Catálogo de publicaciones - revistas

<jats:title>How dipeptide repeats cause pathology</jats:title> <jats:p> A repeat expansion in the chromosome 9 open reading frame 72 ( <jats:italic>C9orf72</jats:italic> ) gene is the most common known cause of two neurodegenerative diseases: frontotemporal dementia and amyotrophic lateral sclerosis. This expansion leads to the abnormal production of proteins of repeating dipeptides, but their contribution to disease pathogenesis remains unclear. Zhang <jats:italic>et al.</jats:italic> engineered a mouse model to study the consequences of one of these dipeptides—prolinearginine dipeptide repeat protein, poly(PR)—in the brain. They found that poly(PR) caused neuron loss as well as motor and memory impairments. These detrimental effects resulted from poly(PR)-induced perturbation of heterochromatin function, a tightly packed form of DNA that represses gene expression. </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.aav2606">eaav2606</jats:related-article> </jats:p>

<jats:title>The ultimate in thin-film magnetism</jats:title> <jats:p>The alignment of the magnetic properties of atoms gives rise to a wealth of simple and exotic properties that can be exploited. As the dimension of the material is reduced, such that the atoms are in a single monolayer, it was widely believed that thermal fluctuations overwhelm and prevent magnetic ordering. Gong and Zhang review the developments that have followed the recent discovery of magnetism in two-dimensional materials. Recognizing that magnetic anisotropy can be used to induce stable magnetism in atomic monolayers, they provide an overview of the materials available and the physical understanding of the effects and then discuss how these effects could be exploited for widespread practical applications.</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.aav4450">eaav4450</jats:related-article> </jats:p>

<jats:title>The machinery behind amyloid peptides</jats:title> <jats:p> β-Amyloid peptides, which are derived from amyloid precursor protein (APP), form the plaques in the brain that are characteristic of Alzheimer's disease. Zhou <jats:italic>et al.</jats:italic> report a high-resolution structure of a transmembrane segment of APP bound to human γ-secretase, the transmembrane protease that cleaves APP to give β-amyloid peptides (see the Perspective by Lichtenthaler and Güner). Disease-associated mutations within presenilin-1, the catalytic subunit of APP, likely affect how the substrate is bound and thus which peptides are generated, with some being more amyloidogenic. It may now be possible to exploit the features of substrate binding to design inhibitors. </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.aaw0930">eaaw0930</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6428" page="690" related-article-type="in-this-issue" vol="363" xlink:href="10.1126/science.aaw5547">690</jats:related-article> </jats:p>

<jats:title>Bacterial warhead targets DNA</jats:title> <jats:p> The bacterial toxin colibactin causes double-stranded DNA breaks and is associated with the occurrence of bacterially induced colorectal cancer in humans. However, isolation of colibactin is difficult, and its mode of action is poorly understood. Wilson <jats:italic>et al.</jats:italic> studied <jats:italic>Escherichia coli</jats:italic> that contain the biosynthetic gene island called <jats:italic>pks</jats:italic> , which is associated with colibactin production (see the Perspective by Bleich and Arthur). They identified the DNA adducts that resulted from incubating <jats:italic>pks</jats:italic> <jats:sup>+</jats:sup> <jats:italic>E. coli</jats:italic> in human cells. To overcome the lack of colibactin for direct analysis, mimics of the <jats:italic>pks</jats:italic> product were synthesized. From the resulting synthetic adenine-colibactin adducts, it became evident that alkylation via a cyclopropane “warhead” breaks the DNA strands. Similar DNA adducts were then identified in the gut epithelia of mice infected with <jats:italic>pks</jats:italic> <jats:sup>+</jats:sup> <jats:italic>E. coli.</jats:italic> </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.aar7785">eaar7785</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6428" page="689" related-article-type="in-this-issue" vol="363" xlink:href="10.1126/science.aaw5475">689</jats:related-article> </jats:p>

<jats:p>Science is a global endeavor that affects well-being and stability on many fronts, so anything that damages the scientific enterprise in one country, particularly a powerhouse that is internationally networked, damages conditions everywhere. As the United Kingdom tumbles toward the 29 March Brexit deadline, the world should feel uneasy, at the very least. Paradoxically, science has never been high on the Brexit agenda likely because there is general agreement among politicians on all sides that good science relations are in everyone's best interest. Thus, the United Kingdom does not have a plan in place for preserving science. Everyone who cares about the future of science needs to continue to make the case for the smoothest transition on 29 March—whether there is a deal or not—so that U.K. science and global science do not become accidental victims.</jats:p>

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

<jats:p>Recent memos describe crackdown on grantees and on lab scientists with foreign ties.</jats:p>

<jats:p>Critics complain of lack of transparency in decision that allows efforts to create potentially risky virus strains.</jats:p>

<jats:p>War and distrust of vaccines seeded ongoing outbreak</jats:p>