Catálogo de publicaciones - revistas

<jats:title>Dormancy by communication shutdown</jats:title> <jats:p> Trees become dormant in winter, with encapsulated buds protected against harsh conditions. Tylewicz <jats:italic>et al.</jats:italic> found that, as the days get shorter, communication channels between cells in aspen trees shut down. The blocked plasmodesmata sequester the dormant meristems from growth signals. Growth-promoting signals can be turned on and off relatively rapidly, but the closed plasmodesmata are not so nimble. Thus, despite the occasional sunny day, the trees stay dormant until spring. </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" issue="6385" page="212" related-article-type="in-this-issue" vol="360" xlink:href="10.1126/science.aan8576">212</jats:related-article> </jats:p>

<jats:title>A close-up view of oligosaccharyltransferase</jats:title> <jats:p> Many secretory and membrane proteins are modified through the attachment of sugar chains by N-glycosylation. Such modification is required for correct protein folding, targeting, and functionality. In mammalian cells, N-glycosylation is catalyzed by the oligosaccharyltransferase (OST) complex via its STT3 subunit. OST forms a complex with the ribosome and the Sec61 protein translocation channel. Braunger <jats:italic>et al.</jats:italic> combined cryo–electron microscopy approaches to visualize mammalian ribosome-Sec61-OST complexes in order to build an initial molecular model for mammalian OST. </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" issue="6385" page="215" related-article-type="in-this-issue" vol="360" xlink:href="10.1126/science.aar7899">215</jats:related-article> </jats:p>

<jats:title>The RNA exosome captured in action</jats:title> <jats:p> The RNA exosome, a major RNA degradation machine, processes ribosomal RNA (rRNA) precursors and is directly coupled to the protein synthesis machine, the ribosome. Using cryo–electron microscopy, Schuller <jats:italic>et al.</jats:italic> investigated the structure of the precursor large ribosomal subunit from yeast with unprocessed rRNA in complex with the RNA exosome. The structure captures a snapshot of two molecular machines transiently interacting and explains how the RNA exosome acts on an authentic physiological substrate and remodels the large subunit during ribosome maturation. </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" issue="6385" page="219" related-article-type="in-this-issue" vol="360" xlink:href="10.1126/science.aar5428">219</jats:related-article> </jats:p>

<jats:title>Autoantibody redemption through rapid mutations</jats:title> <jats:p> Antibodies distinguish foreign epitopes from closely related self-antigens by poorly understood mechanisms. In mice, Burnett <jats:italic>et al.</jats:italic> found that a proportion of B cells could cross-react with similar foreign and self-antigens (see the Perspective by Kara and Nussenzweig). Challenge with self-antigen resulted in anergy (i.e., a lack of immune response), which was reversed by exposure to high-density foreign antigen. Mutations that decreased self-affinity were rapidly selected for, whereas selection for epistatic mutations that enhanced foreign reactivity took longer. Self-reactivity, rather than being an impediment to immunization, resulted in higher affinities against a foreign immunogen. </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" issue="6385" page="223" related-article-type="in-this-issue" vol="360" xlink:href="10.1126/science.aao3859">223</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6385" page="152" related-article-type="in-this-issue" vol="360" xlink:href="10.1126/science.aat5758">152</jats:related-article> </jats:p>

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