Catálogo de publicaciones - revistas

<jats:title>An RNA seed poised to meet its target</jats:title> <jats:p> The CRISPR-Cas system in prokaryotes precisely identifies infecting parasitic DNAs and viruses and destroys them. The CRISPR-Cas system has been adapted for facile genome editing, heralding a new age in molecular biology. Jiang <jats:italic>et al.</jats:italic> show that the Cas9 nuclease adopts a distinct confirmation when it binds to the targeting guide RNA. The guide RNA then assumes a preordered shape. This RNA “seed region” is thus poised to initiate recognition of the DNA target sequence. </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="6242" page="1477" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aab1452">1477</jats:related-article> </jats:p>

<jats:title>Keeping quiet one gene at a time</jats:title> <jats:p> Chromosomal DNA comes in two flavors—euchromatin, which contains most of the expressed genes, and heterochromatin, which usually remains quiet. But what keeps genes within heterochromatin silent? Tchasovnikarova <jats:italic>et al.</jats:italic> examined the basis for this type of silencing in mammalian cells (see the Perspective by Brummelkamp). They identified a complex of proteins in human cells they called HUSH that kept particular parts of the genome silent by changing associated histone methylation marks. </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="6242" page="1481" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aaa7227">1481</jats:related-article> , see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6242" page="1433" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aac6529">1433</jats:related-article> </jats:p>

<jats:title>Unwinding RNA for protein synthesis</jats:title> <jats:p> During the first steps of protein synthesis, the small subunit of the ribosome scans the 5′ end of the mRNA, looking for the protein start codon. This process involves one of the translation initiation factors, eIF4A, which helps to remove any RNA structures that might impede the ribosome's search. García-García <jats:italic>et al.</jats:italic> used single-molecule optical trap assays to show that eIF4A, in combination with two other translation initiation factors, is able to continuously and directionally unwind a double-stranded RNA hairpin. The factors unwound RNA in steps roughly equal to a turn of the RNA double helix. </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="6242" page="1486" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aaa5089">1486</jats:related-article> </jats:p>

<jats:title>Multitasking around the clock</jats:title> <jats:p> Chronic disruption of our circadian rhythms—for example, through shift work—may increase the risk of metabolic disease. Zhang <jats:italic>et al.</jats:italic> found that a multitasking transcription factor called Rev-erb-α regulates expression of both clock and metabolic genes through distinct mechanisms. At clock genes, it binds directly to a specific DNA sequence, displacing a competing transcription factor. At metabolic genes, it interacts not with DNA but with other transcription factors that regulate metabolic gene expression in a tissue-specific manner. </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="6242" page="1488" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aab3021">1488</jats:related-article> </jats:p>

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

<jats:p>On this week's show: Making metallic hydrogen and a roundup of daily news stories.</jats:p>