February 12, 2010
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New Discovery for Neonatal Diabetes: Researchers uncovered an important role for the Rfx6 gene. Its integrity is required for normal development of the islets of Langerhans cells in the pancreas that produces important hormones including insulin. Genetic mutations found in Rfx6 are the cause of severe neonatal diabetes where there are no insulin producing islets of Langerhans cells. To prove the critical role of Rfx6 in directing the differentiation of early pancreatic cells, researchers disrupted the gene in mice and observed the development of an identical disorder as displayed in humans. Identifying the gene is a key piece of the puzzle and will lead to new avenues to find treatments for all types of diabetes. Dr. Constantin Polychronakos and his team at McGill University collaborated with researchers from UCSF and report their study in the on-line edition of Nature.
Controlling Stem Cell Fate: A genome-wide screen identified the PCL2 (polycomb-like 2) gene as a key decision maker in determining the fate of stem cells. This is an important area of research because stem cell based therapies in regenerative medicine are on the rise but more thorough understanding of stem cell control is necessary for safety reasons. In the absence of PCL2, stem cells can no longer differentiate into specialized cells regardless of adding stimulating factors to try to push it to differentiate. Once they re-introduced PCL2 into the stem cells, they were able to drive differentiation again. By mapping the network of genes that PCL2 regulates, they can trace the steps in the path of a stem cell in becoming one of the many cell types in our body. University of Toronto scientist, Dr. William Stanford and his team describe their research in the journal Cell Stem Cell.
Stem Cell Prediction: This is a neat study. Researchers generated an algorithm to predict the future of a stem cell – whether it divides and self-renew as stem cells or produce alternate cell types. They recorded video of retinal progenitor cells under the microscope to ‘observe’ the cell’s characteristic dynamic behaviour and movements just prior to dividing. This information was computed to generate a predictive algorithm that was tested to be (amazingly!) 99% accurate in identifying cells that will self-renew as stem cells and 87% correct in predicting a differentiation cell fate. This may lead to new tools to help scientists isolate pure populations of stem cells for their future studies. Dr. Michel Cayouette’s group at the Institut de Recherches Cliniques de Montréal presents their work in this week’s edition of Nature Methods.
Genomics of Flesh-eating Disease: The genomic sequences of Streptococcus bacterial strains from past epidemics in Ontario were determined in a study involving Canadian and US researchers. They identified and compared single nucleotide polymorphisms (SNPs) between the strains and found that they were different by an average of only 49 SNPs. Each strain, however, also contained unique sequences that could be used for tracking purposes in future outbreaks. Some genes were highly variable, which is information that they can use to try to understand the bacterial virulence factors at play in gaining an advantage over the infected person. These comparative pathogenomic studies are invaluable for microbial epidemiology research and for shedding light on new potential targets for antibiotic drugs. Drs. Donald Low and Allison McGeer at Mount Sinai Hospital participated in the research that is reported in this week’s edition of the Proceedings of The National Academy of Sciences.