Papers To Watch
Solving AMPK
The Scientist Staff | Nov 30, 2007
The enzyme AMP-activated protein kinase (AMPK) has been shown to be central to regulating several metabolic systems such as glucose uptake, oxidation of fatty acids, and insulin sensitivity, but the crystal structure of the mammalian enzyme remained elusive. Bing Xiao and others from the United Kingdom's National Institute for Medical Research used X-ray crystallography to map the structure of AMPK when bound to AMP and ATP, which the enzyme binds competitively,1 illuminating AMPK regul
Papers to watch
The Scientist Staff | Nov 30, 2007
Credit: © James Cavallini / Photo Researchers, Inc." /> Credit: © James Cavallini / Photo Researchers, Inc. J.C. Hermann et al., "Structure-based activity prediction for an enzyme of unknown function," Nature, 448:775-9, Aug. 16, 2007. The X-ray crystallographic structure of the gene product Tm0936 from the amidohydrolase superfamily, deposited by a structural genomics consortium, was used to dock, score, and sort a library of 22,500 high-energy intermediates
Unleashing neurogenesis
The Scientist Staff | Nov 30, 2007
While looking for regulators of neurogenesis, Hongjun Song at Johns Hopkins University School of Medicine and colleagues found that inhibiting the function of the gene disrupted-in-schizophrenia 1 (DISC1) promoted neurogenic behavior.1 The gene is known as a susceptibility gene for mood disorders and schizophrenia, though this was not the focus of Song et al.'s research. They were interested in a previous observation that DISC1 is highly expressed in two areas of the adult brain that
Papers to Watch
The Scientist Staff | Sep 30, 2007
N. Stern-Ginossar, et al., "Host immune system gene targeting by a viral miRNA." Science, 317:376-81, July 20, 2007. Upon infection of its host, human cytomegalovirus (HCMV) expresses a miRNA that directly down-regulates expression of an immunorelated gene, MICB. Thus, it appears that HCMV has developed two distinct mechanisms to down-regulate expression of the same immunorelated gene, with the RNA-based strategy presumably being more ancient. -
Model variation
The Scientist Staff | Sep 30, 2007
Credit: © Dr. Jeremy Burgess / Photo Researchers, Inc." /> Credit: © Dr. Jeremy Burgess / Photo Researchers, Inc. To better understand how evolutionary pressures have helped shape genetic variation in Arabidopsis thaliana, Detlef Weigel from the Salk Institute for Biological Studies in La Jolla, Calif., and colleagues used high-density oligonucleotide arrays to look at single nucleotide polymorphisms of 20 diverse strains of the plant.1 The group found that, since 2000, abo
Group migration
The Scientist Staff | Sep 30, 2007
While the internal mechanisms that guide cell migration have been described for individual cells, Pernille Rørth at the European Molecular Biology Laboratory in Heidelberg, Germany, and colleagues examined signaling activation in Drosophila border cells to uncover how groups of cells migrate collectively. They found that in the later phase of migration, leading cells have more mitogen-activated protein (MAP) kinase activation than trailing cells.1 "What's setting direction
Papers to Watch
The Scientist Staff | Aug 31, 2007
S. Ge et al.,"A critical period for enhanced synaptic plasticity in newly generated neurons of the adult brain," Neuron, 54:559-66, May 24, 2007. "By following GFP-labeled newly-born adult dentate granule cells, a critical period of 1-1.5 months was identified, and the increased plasticity depended on developmentally regulated synaptic expression of NR2B-containing NMDA [N-methyl d-aspartate] receptors. This critical period may be important for mediating e
Lifespan Controls Fail
The Scientist Staff | Aug 31, 2007
Credit: Courtesy of wikimedia" /> Credit: Courtesy of wikimedia Scientists had previously found that mutations in the Indy (I'm not dead yet) gene in male Drosophila from a particular genetic background result in flies with doubled lifespan. Linda Partridge at University College London and her colleagues aimed to use Indy mutant flies as positive controls for studies on how single genes affect longevity, but instead, they found that the mutants didn't live as long as previous work ha
Transvascular siRNA Delivery
The Scientist Staff | Aug 31, 2007
The tight network of endothelial cells of brain capillaries have, until now, kept therapeutic molecules, such as small interfering RNAs (siRNAs), from crossing from the blood into the brain. Such molecules could potentially silence targeted genes expressed in neurologic disorders. N. Manjunath Swamy from Harvard University Medical School and colleagues synthesized a peptide derived from rabies virus glycoprotein (RVG) and showed that the 29-amino-acid peptide bound specifically to acety
HIV: from chimps to humans
The Scientist Staff | Jul 31, 2007
HIV-1 strains in humans arose from three independent ape-to-human transmissions in the early 20th century, but the viral adaptation in humans remained unknown until now. Paul Sharp and colleagues from the University of Nottingham Queens Medical Centre in England compared full-length genome sequences of chimpanzee HIV strains with inferred ancestral sequences for three different phylogenetic HIV-1 groups in humans: M, N and O. They found that cross-species transmission in all three gr