Catálogo de publicaciones - revistas

<jats:p>On this week's show: Culturing the cruise-ship disease and a news roundup.</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>DNA double-strand breaks (DSBs) are introduced in meiosis to initiate recombination and generate crossovers, the reciprocal exchanges of genetic material between parental chromosomes. Here, we present high-resolution maps of meiotic DSBs in individual human genomes. Comparing DSB maps between individuals shows that along with DNA binding by PRDM9, additional factors may dictate the efficiency of DSB formation. We find evidence for both GC-biased gene conversion and mutagenesis around meiotic DSB hotspots, while frequent colocalization of DSB hotspots with chromosome rearrangement breakpoints implicates the aberrant repair of meiotic DSBs in genomic disorders. Furthermore, our data indicate that DSB frequency is a major determinant of crossover rate. These maps provide new insights into the regulation of meiotic recombination and the impact of meiotic recombination on genome function.</jats:p>

<jats:p>Most vertebrate organs are composed of epithelium surrounded by support and stromal tissues formed from mesenchyme cells, which are not generally thought to form organized progenitor pools. Here, we use clonal cell labeling with multicolor reporters to characterize individual mesenchymal progenitors in the developing mouse lung. We observe a diversity of mesenchymal progenitor populations with different locations, movements, and lineage boundaries. Airway smooth muscle (ASM) progenitors map exclusively to mesenchyme ahead of budding airways. Progenitors recruited from these tip pools differentiate into ASM around airway stalks; flanking stalk mesenchyme can be induced to form an ASM niche by a lateral bud or by an airway tip plus focal Wnt signal. Thus, mesenchymal progenitors can be organized into localized and carefully controlled domains that rival epithelial progenitor niches in regulatory sophistication.</jats:p>

<jats:p>Cellular memory is crucial to many natural biological processes and sophisticated synthetic biology applications. Existing cellular memories rely on epigenetic switches or recombinases, which are limited in scalability and recording capacity. In this work, we use the DNA of living cell populations as genomic “tape recorders” for the analog and distributed recording of long-term event histories. We describe a platform for generating single-stranded DNA (ssDNA) in vivo in response to arbitrary transcriptional signals. When coexpressed with a recombinase, these intracellularly expressed ssDNAs target specific genomic DNA addresses, resulting in precise mutations that accumulate in cell populations as a function of the magnitude and duration of the inputs. This platform could enable long-term cellular recorders for environmental and biomedical applications, biological state machines, and enhanced genome engineering strategies.</jats:p>

<jats:p>The 2014 mid-term elections are over, and at least 62 new members of the U.S. Congress will be taking office on 3 January 2015. Many will be accompanied by new staff, not all of them familiar with science and science policy. Compounding the ambiguity that always comes with new legislators is that the leadership of the Senate has changed from Democratic to Republican. It is as yet unknown where the new leaders and committee chairs will stand on science policy issues, but so far, science has not been declared among the priorities put forward by either party. All of this is taking place just as many of science's long-time legislative champions are retiring. Overall research and development spending has already fallen 16% in inflation-adjusted dollars from fiscal year (FY) 2010 to the FY 2015 budget request. The federal government's investment in science and technology now stands at roughly 0.78% of the economy, the lowest point in 50 years. This is the right time for scientists to introduce themselves to their new legislators, congratulate them on their election, offer their services if needed on policy matters that would benefit from science input, and emphasize the importance of science to the country.</jats:p>

<jats:p>A roundup of weekly science policy and related news.</jats:p>

<jats:p>But some still fault scientists for hasty risk assessment.</jats:p>