Bio-Med Roundup

This month in Bio-Med Roundup:
  • Hagedorn et al. showed that tubercular mycobacteria can slip undetected from host cell to host cell via specialized exit structures called ejectosomes.
  • Bostrom et al. found that the antigen binding site of a therapeutic antibody for cancer simultaneously binds two proteins required for tumor growth.
  • Han et al. showed that fear memory in mice can be erased by selective killing of a subpopulation of lateral amygdala neurons.
  • Fu et al. and Krattinger et al. offered insight into the molecular mechanisms that confer fungal disease resistance in wheat.
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Sponsored by:
$25,000 Prize for Neurobiology
Now accepting entries for the $25,000
Eppendorf & Science Prize for Neurobiology
Deadline: June 15, 2009
Visit www.eppendorf.com/prize2009



CELL BIOLOGY
 
Sensing Chromosome Bi-Orientation by Spatial Separation of Aurora B Kinase from Kinetochore Substrates (6 March 2009)
D. Liu, G. Vader, M. J. M. Vromans, M. A. Lampson, S. M. A. Lens
The mechanism for sensing tension across chromosome pairs before mitotic separation relies on the distance between enzyme and substrate.

A Recessive Mutation in the APP Gene with Dominant-Negative Effect on Amyloidogenesis (13 March 2009)
G. Di Fede et al.
A mutation in the amyloid precursor protein gene causes Alzheimer’s disease in homozygotic patients.

Structure of the Anaphase-Promoting Complex/Cyclosome Interacting with a Mitotic Checkpoint Complex (13 March 2009)
F. Herzog et al.
Electron microscopy captures cell cycle checkpoint proteins in the act of inhibiting cell division in HeLa cells. 

Ankyrin-G Promotes Cyclic Nucleotide–Gated Channel Transport to Rod Photoreceptor Sensory Cilia (20 March 2009)
K. Kizhatil, S. A. Baker, V. Y. Arshavsky, V. Bennett
The assembly and function of key photoreceptor proteins in neonatal mouse retinas is mediated by the protein ankyrin-G.

Comprehensive Characterization of Genes Required for Protein Folding in the Endoplasmic Reticulum (27 March 2009)
M. C. Jonikas et al.
A nine-protein transmembrane is among several hundred genes found to be critical for protein folding in the endoplasmic reticulum.

Changes in Temperature Preferences and Energy Homeostasis in Dystroglycan Mutants (27 March 2009)
K. Takeuchi et al.
Mutation of a membrane protein alters mitochondrial metabolism and temperature preference in flies.

Quantitative 3D Video Microscopy of HIV Transfer Across T Cell Virological Synapses (27 March 2009)
W. Hübner et al.
HIV uses the endocytic pathway to spread through virological synapses between immune cells.


NEUROSCIENCE/PSYCHOLOGY

Functional Proteomics Identify Cornichon Proteins as Auxiliary Subunits of AMPA Receptors (6 March 2009)
J. Schwenk et al.
A distinctive family of proteins involved in the assembly of the most common excitatory brain receptor has been discovered.
See related Perspective

The Dynamic Control of Kiss-And-Run and Vesicular Reuse Probed with Single Nanoparticles (13 March 2009)
Q. Zhang, Y. Li, R. W. Tsien
A transient form of vesicle fusion that allows vesicle reuse is more prevalent early during synaptic response to a train of stimuli.

Selective Erasure of a Fear Memory (13 March 2009)
J.-H. Han et al.
Fear memory in mice is erased by experimental killing of a subpopulation of lateral amygdala neurons.

Human Substantia Nigra Neurons Encode Unexpected Financial Rewards (13 March 2009)
K. A. Zaghloul et al.
Dopamine neurons in the human mid-brain are activated by unexpected rewards and differentiate positive and negative feedback.

RSY-1 Is a Local Inhibitor of Presynaptic Assembly in C. elegans (13 March 2009)
M. R. Patel and K. Shen
The protein RSY-1 inhibits synapse formation by antagonizing assembly molecules during presynaptic development.

The Surprising Power of Neighborly Advice (20 March 2009)
D. T. Gilbert, M. A. Killingsworth, R. N. Eyre, T. D. Wilson
A stranger’s reaction to a social situation is a more accurate guide to our own reaction than is a written description of the situation.

Genetic Contribution to Variation in Cognitive Function: An fMRI Study in Twins (27 March 2009)
J. W. Koten Jr. et al.
Analysis of identical and fraternal twins shows genetic influence on brain activation during arithmetic and memory tasks.



MICROBIOLOGY

Geometric Cue for Protein Localization in a Bacterium (6 March 2009)
K. S. Ramamurthi, S. Lecuyer, H. A. Stone, R. Losick
Membrane curvature controls the localization of a small peripheral membrane protein during bacterial spore formation.  

Flagellum Mediates Symbiosis (20 March 2009)
T. Shimoyama, S. Kato, S. Ishii, K. Watanabe
A bacterium uses its flagellum to grip its archaeal symbiotic partner and to stimulate hydrogen consumption.

Infection by Tubercular Mycobacteria Is Spread by Nonlytic Ejection from Their Amoeba Hosts (27 March 2009)
M. Hagedorn, K. H. Rohde, D. G. Russell, T. Soldati
Tubercular bacteria can slip undetected from host cell to host cell via specialized exit structures called ejectosomes.
See related Perspective.



MOLECULAR BIOLOGY

Extremely High Mutation Rate of a Hammerhead Viroid (6 March 2009)
S. Gago, S. F. Elena, R. Flores, R. Sanjuán
Viroids, the smallest RNA replicators in plants, have the highest error rates yet recorded.

A Role for RNAi in the Selective Correction of DNA Methylation Defects (20 March 2009)
F. K. Teixeira et al.
An RNA interference–dependent DNA methylation rescue system helps to preserve a subset of DNA methylation marks in Arabidopsis.
See related Perspective.



IMMUNOLOGY

Preferential Generation of Follicular B Helper T Cells from Foxp3+ T Cells in Gut Peyer’s Patches (13 March 2009)
M. Tsuji et al.
Suppressor T cells selectively differentiate into helper T cells in the mouse gut and thereby promote immune homeostasis.

Variants of the Antibody Herceptin That Interact with HER2 and VEGF at the Antigen Binding Site (20 March 2009)
J. Bostrom et al.
The antigen binding site of a therapeutic antibody for cancer simultaneously binds two proteins required for tumor growth.
See related Perspective.

CD24 and Siglec-10 Selectively Repress Tissue Damage–Induced Immune Responses (27 March 2009)
G.-Y. Chen, J. Tang, P. Zheng, Y. Liu
A signaling pathway involving an immune protein protects cells against the potentially fatal immune response induced by tissue damage.
See related Perspective.

Visualizing Antigen-Specific and Infected Cells in Situ Predicts Outcomes in Early Viral Infection (27 March 2009)
Q. Li et al.
Mapping the rate and magnitude of early events in viral infections predicts the success or failure of immune control.



MEDICINE
 
Spinal Cord Stimulation Restores Locomotion in Animal Models of Parkinson’s Disease (20 March 2009)
R. Fuentes, P. Petersson, W. B. Siesser, Ma. G. Caron, M. A. L. Nicolelis
Epidural stimulation of spinal neural pathways produces specific shifts in activity in neural circuits affecting movement.

A Transposon-Based Genetic Screen in Mice Identifies Genes Altered in Colorectal Cancer (27 March 2009)
T. K. Starr et al.
A functional screen in mice uncovers genes that are likely to drive the growth of gut-specific tumors. 



BIOCHEMISTRY/BIOPHYSICS

The Role of Fingerprints in the Coding of Tactile Information Probed with a Biomimetic Sensor (13 March 2009)
J. Scheibert, S. Leurent, A. Prevost, G. Debrégeas
Fingertip ridges improve the tactile perception of fine features.

Structure of P-Glycoprotein Reveals a Molecular Basis for Poly-Specific Drug Binding (27 March 2009)
S. G. Aller et al.
A membrane protein that removes toxins and drugs from cells is caught binding two drug molecules in a large internal cavity.
See related Perspective.



PLANT SCIENCE

A Kinase-START Gene Confers Temperature-Dependent Resistance to Wheat Stripe Rust (6 March 2009)
D. Fu et al.  
A Putative ABC Transporter Confers Durable Resistance to Multiple Fungal Pathogens in Wheat (6 March 2009)
S. G. Krattinger et al.  
Several specific genes in wheat confer resistance to common fungal diseases.
See related Perspective.

A Functional Genomics Approach Reveals CHE as a Component of the Arabidopsis Circadian Clock (13 March 2009)
J. L. Pruneda-Paz, G. Breton, A. Para, S. A. Kay
A transcription factor (CHE) binds the promoter of the clock gene CCA1, adding to the molecular clock circuitry in plants.
See related Perspective.

Paternal Control of Embryonic Patterning in Arabidopsis thaliana (13 March 2009)
M. Bayer et al.
Transcripts of a cytoplasmic gene from sperm are translated after fertilization and control asymmetric zygotic division.
See related Perspective.

The Domestication Process and Domestication Rate in Rice: Spikelet Bases from the Lower Yangtze (20 March 2009)
D. Q. Fuller et al.
Remains of domestic and wild rice trace the process of rice domestication in China to between 6900 and 6600 years ago.





Sponsored by:
$25,000 Prize for Neurobiology
Now accepting entries for the $25,000
Eppendorf & Science Prize for Neurobiology
Deadline: June 15, 2009
Visit www.eppendorf.com/prize2009