This month in Bio-Med Roundup:
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Regulated Pole-to-Pole Oscillations of a Bacterial Gliding Motility Protein
T. Mignot, J. P. Merlie Jr., D. R. Zusman
Certain bacteria change their course by a protein that oscillates from one end to the other, directing the assembly of a pilus.
Logic of the Yeast Metabolic Cycle:Temporal Compartmentalization of Cellular Processes (
B. P. Tu, A. Kudlicki, M. Rowicka, S. L. McKnight
Two protein components of the transcriptional feedback loops that form the circadian clock move into the nucleus independently, invalidating a central assumption about the clock’s timekeeping mechanism.
Regulation of Yeast Replicative Life Span by TOR and Sch9 in Response to Nutrients
M. Kaeberlein, R. W. Powers III, K. K. Steffen, E. A.Westman, D. Hu, N. Dang, E. O. Kerr, K. T. Kirkland, S. Fields, B. K. Kennedy
A search of all yeast genes identifies two signaling enzymes belonging to a pathway that increases life span when calories are restricted.
See related Perspective at http://www.sciencemag.org/cgi/content/summary/310/5751/1124
Golgi Duplication in Trypanosoma brucei Requires Centrin2
C. Y. He, M. Pypaert, G. Warren
A bi-lobed structure within cells contains an organelle-replication protein, which is required for duplication and faithful segregation of the Golgi complex to daughter cells.
Wingless Signaling at Synapses Is Through Cleavage and Nuclear Import of Receptor DFrizzled2
D. Mathew, B. Ataman, J. Chen, Y. Zhang,
A cell surface receptor at the neuromuscular junction is unexpectedly cleaved when bound by ligand, releasing a fragment that travels to the nucleus to control synapse formation.
See related Perspective at http://www.sciencemag.org/cgi/content/summary/310/5752/1284
Tissue-Specific TAFs Counteract Polycomb to Turn on Terminal Differentiation
X. Chen, M. Hiller, Y. Sancak, M. T. Fuller
Transcription factors found only in the testes direct germ cell precursors to become mature sperm by displacing repressive proteins on the promoters of differentiation genes.
SMEDWI-2 Is a PIWI-like Protein That Regulates Planarian Stem Cells
P. W. Reddien, N. J. Oviedo, J. R. Jennings, J. C. Jenkin, A. Sánchez Alvarado
Certain flatworms are able to regenerate damaged body parts because a protein possibly involved in RNA regulation of gene expression allows stem cells to produce new tissue.
LIN-12/Notch Activation Leads to MicroRNA-Mediated Down-Regulation of Vav in C. elegans
A. S. Yoo and
A microRNA participates in the cell-cell interactions and biochemical feedback that specify the identity of vulva cells in a developing nematode.
See related Perspective at http://www.sciencemag.org/cgi/content/summary/310/5752/1288
Ancient DNA from the First European Farmers in 7500-Year-Old Neolithic Sites
W. Haak, P. Forster, B. Bramanti, S. Matsumura, G. Brandt, M.Tänzer, R.Villems, C. Renfrew, D. Gronenborn, K. W. Alt, J. Burger
Modern Europeans are mainly descended from Paleolithic hunter-gatherers rather than Neolithic farmers, and probably acquired agriculture through cultural transmission.
The Pseudo-Response Regulator Ppd-H1 Provides Adaptation to Photoperiod in Barley
A. Turner, J. Beales, S. Faure, R. P. Dunford, D. A. Laurie
The delayed flowering of spring-sown barley, which allows larger grain yields, is caused by a gene mutation that reduces the sensitivity of the flowering pathway to longer days.
GTF2IRD1 in Craniofacial Development of Humans and Mice
M. Tassabehji, P. Hammond, A. Karmiloff-Smith, P. Thompson, S. S. Thorgeirsson, M. E. Durkin, N. C. Popescu, T. Hutton, K.Metcalfe, A. Rucka et al.
Of the 28 genes deleted in the complex human disorder Williams-Beuren syndrome, one has been identified as responsible for the facial abnormalities seen in patients.
DISC1 and PDE4B Are Interacting Genetic Factors in Schizophrenia That Regulate
J. K. Millar, B. S. Pickard, S. Mackie, R. James, S. Christie, S. R. Buchanan, M. P. Malloy, J. E. Chubb, E. Huston, G. S. Baillie et al.
Two genes associated with schizophrenia code for interacting proteins that modulate cyclic AMP metabolism, suggesting that this signaling pathway may contribute to the disorder.
See related Perspective at http://www.sciencemag.org/cgi/content/summary/310/5751/1128
Vertebrate-Type Intron-Rich Genes in the Marine Annelid Platynereis dumerilii
F. Raible, K. Tessmar-Raible, K. Osoegawa, P. Wincker, C. Jubin, G. Balavoine, D. Ferrier, V. Benes, P. de Jong, J. Weissenbach et al.
Genes resembling intron-rich human genes are found in a marine polychaete, indicating their presence in the bilateral ancestor and their secondary loss in other invertebrates.
Obestatin, a Peptide Encoded by the Ghrelin Gene, Opposes Ghrelin’s Effects on Food Intake
J. V. Zhang, P.-G. Ren, O. Avsian-Kretchmer, C.-W. Luo, R. Rauch, C. Klein, A. J. W. Hsueh
The gene for a hormone that stimulates feeding in rats also codes for another, opposing hormone that suppresses food intake and decreases body weight gain.
See related Perspective at http://www.sciencemag.org/cgi/content/summary/310/5750/985
Small-Molecule Inhibition of TNF-a
M. M. He, A. S. Smith, J. D. Oslob, W. M. Flanagan, A. C. Braisted, A. Whitty, M. T. Cancilla, J. Wang, A. A. Lugovskoy, J. C. Yoburn et al.
A potentially useful small-molecule inhibitor interferes with the action of a trimeric inflammatory hormone by displacing a subunit and binding to the resulting dimer.
Structures of the Bacterial Ribosome at 3.5 Å Resolution
B. S. Schuwirth, M. A. Borovinskaya, C. W. Hau, W. Zhang, A. Vila-Sanjurjo, J. M. Holton, J. H. D. Cate
Structures of two forms of the E. coli ribosome reveal new atomic details and suggest how various parts of the molecule move during protein synthesis.
See related Perspective at http://www.sciencemag.org/cgi/content/summary/310/5749/793
A Thiolate-Ligated Nonheme Oxoiron(IV) Complex Relevant to Cytochrome P450
M. R. Bukowski, K. D. Koehntop, A. Stubna, E. L. Bominaar, J. A. Halfen, E. Münck, W. Nam, L. Que Jr.
A rigid ligand framework enables realization of an elusive active-site model for cytochrome P450 enzymes, with sulfur coordinated stably to iron in an oxidizing environment.
Photosynthetic O2 Formation Tracked by Time-Resolved X-ray Experiments
M. Haumann, P. Liebisch, C. Müller, M. Barra, M. Grabolle, H. Dau
X-ray spectroscopy with a resolution of 10 microseconds reveals an elusive oxygen intermediate in the final step of photosynthesis.
See related Perspective at http://www.sciencemag.org/cgi/content/summary/310/5750/982
Structure of a V3-Containing HIV-1 gp120 Core
C. Huang, M. Tang, M.-Y. Zhang, S. Majeed, E. Montabana, R. L. Stanfield, D. S. Dimitrov, B. Korber, J. Sodroski, I. A.Wilson et al.
An exposed ~50 Å “hook” on HIV-1 helps it bind to host cells and provides a specific target for most natural antibodies to HIV.
Structure of the Quaternary Complex of Interleukin-2 with Its a, b, and gc Receptors
X.Wang, M. Rickert, K. C. Garcia
A hormone activates immune cells by sequentially recruiting two specific receptors and then a common third receptor, forming a high-affinity signaling complex.
A Direct Role for Dual Oxidase in Drosophila Gut Immunity
E.-M. Ha, C.-T. Oh, Y. S. Bae, W.-J. Lee
Reactive oxygen species in the lining of the Drosophila gut protect against microbial infection, just as they do in other cells of the innate immune system in many organisms.
Treatment of Autoimmune Neuroinflammation with a Synthetic Tryptophan Metabolite
M. Platten, P. P. Ho, S. Youssef, P. Fontoura, H. Garren, E. M. Hur, R. Gupta, L. Y. Lee, B. A. Kidd, W. H. Robinson et al.
Breakdown products of the amino acid tryptophan inhibit immune responses and improve symptoms in an experimental form of multiple sclerosis in mice.
Altered TCR Signaling from Geometrically Repatterned Immunological Synapses
K. D. Mossman, G. Campi, J. T. Groves, M. L. Dustin
Manipulating the position of the antigen receptor within the immune synapse shows that receptors near the outside work best.
Assistance of Microbial Glycolipid Antigen Processing by CD1e
H. de la Salle, S. Mariotti, C. Angenieux, M. Gilleron, L.-F. Garcia-Alles, D. Malm, T. Berg, S. Paoletti, B. Maître, L. Mourey et al.
One member of an immune protein family helps to process lipid antigens for display on the cell surface; the other members provide the surface binding sites for these lipids.
Retrograde Signaling by Syt 4 Induces Presynaptic Release and Synapse-Specific Growth
M. Yoshihara, B. Adolfsen, K. T. Galle, J. T. Littleton
Information can travel “backward” across a synapse by calcium-triggered vesicle fusion and release of signals
that stimulate presynaptic activity and growth.
Fast Readout of Object Identity from Macaque Inferior Temporal Cortex
C. P. Hung, G. Kreiman, T. Poggio, J. J. DiCarlo
Activity in as few as 100 cortical brain cells for 12.5 milliseconds is enough for a monkey to recognize the identity and general category of an object.
Neuronal Activity Regulates Diffusion Across the Neck of Dendritic Spines
B. L. Bloodgood and B. L. Sabatini
Neuronal activity regulates the diffusion of molecules between neuronal processes and their synapse-supporting spines, suggesting a new form of synaptic regulation.
Representation of Action-Specific Reward Values in the Striatum
K. Samejima, Y. Ueda, K. Doya, M. Kimura
Monkeys assign a subjective reward value to their choices when making decisions, and this value is coded by neurons in an area near the center of the brain.
Nucleus Accumbens Long-Term Depression and the Expression of Behavioral Sensitization
K. Brebner, T. P. Wong, L. Liu, Y. Liu, P. Campsall, S. Gray, L. Phelps, A. G. Phillips, Y. T. Wang
A type of neuronal plasticity in the rat that may underlie persistent drug craving in humans depends on the uptake and sequestration of glutamate receptors.