Catálogo de publicaciones - revistas

<jats:title>Ocular dominance plasticity reconsidered</jats:title> <jats:p> How neuronal circuits are established and reformed during development and learning is unclear. One idea is that cortical circuits have virtually unlimited plasticity and are rebuilt routinely from random components. An alternative view is that some of these connections are more or less preformed and rigid. Working in mice, Rose <jats:italic>et al.</jats:italic> looked at how visual cortical neurons change their response after monocular deprivation. After recovery, the response properties of the neurons returned to their pre-deprivation pattern. Thus, it is not the strong connectivity backbone but perhaps inhibitory and weaker connections that are changed temporarily during sensory deprivation, whereas a core circuitry returns to default mode even after several days of altered activity. </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="6291" page="1319" related-article-type="in-this-issue" vol="352" xlink:href="10.1126/science.aad3358">1319</jats:related-article> </jats:p>

<jats:title>Brain activity to represent the future</jats:title> <jats:p> How do humans navigate from A to B? Brown <jats:italic>et al.</jats:italic> developed a virtual reality task to investigate the neural representations that support human navigational planning. Highly specific activity of the hippocampus and related brain areas represented the future locations to which participants eventually moved. Network-level interactions of the hippocampus with the prefrontal cortex thus enable flexible representation of planned destinations. </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="6291" page="1323" related-article-type="in-this-issue" vol="352" xlink:href="10.1126/science.aaf0784">1323</jats:related-article> </jats:p>

<jats:title>One size does not fit all</jats:title> <jats:p> Oligodendrocytes are best known for their ability to myelinate brain neurons, thus increasing the speed of signal transmission. Marques <jats:italic>et al.</jats:italic> surveyed oligodendrocytes of developing mice and found unexpected heterogeneity. Transcriptional analysis identified 12 populations, ranging from precursors to mature oligodendrocytes. Transcriptional profiles diverged as the oligodendrocytes matured, building distinct populations. One population was responsive to motor learning, and another, with a different transcriptome, traveled along blood vessels. </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="6291" page="1326" related-article-type="in-this-issue" vol="352" xlink:href="10.1126/science.aaf6463">1326</jats:related-article> </jats:p>

<jats:title>Transcription activation all about timing</jats:title> <jats:p> Regulating transcription by RNA polymerase (RNAP) is central to controlling gene expression. Transcription factors influence the activity of the RNAP. Feng <jats:italic>et al.</jats:italic> determined the crystal structure of a bacterial transcription activation complex. The transcription activator protein (TAP) converts the closed RNAP-promoter complex into an open complex through simple stabilizing protein-protein interactions with RNAP. The critical contacts did not go through the RNAP active center or the RNAP clamp. Instead, it seems that the timing of the interaction during transcription complex formation is critical for activation. </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="6291" page="1330" related-article-type="in-this-issue" vol="352" xlink:href="10.1126/science.aaf4417">1330</jats:related-article> </jats:p>

<jats:title>A hit-and-run metal ion</jats:title> <jats:p> DNA polymerase is an enzyme that uses existing DNA as a template to build new DNA by adding new nucleotides to the end of the newly forming daughter strand. The enzyme mechanism that catalyzes formation of a phosphodiester bond is known to require two Mg <jats:sup>2+</jats:sup> ions, and recent crystal structures have shown that a third metal ion is present after bond formation. Gao <jats:italic>et al.</jats:italic> used time-resolved crystallography to visualize bond formation. The enzyme-substrate complex captures a third cation before bond formation occurs, and DNA synthesis cannot occur without the third metal ion. Binding of this metal ion requires thermal motion of the enzyme-substrate complex, so that catalysis is achieved by acquiring a transient cofactor. </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="6291" page="1334" related-article-type="in-this-issue" vol="352" xlink:href="10.1126/science.aad9633">1334</jats:related-article> </jats:p>

<jats:title>Outsourcing cancer immunotherapy</jats:title> <jats:p> Successful cancer immunotherapy depends on a patient's T cells recognizing tumor-specific mutations and then waging a lethal attack. Despite tumors harboring many mutations, most individuals have very few T cells that respond to these so-called “neo-antigens.” Strønen <jats:italic>et al.</jats:italic> isolated T cells from healthy donors that responded to predicted neo-antigens expressed by melanomas taken from three patients, sometimes including neo-antigens that the patient's own T cells ignored (see the Perspective by Yadav and Delamarre). Testing whether such an outsourcing strategy could improve clinical outcomes will be an important next step. </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="6291" page="1337" related-article-type="in-this-issue" vol="352" xlink:href="10.1126/science.aaf2288">1337</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6291" page="1275" related-article-type="in-this-issue" vol="352" xlink:href="10.1126/science.aag1547">1275</jats:related-article> </jats:p>

<jats:title>Altered fluid flow causes curved spine</jats:title> <jats:p> Adolescent idiopathic scoliosis is characterized by three-dimensional spinal curves and affects 3% of the world's children. However, the biological basis of this condition is unclear. Grimes <jats:italic>et al.</jats:italic> studied zebrafish models that likewise display a curved spine. Defects in the formation and function of motile cilia in the central nervous system perturbed the flow of cerebrospinal fluid (CSF), leading to abnormal spinal curvatures as the fish grew. Curves could be partially rescued by restoring CSF flow, suggesting potential therapeutic strategies if the same mechanism is shared in humans. </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="6291" page="1341" related-article-type="in-this-issue" vol="352" xlink:href="10.1126/science.aaf6419">1341</jats:related-article> </jats:p>

<jats:title>A cancer-promoting histone protein</jats:title> <jats:p> Mutations in the chromatin protein histone H3 are found in a number of pediatric cancers. The lysine-36–to–methionine (K36M) “oncohistone” mutation is seen in almost all chondroblastomas. Fang <jats:italic>et al.</jats:italic> show that the K36M mutant histones inhibit the normal methylation of this same residue in wild-type H3 histones. They do so by interfering with the enzymes that normally methylate this residue. The altered chromatin methylation patterns alter the expression of known cancer-related genes and impart cancer-related characteristics to the chondrocyte cells. </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="6291" page="1344" related-article-type="in-this-issue" vol="352" xlink:href="10.1126/science.aae0065">1344</jats:related-article> </jats:p>

<jats:p> For many years, it seems, researchers have had only a limited understanding of cellular communication. That cells could talk to one another via secreted hormones and growth factors was well known. That they also communicate using elaborate vesicular messages written in nucleic acids, proteins, and lipids was not. These vesicles play key roles in both development and disease. Now, researchers are developing new tools and strategies to study them and to exploit their potential in both diagnostics and therapeutics. <jats:list list-type="bullet"> <jats:list-item> <jats:p> <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://www.sciencemag.org/custom-publishing/technology-features/membrane-messengers-extracellular-vesicles">Read the Feature (Full-Text HTML)</jats:ext-link> </jats:p> </jats:list-item> <jats:list-item> <jats:p> <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://www.sciencemag.org/sites/default/files/custom-publishing/documents/10-June-Exosomes.pdf">Read the Feature (PDF)</jats:ext-link> </jats:p> </jats:list-item> <jats:list-item> <jats:p> <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://www.sciencemag.org/sites/default/files/custom-publishing/douments/10%20June%20New%20Products.pdf">Read New Products (PDF)</jats:ext-link> </jats:p> </jats:list-item> </jats:list> </jats:p>

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