Catálogo de publicaciones - revistas

<jats:title>Phage Invasion</jats:title> <jats:p> Bacteriophages are responsible for much of bacterial evolution, both by imposing selection for resistance to infection and by horizontal gene transfer of host genes to new bacteria. However, we know surprisingly little about the initiation of phage infection. <jats:bold> Hu <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="576" related-article-type="in-this-issue" vol="339" xlink:href="10.1126/science.1231887">576</jats:related-article> , published online 10 January) used high-throughput cryo-electron tomography and sub-volume analysis to examine <jats:italic>Escherichia coli</jats:italic> minicells infected with both wild-type and mutant T7 bacteriophages. High-resolution views of phage structures at different stages of infection reveal the de novo formation of an extended tail by the ejection of internal head proteins, in order to form the channel for DNA transport into the cytoplasm. </jats:p>

<jats:title>Cells in Transit(ion)</jats:title> <jats:p> Epithelial-mesenchymal transition (EMT) is a developmental program that converts adherent epithelial cells to a migratory mesenchymal state. This cell-fate change has been linked to tumor metastasis in preclinical models. To investigate whether EMT occurs in human cancer, <jats:bold> Yu <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="580" related-article-type="in-this-issue" vol="339" xlink:href="10.1126/science.1228522">580</jats:related-article> ) isolated circulating tumor cells (CTCs) from breast cancer patients and analyzed their expression of epithelial and mesenchymal markers by RNA–in situ hybridization and RNA sequencing. Biphenotypic cells expressing both types of markers were rare in primary breast tumors but were enriched among CTCs, as were cells expressing only mesenchymal markers. Serial blood samples from one patient revealed that CTCs in the mesenchymal state declined in number when the patient responded to therapy but rebounded when the disease began to progress—a pattern repeated when a different therapy was administered. Thus, EMT may facilitate tumor cell dissemination in humans. </jats:p>

<jats:title>Modeling Stress</jats:title> <jats:p> Much is known about various factors (transcription and epigenetic factors) involved in gene transcription, but it is difficult to predict expression at a quantitative level. <jats:bold> Neuert <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="584" related-article-type="in-this-issue" vol="339" xlink:href="10.1126/science.1231456">584</jats:related-article> ) developed an integrated experimental and computational procedure to capture, predict, and understand the temporal dynamics of signal-activated gene regulation at single-molecule and single-cell resolution. The approach explores models of varying complexity and uses cross-validation analyses to estimate when models are too simple to be accurate or too complex to be precise. These approaches identify and validate a model that describes and predicts the quantitative messenger RNA dynamics of three genes activated by mitogen-activated protein kinase signaling during cellular stress in yeast. </jats:p>

<jats:title>Dissecting Microtubule Stability</jats:title> <jats:p> Microtubule-stabilizing agents (MSAs), like taxol, inhibit cell division and are widely used in cancer chemotherapy. <jats:bold> Prota <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="587" related-article-type="in-this-issue" vol="339" xlink:href="10.1126/science.1230582">587</jats:related-article> , published online 3 January) present structural data on the molecular mechanism of action of antimitotic drugs. Tubulin structures in complex with the MSAs zampanolide and epothilone A, revealed a general mechanism for how MSAs promote microtubule assembly and stability by affecting lateral tubulin interactions. </jats:p>

<jats:title>Modifying Deubiquitinases</jats:title> <jats:p> Protein ubiquitination is a widespread mechanism for cellular regulation, and new regulators are valuable research tools and may help to generate therapeutic small molecules. <jats:bold> Ernst <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="590" related-article-type="in-this-issue" vol="339" xlink:href="10.1126/science.1230161">590</jats:related-article> , published online 3 January) used known crystal structures to roughly define the interaction domain between a ubiquitin-specific protease and a ubiquitinated substrate and then screened ubiquitin variants with changes in these residues to find variants that acted as potent and specific regulators that could modify ubiquitin pathway regulation in cells. </jats:p>

<jats:p>Listen to stories on the history of carbon cycling, emergent sensing, the Visualization Challenge, and more.</jats:p>

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