Catálogo de publicaciones - revistas

<jats:title>An antiviral Dicer defends stem cells</jats:title> <jats:p> Stem cells have a pivotal role in maintaining tissue architecture, integrity, and renewal. Poirier <jats:italic>et al.</jats:italic> demonstrate that mammalian stem cells can protect themselves from some RNA viruses by expressing an alternatively spliced isoform of the enzyme Dicer called aviD, which potentiates antiviral RNA interference (see the Perspective by Shahrudin and Ding). aviD acts by cleaving long, base-paired viral RNAs to generate small interfering RNAs that direct the sequence-specific cleavage of homologous viral RNAs. This process is reminiscent of that in insects and worms, which also use Dicer-dependent RNA interference in antiviral defense, and contrasts with mammalian differentiated cells, which generally rely on the interferon system to combat virus infection. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , abg2264, this issue p. <jats:related-article issue="6551" page="231" related-article-type="in-this-issue" vol="373">231</jats:related-article> ; see also abj5673, p. <jats:related-article issue="6551" page="160" related-article-type="in-this-issue" vol="373">160</jats:related-article> </jats:p>

<jats:title>Mind your metals</jats:title> <jats:p> Iron–sulfur clusters are important cofactors for proteins involved in metabolism and electron transfer but are also sometimes found in enzymes involved in transcription and replication of DNA. In vitro expression of such enzymes can result in faulty cluster assembly and confusion about the composition of the functional enzyme. Using a careful anoxic purification scheme, Maio <jats:italic>et al.</jats:italic> found that the severe acute respiratory syndrome coronavirus 2 RNA–dependent RNA polymerase contains two iron–sulfur clusters at two sites previously observed to bind zinc ions. Mutation of the ligating cysteine residues resulted in loss of polymerase activity. A less severe loss of activity was seen in the zinc-containing enzyme. Treatment with the nitroxide drug TEMPOL resulted in degradation of the clusters, enzyme inhibition, and inhibition of viral replication in cell culture. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , abi5224, this issue p. <jats:related-article issue="6551" page="236" related-article-type="in-this-issue" vol="373">236</jats:related-article> </jats:p>

<jats:title>Representing space in past and future</jats:title> <jats:p>As an organism moves through space, its brain has to remember its most recent location and anticipate its future position, not just its current place in the world. Earlier studies reported so-called retrospective and prospective place coding in rats while they were running along linear tracks. However, it would be advantageous to study an animal that rapidly moves through three-dimensional space with high precision. Dotson and Yartsev recorded from flying bats to investigate whether place cell activity in hippocampus area CA1 represents local (current) or nonlocal positions. They discovered that the hippocampus not only encodes the bat's present location but also signals its positions in the past and future.</jats:p> <jats:p> <jats:italic>Science</jats:italic> , abg1278, this issue p. <jats:related-article issue="6551" page="242" related-article-type="in-this-issue" vol="373">242</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>