Catálogo de publicaciones - revistas

<jats:title>Dephosphorylating RNA molecules</jats:title> <jats:p> Transfer RNA (tRNA) and messenger RNA molecules often acquire a terminal 2′,3′-cyclic phosphate group when processed in the cell. These cyclic phosphates provide attachment points for tRNA ligases and must be removed to recycle tRNAs from stalled ribosomes. Pinto <jats:italic>et al.</jats:italic> identified an enzyme from human tissue culture cells that can do the job. Biochemical characterization and analysis of a crystal structure reveal ANGEL2 as a 2′,3′-cyclic phosphatase with functions for RNA processing and modification. </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="6503" page="524" related-article-type="in-this-issue" vol="369" xlink:href="10.1126/science.aba9763">524</jats:related-article> </jats:p>

<jats:title>The development of microglia</jats:title> <jats:p> Microglia are the brain's immune cells, and they play important roles in health and neurodegenerative disease. Kracht <jats:italic>et al.</jats:italic> performed single-cell analysis of human microglial gene expression and chromatin accessibility and compared the results with those of other studies of human and mice microglial development. By using in situ validation, these data identify fetal microglial subsets that appear to be distinct from adult human microglia, suggesting functional differences between the developing and mature brain. </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="6503" page="530" related-article-type="in-this-issue" vol="369" xlink:href="10.1126/science.aba5906">530</jats:related-article> </jats:p>

<jats:title>Reactions give solvents a kick</jats:title> <jats:p> During a chemical reaction, the reorganization of solvent molecules not directly in contact with reactants and products is normally viewed as a simple diffusion response. Wang <jats:italic>et al.</jats:italic> studied molecular diffusion in six common reactions—including the copper-catalyzed click reaction and the Diels-Alder reaction—with pulsed-field gradient nuclear magnetic resonance. They observed a boost in mobility relative to Brownian diffusion that was stronger for the catalyzed reactions that were studied. The mobilities for the click reaction were verified with a microfluidic gradient method. They argue that energy release produces transient translational motion of reacting centers that mechanically perturbs solvent molecules. </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="6503" page="537" related-article-type="in-this-issue" vol="369" xlink:href="10.1126/science.aba8425">537</jats:related-article> </jats:p>

<jats:title>Deformable semiconductors</jats:title> <jats:p> Semiconductors are usually brittle and do not deform easily. Wei <jats:italic>et al.</jats:italic> found that bulk single crystals of indium selenide instead have excellent flexibility (see the Perspective by Han). The deformability comes from the compliant intralayer bonding between indium and selenium. The authors used these observations along with a previously discovered silver sulfide to determine a deformability factor for materials that may help find other deformable semiconductors. </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="6503" page="542" related-article-type="in-this-issue" vol="369" xlink:href="10.1126/science.aba9778">542</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6503" page="509" related-article-type="in-this-issue" vol="369" xlink:href="10.1126/science.abd4527">509</jats:related-article> </jats:p>

<jats:title>Neocortex in the fetal brain</jats:title> <jats:p> Along the path of human evolution, gene duplication and divergence produced a protein, ARHGAP11B, that is found in humans but not nonhuman primates or other mammals. Heide <jats:italic>et al.</jats:italic> analyzed the effects of <jats:italic>ARHGAP11B</jats:italic> gene expression, under control of its own human-specific promoter, in the fetal marmoset (see the Perspective by Dehay and Kennedy). In the early weeks of fetal growth, the gene drove greater elaboration of neural progenitors and neocortex than is evident in the normal fetal marmoset. ARHGAP11B expression may be one cause of the more robust neocortex that characterizes the human brain. </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="6503" page="546" related-article-type="in-this-issue" vol="369" xlink:href="10.1126/science.abb2401">546</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6503" page="506" related-article-type="in-this-issue" vol="369" xlink:href="10.1126/science.abd1840">506</jats:related-article> </jats:p>

<jats:title>Lowering the entropy</jats:title> <jats:p> Atoms loaded in an optical lattice can convincingly mimic the behavior of electrons in solids. However, reaching very low temperatures, where the most interesting quantum phases are expected to occur, is tricky. Yang <jats:italic>et al.</jats:italic> introduced a clever experimental technique to reduce the entropy of their sample. They created an array consisting of alternating rows of sample atoms and reservoirs. The entropy was transferred from the sample atoms to the adjacent reservoirs, which were then removed. The resulting low-entropy system can be used as a basis for quantum simulation and information. </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="6503" page="550" related-article-type="in-this-issue" vol="369" xlink:href="10.1126/science.aaz6801">550</jats:related-article> </jats:p>

<jats:title>Integrative in-cell structural biology</jats:title> <jats:p> In bacteria, RNA polymerases can associate with ribosomes to form transcription-translation units called expressomes. Multiple models based on structural data of in vitro reconstitution assays have been proposed for how the two machineries interface with one another. Understanding this bacteria-specific coupling mechanism offers insight regarding the central dogma of molecular biology and might be leveraged for antibiotic development. O'Reilly <jats:italic>et al.</jats:italic> found that the NusA protein interfaces between the two complexes. The authors combined cryo–electron tomography and cross-linking mass spectrometry to produce an integrative model of the transcribing, translating expressome of <jats:italic>Mycoplasma pneumoniae</jats:italic> obtained entirely from in-cell data. This approach contributes to the development of in-cell structural biology. </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="6503" page="554" related-article-type="in-this-issue" vol="369" xlink:href="10.1126/science.abb3758">554</jats:related-article> </jats:p>

<jats:title> Simple swaps of CO <jats:sub>2</jats:sub> </jats:title> <jats:p> The loss of carbon dioxide (CO <jats:sub>2</jats:sub> ) from carboxylic acids is a common reaction in both biochemical and synthetic contexts, but it has generally involved catalysis or prolonged heating. Kong <jats:italic>et al.</jats:italic> now report that certain polar solvents, such as dimethylformamide, promote reversible CO <jats:sub>2</jats:sub> loss all by themselves from carboxylates bridged by one carbon to aromatic rings. With electron-withdrawing substituents on the ring, isotopically labeled CO <jats:sub>2</jats:sub> can be efficiently swapped in even at room temperature. Alternatively, reaction with aldehydes leads to alcohol formation. </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="6503" page="557" related-article-type="in-this-issue" vol="369" xlink:href="10.1126/science.abb4129">557</jats:related-article> </jats:p>

<jats:title>Effects of allele-specific open chromatin</jats:title> <jats:p> Genetic variants in noncoding regions of the genome may underlie the development of disease. However, we are just beginning to tease apart the function of such variants associated with neuropsychiatric disease. Using five types of neural progenitor cells derived from 20 human induced pluripotent stem cell lines, Zhang <jats:italic>et al.</jats:italic> looked at allele-specific open chromatin (ASoC) variants. Many ASoC variants overlapped with genomic elements, such as transcription factor binding sites, and loci identified in genome-wide association studies for neurological traits. From the experimental and computational analyses, they identified single-nucleotide polymorphisms and illuminate how one schizophrenia-associated variant affects neurodevelopment. </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="6503" page="561" related-article-type="in-this-issue" vol="369" xlink:href="10.1126/science.aay3983">561</jats:related-article> </jats:p>