In PLoS Genetics this week, a team of researchers from China report the regulation and function of miR-218 in gastric cancer metastasis. Jun Tie et al. describe a negative feedback system between Robo1, a Slit receptor, and miR-218. "Decreased miR-218 levels eliminate Robo1 repression, which activates the Slit-Robo1 pathway through the interaction between Robo1 and Slit2, thus triggering tumor metastasis," the authors write, suggesting that the restoration of miR-218 suppresses Robo1 expression and inhibits tumor cell invasion.
In PLoS One this week, a pair of researchers in New Zealand report their testing of the metabolic rate hypothesis, wherein mtDNA evolutionary rates are mediated primarily by the mutagenic byproducts of respiration in the springtail Cryptopygus antarcticus travei. Using Bayesian analysis and comparative phylogenetics, the authors' study did not produce "significant evidence that contemporary metabolic rates directly correlate with mutation rate," they write. Further, the authors provide suggestions for further intra-specific studies, such as their own, which could be improved by accounting for oxidative stress effects, among other things.
Also in PLoS ONE, researchers at the University of Southern California and the University of Minnesota describe their examination of the association between the prevalence of cardiovascular disease and peripheral blood leukocytes genomic DNA methylation; they found elevated, rather than decreased, PBL DNA methylation to be positively associated with the prevalence of CVD, obesity and other predisposing conditions in a Singapore Chinese population.
Researchers describe their elucidation of widespread gene conversion in centromere cores in PLoS Biology this week. Using a novel approach — their CENH3 ChIP display method, which maps the kinetochore footprints over transposon-rich areas of centromere cores — the team mapped a total of 238 within-centromere markers in a maize recombinant inbred line. They found that more than half of the markers directly interact with the kinetochores using chromatin immunoprecipitation. The authors postulate that historical gene conversion is widespread in maize centromeres. They "conclude that gene conversion accelerates centromere evolution by facilitating sequence exchange among chromosomes."