long meetings are held, spreadsheets are made, and much coffee is consumed. This year, we knew that the breakthrough would involve COVID-19, but it was only in the past few weeks that the highly effective new vaccines would take the crown. For a while, it seemed too much to hope for, but vaccinations are underway at last. </jats:p>

<jats:p>A roundup of weekly science policy and related news.</jats:p>

<jats:p>Advocates call for early vaccination of group made vulnerable by genetics and immune dysfunction.</jats:p>