In Science this week, investigators at the Whitehead Institute show that adult pluripotent stem cells called clonogenic neoblasts "underlie the remarkable regenerative abilities of planarians." All dividing cNeoblasts, the authors write, express the smedwi-1 gene and "display [a] broad differentiation capacity." Further, in its functional analysis, the Whitehead team found that transplanting single cNeoblasts into lethally irradiated hosts restored their regeneration.
Researchers at the University of Washington in Seattle and at the Scripps Research Institute in La Jolla, Calif., describe a "general computational method for designing proteins that bind a surface patch of interest on a target macromolecule," which they say may be useful for the design of diagnostics and therapeutics. In its paper in this week's Science, the UW-Scripps team reports its de novo modeling of protein-protein interactions to design high-affinity binders to the conserved stem region on hemagglutinin, which it says is a prime candidate for influenza therapies.
In another paper appearing in this week's issue, an international team led by investigators at Japan's National Institute of Genetics in Shizuoka reports a "role for pi[PIWI-interacting]RNAs and non-coding RNA in de novo DNA methylation of the imprinted mouse Rasgrf1 locus." In addition, the team shows that components of the piRNA pathway are not required for de novo methylation of the differentially methylated region at any other paternally imprinted loci. In its Science paper, the team suggests a "model in which piRNAs and a target RNA direct the sequence-specific methylation of Rasgrf1."
Investigators at Johns Hopkins University and at the Malaria Institute at Macha in Choma, Zambia, report on an Enterobacter bacterium they isolated from wild mosquito populations in Zambia "that renders the mosquito resistant to infection with the human malaria parasite Plasmodium falciparum by interfering with parasite development before invasion of the midgut epithelium." In its phenotypic analyses, the team found that the Enterobacter's anti-Plasmodium mechanism "requires small populations of replicating bacteria and is mediated through a mosquito-independent interaction with the malaria parasite."