In a paper published online in advance in Science this week, researchers at Harvard Medical School and their colleagues show that in mice the Lynx1 protein "prevents plasticity in the primary visual cortex late in life." The authors report that the loss of Lynx1, a molecular brake, "enhances nicotinic acetylcholine receptor signaling" and add that the expression of this protein "maintains stability of mature cortical networks in the presence of cholinergic innervation." The Harvard-led team suggests that targeting the stasis between excitatory and inhibitory circuits, "which lies at the root of visual plasticity," may prove to be a sound therapeutic target.
A trio of investigators at Yale University describes in this week's Science "how the CCA-adding enzyme selects adenine over cytosine at position 76 of tRNA." In doing so, the team reports "five co-crystal structures of the enzyme complexed with both a tRNA mimic and nucleoside triphosphates," which intimate the mechanistic specificities that govern the association of adenosine 5'-monophosphate with the A76 position of tRNA. Importantly, "discrimination against incorporation of cytidine 5'-triphosphate at position 76 ... prevents the nucleophilic attack by the 3' hydroxyl group of cytidine75," the team reports.
Ana Beloqui at the CSIC Institute of Catalysis in Madrid and her co-authors published a retraction for their October 2009 paper, "Reactome array: forging a link between metabolome and genome." In the paper, the team "described the synthesis of some 2,000 quenched fluorescent dye-metabolite compounds, and their use to create an array to obtain a global overview of the metabolic network operating in a population of cells at the time of sampling." Beloqui et al. write in the retraction that post-publication peer inspections of the paper unmasked errors in the "chemistry underlying array compound synthesis, and the processing of array data obtained."
Science editor-in-chief Bruce Alberts this week expresses his concern over a paper the journal published online in July. Alberts says that genome-wide association study researchers have voiced their concerns over Boston University School of Public Health's Paola Sebastiani and her colleagues' lack of quality-control measures to correct for their use of "a number of different genotyping platforms" in the study in which they report SNP associations for "exceptional longevity in humans". Alberts says that "Science and the authors are taking these concerns seriously" and adds that "Sebastiani et al. have been performing a thorough quality-control analysis on the original raw data as well as generating new data to compare the genotype calls from the 610-Quad array and the other platforms within the same individuals." In addition, they are trying to validate their SNPs using a non-microarray-based genotyping platform.