Catálogo de publicaciones - revistas

<jats:title>Signs of a metabolon in action</jats:title> <jats:p> Eukaryotic cells have a heterogeneous cytoplasm, with compartments large and small, membrane bound or not. Enzymes that catalyze the de novo synthesis of purine nucleotides, which are needed in rapidly dividing cells, are known to assemble into loosely associated, multienzyme structures called purinosomes, but the extent to which these structures are metabolically active has been less certain. Pareek <jats:italic>et al.</jats:italic> performed metabolomics to trace how purines are synthesized within purinosomes and used sophisticated mass spectrometry imaging to directly observe hotspots of metabolic activity within frozen HeLa cells (see the Perspective by Alexandrov). They found evidence for metabolic channeling between enzymes, which limits equilibration of intermediates formed in purinosomes with the bulk cellular metabolite pool. This process occurs specifically within purinosomes associated with mitochondria, because the input metabolites, glycine, aspartate, and formate, come from mitochondrial metabolism. Such channeling may help cells control the ratio and abundance of purine nucleotides. </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="6488" page="283" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.aaz6465">283</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6488" page="241" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.abb3094">241</jats:related-article> </jats:p>

<jats:title>A PAMless base editor</jats:title> <jats:p> CRISPR-Cas DNA base editing typically requires a specific motif for targeting known as a protospacer-adjacent motif (PAM). This requirement limits the sequences within a genome that can be targeted. Walton <jats:italic>et al.</jats:italic> engineered specific variants of the <jats:italic>Streptococcus pyogenes</jats:italic> Cas9 enzyme named SpG and SpRY that could recognize and edit a wider array of PAMs. Using SpRY, the authors were able to correct previously uneditable mutations associated with human disease. Although off-target effects were observed for these engineered Cas enzymes at levels similar to those of the wild-type enzyme, depending on the context, these engineered enzymes widen the potential applications of precision genome editing. </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="6488" page="290" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.aba8853">290</jats:related-article> </jats:p>

<jats:title>Delivering methane and hydrogen</jats:title> <jats:p> The pressure for onboard storage of methane and hydrogen on vehicles is usually limited to 100 bar for the use of lightweight containers, but the amount stored can be increased with the use of absorbent materials. Efficient storage and delivery require a balance of volumetric and gravimetric storage. Chen <jats:italic>et al.</jats:italic> designed a metal-organic framework with trialuminum nodes and a large hexadentate aromatic linker that optimizes both parameters. This material surpassed the U.S. Department of Energy targets for methane and had a deliverable capacity of 14% by weight for hydrogen. </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="6488" page="297" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.aaz8881">297</jats:related-article> </jats:p>

<jats:title>How egg temperature sets sex</jats:title> <jats:p> In many reptiles, sex is determined by nest temperature during egg incubation. Temperature regulates the expression of an epigenetic modifier gene called <jats:italic>Kdm6b</jats:italic> , which is responsible for testis development. However, the molecular connection between temperature and sex-specific expression of this factor was previously unknown. Weber <jats:italic>et al.</jats:italic> have identified a link between temperature and the activation of a key regulator of <jats:italic>Kdm6b</jats:italic> called signal transducer and activator of transcription 3 (STAT3). After an influx of Ca <jats:sup>2+</jats:sup> at the warmer, female-producing temperature, STAT3 is phosphorylated and silences <jats:italic>Kdm6b</jats:italic> transcription to repress testis development. </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="6488" page="303" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.aaz4165">303</jats:related-article> </jats:p>