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<jats:title>A foreign-DNA–destroying machine</jats:title> <jats:p> Bacteria have an adaptive immune system, called CRISPR, that identifies invading viruses through their DNA or RNA sequences and cuts them up (see the Perspective by Zhang and Sontheimer). Jackson <jats:italic>et al.</jats:italic> and Mulepati <jats:italic>et al.</jats:italic> have determined the structure of the large protein complex, called Cascade, that targets the invading nucleic acids and does the cutting. The seahorse-shaped structure reveals how the 11 subcomponents of Cascade assemble into the final protein complex. The structure also shows how Cascade presents the short CRISPR-derived RNAs so that they can bind and target foreign DNA. </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="6203" page="1473" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1256328">1473</jats:related-article> and p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6203" page="1479" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1256996">1479</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6203" page="1452" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1260026">1452</jats:related-article> </jats:p>

<jats:title>A foreign-DNA–destroying machine</jats:title> <jats:p> Bacteria have an adaptive immune system, called CRISPR, that identifies invading viruses through their DNA or RNA sequences and cuts them up (see the Perspective by Zhang and Sontheimer). Jackson <jats:italic>et al.</jats:italic> and Mulepati <jats:italic>et al.</jats:italic> have determined the structure of the large protein complex, called Cascade, that targets the invading nucleic acids and does the cutting. The seahorse-shaped structure reveals how the 11 subcomponents of Cascade assemble into the final protein complex. The structure also shows how Cascade presents the short CRISPR-derived RNAs so that they can bind and target foreign DNA. </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="6203" page="1473" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1256328">1473</jats:related-article> and p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6203" page="1479" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1256996">1479</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6203" page="1452" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1260026">1452</jats:related-article> </jats:p>

<jats:title>Aligning a magnetic atomic gas</jats:title> <jats:p> When a bunch of fermions get together, they obey the Pauli exclusion principle: No two fermions can be in the same quantum state. The fermions populate the available states, starting from those lowest in energy. The boundary between the empty and filled states is called the Fermi surface (FS). For cold gases of fermionic atoms in the lab, the FS is usually spherical. Now, Aikawa <jats:italic>et al.</jats:italic> observe the FS squishing in a gas of Er atoms, which behave like tiny magnets and align with their magnetic field environment. The squishing reflects the very directional interactions between the Er atoms. </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="6203" page="1484" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1255259">1484</jats:related-article> </jats:p>

<jats:title>Organic semiconductors go out for a spin</jats:title> <jats:p> Magnetism is a commonly observed phenomenon in the macroscopic world, but its origins lie in the quirky quantum-mechanical property of electrons and certain nuclei known as spin. Recent research has sought to leverage and expand the role of spin in the operation of electronic devices. Malissa <jats:italic>et al.</jats:italic> used a highly sensitive spectroscopic technique to probe, and ultimately manipulate, the subtle effects of spin interactions on the current that flows through organic light-emitting diodes (OLEDs) (see the Perspective by Bobbert). They pinpointed coupling between the spins of the current carriers and the hydrogen nuclei in the hydrocarbon-based material making up the device. </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="6203" page="1487" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1255624">1487</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6203" page="1450" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1259655">1450</jats:related-article> </jats:p>

<jats:title>A carbonyl compound that tips the scales</jats:title> <jats:p> Life is short for the heaviest elements. They emerge from high-energy nuclear collisions with scant time for detection before they break up into lighter atoms. Even <jats:italic>et al.</jats:italic> report that even a few seconds is long enough for carbon to bond to the 106th element, seaborgium (see the Perspective by Loveland). The authors used a custom apparatus to direct the freshly made atoms out of the hot collision environment and through a stream of carbon monoxide and helium. They compared the detected products with theoretical modeling results and conclude that hexacarbonyl Sg(CO) <jats:sub>6</jats:sub> was the most likely structural formula. </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="6203" page="1491" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1255720">1491</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6203" page="1451" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1259349">1451</jats:related-article> </jats:p>

<jats:title>A pathway that controls our mood</jats:title> <jats:p> A brain area called the lateral habenula is involved in negative motivation and may thus play a role in depression. Shabel <jats:italic>et al.</jats:italic> investigated synaptic transmission in a brain pathway to the lateral habenula that transmits disappointment signals. Surprisingly, they found the simultaneous release of two antagonistic substances, glutamate and GABA, from individual nerve cells. In an animal model of depression, GABA release was reduced in this pathway. A widely used antidepressant drug, however, increased GABA co-release. These results reveal an unusual synaptic mechanism that affects lateral habenula activity. This mechanism may be instrumental for regulating the emotional impact of disappointment. </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="6203" page="1494" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1250469">1494</jats:related-article> </jats:p>

<jats:title>Rings of ocean upwelling</jats:title> <jats:p> Coastal upwelling along the coast of California has become more variable than during nearly any period in the past 600 years. Black <jats:italic>et al.</jats:italic> used a 576-year tree ring record to construct a record of wintertime climate along the California coast. Because wintertime climate and coastal upwelling are so closely linked there, they were able to determine that upwelling variability has increased more over the past 60 years than for all but two intervals during that time. The apparent causes of the recent trend appear to be unique, resulting in reduced marine productivity and negative impacts on fish, seabirds, and mammals. </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="6203" page="1498" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1253209">1498</jats:related-article> </jats:p>

<jats:title>The file drawer is full. Should we worry?</jats:title><jats:p>Experiments that produce null results face a higher barrier to publication than those that yield statistically significant differences. Whether this is a problem depends on how many null but otherwise valid results might be trapped in the file drawer. Franco<jats:italic>et al.</jats:italic>use a Time-sharing Experiments in the Social Sciences archive of nearly 250 peer-reviewed proposals of social science experiments conducted on nationally representative samples. They find that only 10 out of 48 null results were published, whereas 56 out of 91 studies with strongly significant results made it into a journal.</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="6203" page="1502" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1255484">1502</jats:related-article></jats:p>

<jats:title>Building connections by gene therapy</jats:title> <jats:p> Voluntary movement requires a molecular conversation between nerves and muscles. This conversation occurs at the neuromuscular junction, a structure where nerves and muscle physically connect. People with diseases characterized by muscle weakness have aberrantly small neuromuscular junctions. Arimura <jats:italic>et al.</jats:italic> used gene therapy to enlarge the neuromuscular junction, which made muscles stronger. Studying mouse models of two distinct neuromuscular disorders, they used an adenovirus vector to deliver <jats:italic>DOK7</jats:italic> , a gene required for formation of the neuromuscular junction. The therapy improved the mice's motor activity and life span. </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="6203" page="1505" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1250744">1505</jats:related-article> </jats:p>

<jats:title>Human adult stem cell expansion</jats:title> <jats:p> Transfused blood saves lives. Despite the widespread use of this critical resource, it is difficult to increase blood cell numbers outside of the body. By screening thousands of small compounds, Fares <jats:italic>et al.</jats:italic> identify a molecule that expands human stem cell numbers in cord blood. The researchers generate many variations of that molecule and show that one such compound provides even greater human blood cell expansion. If researchers can provide increased numbers of stem cells and progenitor cells, cord blood should find even greater use in the clinic. </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="6203" page="1509" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1256337">1509</jats:related-article> </jats:p>