Bio-Med Roundup

This month in Bio-Med Roundup:
  • Chen et al. discovered that a small molecule that activates the mitochondrial enzyme aldehyde dehydrogenase-2 reduces the extent of heart damage in a rodent model of heart attack.
  • Hong et al. and Prabhakar et al. offered insight into the evolution of regulatory sequences that control gene expression.
  • Toyama et al. showed that programmed cell death contributes to the mechanical forces that drive cell movements and cell shape changes during fruit fly embryogenesis.
  • Pastalkova et al. provided evidence that neuron firing patterns in the hippocampus are involved in recalling past experiences.
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MEDICINE
 
A Neoplastic Gene Fusion Mimics Trans-Splicing of RNAs in Normal Human Cells (5 September 2008)
H. Li, J. Wang, G. Mor, J. Sklar
A chimeric messenger RNA generated in a tumor by a DNA rearrangement is also, unexpectedly, expressed in healthy cells, a result of splicing together two separate messenger RNAs.
See related Perspective.

Germline Allele-Specific Expression of TGFBR1 Confers an Increased Risk of Colorectal Cancer (5 September 2008)
L. Valle et al.
In patients with colorectal cancer, one allele of the transforming growth factor ?gene produces less messenger RNA and thus less protein, a likely contributor to disease risk.

Activation of Aldehyde Dehydrogenase-2 Reduces Ischemic Damage to the Heart (12 September 2008)
C.-H. Chen et al.
A compound that activates the mitochondrial enzyme aldehyde dehydrogenase-2 reduces the extent of heart damage in a rodent model of heart attack.

Clusters of Hyperactive Neurons Near Amyloid Plaques in a Mouse Model of Alzheimer’s Disease (19 September 2008)
M. A. Busche et al.
In a mouse model of Alzheimer’s disease, neurons close to the characteristic deposits of amyloid show high activity, in contrast to the overall reduction in brain function.

Core Signaling Pathways in Human Pancreatic Cancers Revealed by Global Genomic Analyses (26 September 2008)
S. Jones et al.
Sequencing of DNA mutations shows that the same 12 signaling pathways are disrupted in most pancreatic tumors, suggesting these as key to tumor development.

An Integrated Genomic Analysis of Human Glioblastoma Multiforme (26 September 2008)
D. W. Parsons et al.
Comprehensive analysis of mutations in a brain cancer identifies previously unidentified cancer genes and a frequently mutated protein that may serve as a therapeutic marker.

Disruption of the CFTR Gene Produces a Model of Cystic Fibrosis in Newborn Pigs (26 September 2008)
C. S. Rogers et al.
Newborn pigs carrying a mutated copy of the gene defective in cystic fibrosis exhibit many features of the human disease and may provide fresh insights for therapy.

Seeding and Propagation of Untransformed Mouse Mammary Cells in the Lung (26 September 2008)
K. Podsypanina et al.
In mice, normal mammary cells can colonize the lung, suggesting that metastases might arise from displaced normal cells acquiring genetic changes that confer malignancy.
See related Perspective.


NEUROSCIENCE/PSYCHOLOGY

Internally Generated Cell Assembly Sequences in the Rat Hippocampus (5 September 2008)
E. Pastalkova, V. Itskov, A. Amarasingham, G. Buzsáki
As rats perform a memory task, cells in their hippocampus fire in self-generated sequences that correspond to and presage the animals’ subsequent choices.

Unsupervised Natural Experience Rapidly Alters Invariant Object Representation in Visual Cortex (12 September 2008)
N. Li and J. J. DiCarlo
Neurons in the most complex area of the brain’s visual cortex can respond to a particular object in any orientation by rapidly learning to associate multiple views of that object.

Political Attitudes Vary with Physiological Traits (19 September 2008)
D. R. Oxley et al.
Individuals’ views on political issues relate to their physiological reactions to threatening stimuli: Desire to protect their group’s interests correlates with greater reactivity to threat.

Reward-Predictive Cues Enhance Excitatory Synaptic Strength onto Midbrain Dopamine Neurons (19 September 2008)
G. D. Stuber et al.
When a rat learns to associate a cue with a reward, dopaminecontaining neurons in the midbrain acquire an enhanced response to that cue through the action of glutamate.

Infants’ Perseverative Search Errors Are Induced by Pragmatic Misinterpretation (26 September 2008)
J. Topál, G. Gergely, Á. Miklósi, Á. Erdo’’hegyi, G. Csibra
Infants may make mistakes in certain tasks because of the powerful effects of social interaction with an adult, not because of brain immaturity as was previously assumed.

The Coevolution of Cultural Groups and Ingroup Favoritism (26 September 2008)
C. Efferson, R. Lalive, E. Fehr
Results of a laboratory game show that cultural groups and ingroup favoritism arise spontaneously when individuals display an external marker that predicts their actions.

Understanding Overbidding: Using the Neural Circuitry of Reward to Design Economic Auctions (26 September 2008)
M. R. Delgado, A. Schotter, E. Y. Ozbay, E. A. Phelps
Brain areas sensitive to loss are selectively engaged during bidding in an auction, suggesting that the desire to avoid loss underlies the phenomenon of overbidding.
See related Perspective.


CELL/DEVELOPMENTAL BIOLOGY

Shadow Enhancers as a Source of Evolutionary Novelty (5 September 2008)
J.-W. Hong, D. A. Hendrix, M. S. Levine
Some developmentally important genes can be regulated via two enhancers, one located nearby and the other, a "shadow" enhancer, 10 to 20 kilobases away.
See related Perspective.

Wnt3a-Mediated Formation of Phosphatidylinositol 4,5-Bisphosphate Regulates LRP6 Phosphorylation (5 September 2008)
W. Pan et al.
The interaction of the signaling molecule Wnt to its receptor triggers accumulation of a lipid regulator, which stimulates phosphorylation of the receptor and cellular responses.

Dual Origin of Tissue-Specific Progenitor Cells in Drosophila Tracheal Remodeling (12 September 2008)
M. Weaver and M. A. Krasnow
When fruit flies metamorphose from larvae, a new trachea forms both from undifferentiated cells of the imaginal disc and differentiated cells that re-enter the cell cycle.
See related Perspective.

FBXW7 Targets mTOR for Degradation and Cooperates with PTEN in Tumor Suppression (12 September 2008)
J.-H. Mao et al.
A tumor suppressor is shown to control the degradation of a central protein regulator of cell proliferation.

Conformational Switch of Syntaxin-1 Controls Synaptic Vesicle Fusion (12 September 2008)
S. H. Gerber et al.
The synaptic vesicle protein that mediates membrane fusion during exocytosis also regulates the rate and extent of this process by controlling vesicle tethering.

Apoptotic Force and Tissue Dynamics During Drosophila Embryogenesis (19 September 2008)
Y. Toyama, X. G. Peralta, A. R. Wells, D. P. Kiehart, G. S. Edwards
During development, programmed cellular death within sheets of cells can generate forces that accelerate tissue fusion; a similar process may apply to wound healing.
See related Perspective.


GENETICS

Human-Specific Gain of Function in a Developmental Enhancer (5 September 2008)
S. Prabhakar et al.
When transferred to a mouse, a conserved regulatory element that has been positively selected in humans is robustly expressed at the base of its developing thumb and wrist.
See related Perspective.

A Mutation in Hairless Dogs Implicates FOXI3 in Ectodermal Development (12 September 2008)
C. Drögemüller et al.
Mutations in a transcription factor gene involved in ectodermal development cause a lack of hair and abnormal teeth in Chinese Crested, Mexican, and Peruvian hairless dogs.


BIOCHEMISTRY
 
The Crystal Structure of a Mammalian Fatty Acid Synthase (5 September 2008)
T. Maier, M. Leibundgut, N. Ban
A high-resolution structure of mammalian fatty acid synthase reveals that this enzyme is derived from an iterative polyketide synthase and has five active catalytic domains.
See related Perspective.

Helical Structures of ESCRT-III Are Disassembled by VPS4 (5 September 2008)
S. Lata et al.
A protein responsible for the final separation of daughter cells or budding viruses forms heteromeric complexes on the inside of the membrane to regulate the abscission step.

Antigen Recognition by Variable Lymphocyte Receptors (26 September 2008)
B. W. Han, B. R. Herrin, M. D. Cooper, I. A. Wilson
The receptor that binds antigens in jawless vertebrates differs from the immunoglobulins of jawed vertebrates and uses a variable concave surface and carboxyl terminal for recognition.


MOLECULAR BIOLOGY

Degradation of microRNAs by a Family of Exoribonucleases in Arabidopsis (12 September 2008)
V. Ramachandran and X. Chen
A class of nucleases specific for short single-stranded RNAs is found to degrade microRNAs in Arabidopsis; their mutation results in numerous developmental defects.

Molecular Coupling of Xist Regulation and Pluripotency (19 September 2008)
P. Navarro et al.
X chromosome inactivation in stem cells is reversed, a step in allowing them to become pluripotent, when three factors repress the inactivation RNA.


MICROBIOLOGY

An Alternative Menaquinone Biosynthetic Pathway Operating in Microorganisms (19 September 2008)
T. Hiratsuka et al.
Some pathogens synthesize the essential vitamin menaquinone by an unusual pathway, presenting a potential target for new antibiotics.
See related Perspective.

An Inhibitor of FtsZ with Potent and Selective Anti-Staphylococcal Activity (19 September 2008)
D. J. Haydon et al.
A small synthetic molecule directed against a microbial protein required for cell division protects mice infected with Staphylococcus aureus from death.
See related Perspective.


IMMUNOLOGY

Apobec3 Encodes Rfv3, a Gene Influencing Neutralizing Antibody Control of Retrovirus Infection (5 September 2008)
M. L. Santiago et al.
A resistance factor known to protect mice from retroviral infection is unexpectedly identified as Apobec3, a deoxycytidine deaminase that controls somatic hypermutation.


PLANT SCIENCE

Suppression of Cotton Bollworm in Multiple Crops in China in Areas with Bt Toxin-Containing Cotton (19 September 2008)
K.-M. Wu, Y.-H. Lu, H.-Q. Feng, Y.-Y. Jiang, J.-Z. Zhao
Planting engineered cotton that expresses a natural toxin reduces pest damage to both the cotton itself and to other crops planted nearby, reducing the need for insecticidal spray.


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