Bio-Med Roundup

This month in Bio-Med Roundup:
  • Tang et al. provided new insight into the origin of fat cells.
  • Wilson et al. showed that differences in regulatory DNA sequences can drive species-specific gene expression.
  • Bacaj et al. found that glial cells are required for the normal function of the main sensory organ in the nematode C. elegans.
  • Paux et al. presented a physical map of the largest chromosome of bread wheat.
Jump to:





CELL/DEVELOPMENTAL BIOLOGY
 
Chemokine Signaling Controls Endodermal Migration During Zebrafish Gastrulation (3 October 2008)
S. Nair and T. F. Schilling
During zebrafish gastrulation, chemokines are required for integrin-dependent adhesion of endodermal cells to mesoderm, a role distinct from their action as chemoattractants.

High-Quality Binary Protein Interaction Map of the Yeast Interactome Network (3 October 2008)
H. Yu et al.
Comparison of existing methods for mapping protein-protein interactions in yeast cells shows that the high-throughput approaches are complementary to one another.
See related Perspective.

Ceramide Biogenesis Is Required for Radiation-Induced Apoptosis in the Germ Line of C. elegans (3 October 2008)
X. Deng et al.
In worms, lipid signaling at the mitochondria is necessary for the germ cell death that follows radiation damage, but not for normal developmental cell death.

Phosphorylation Networks Regulating JNK Activity in Diverse Genetic Backgrounds (17 October 2008)
C. Bakal et al.
Data from an RNA interference screen, combined with genetic interaction analysis, allow construction of a comprehensive kinase cellular signaling network in Drosophila.

Higher-Order Cellular Information Processing with Synthetic RNA Devices (17 October 2008)
M. N. Win and C. D. Smolke
The intrinsic ribozyme of a simple RNA-based Boolean logic device that can be engineered into cells is activated when it is bound by two particular molecules.
See related Perspective.

White Fat Progenitor Cells Reside in the Adipose Vasculature (24 October 2008)
W. Tang et al.
Adipocytes (fat cells) originate from precursor cells that reside within the walls of the blood vessels that feed fat tissue.
See related Perspective.

TMEM16A, A Membrane Protein Associated with Calcium-Dependent Chloride Channel Activity (24 October 2008)
A. Caputo et al.
A transmembrane protein induced in cytokine-treated bronchial epithelial cells seems to be a long-sought primary carrier of a voltage- and calcium-dependent chloride current.
See related Perspective.

Aneuploidy Affects Proliferation and Spontaneous Immortalization in Mammalian Cells (31 October 2008)
B. R. Williams et al.
Mouse cell lines carrying extra copies of one of four chromosomes all show less cell proliferation and higher gene expression, but vary in how fast they become cancer-like cells.
See related Perspective.


BIOCHEMISTRY

Molecular Architecture of the "Stressosome," a Signal Integration and Transduction Hub (3 October 2008)
J. Marles-Wright et al.
The stressosome, a huge multiprotein complex, has a virus capsid–like core and variable extensions that detect and integrate signals to activate the stress response.

Small Molecule–Induced Allosteric Activation of the Vibrio cholerae RTX Cysteine Protease Domain (10 October 2008)
P. J. Lupardus, A. Shen, M. Bogyo, K. C. Garcia
Cholera toxin becomes active inside an infected cell when a host lipid binds to it, allosterically exposing its active site, which allows autoproteolysis and thus infection.

Surface Sites for Engineering Allosteric Control in Proteins (17 October 2008)
J. Lee et al.
Two allosterically regulated proteins can be engineered to interact so that when light activates one, it triggers the enzymatic output (dihydrofolate reductase) of the other.

A Stochastic Single-Molecule Event Triggers Phenotype Switching of a Bacterial Cell (17 October 2008)
P. J. Choi, L. Cai, K. Frieda, X. S. Xie
A stochastic process, in which a regulatory repressor dissociates from either one or two DNA sites, determines which of two phenotypes is seen in genetically identical bacteria.

Remeasuring the Double Helix (17 October 2008)
R. S. Mathew-Fenn, R. Das, P. A. B. Harbury
Pieces of DNA in solution are much softer than DNA under tension and unexpectedly stretch large amounts over several helical turns.

The Structure of a Transcribing T7 RNA Polymerase in Transition from Initiation to Elongation (24 October 2008)
K. J. Durniak, S. Bailey, T. A. Steitz
In order to accommodate the elongating RNA transcript, a viral RNA polymerase rotates on its DNA binding promoter to expand the active site.

Midbody Targeting of the ESCRT Machinery by a Noncanonical Coiled Coil in CEP55 (24 October 2008)
H. H. Lee, N. Elia, R. Ghirlando, J. Lippincott-Schwartz, J. H. Hurley
As daughter cells separate, final cleavage of the membranes requires a protein with a coiled coil built around an unusual charged core, which recruits other constituents.

Structure and Molecular Mechanism of a Nucleobase–Cation–Symport-1 Family Transporter (31 October 2008)
S. Weyand et al.
The structure of a membrane transporter in an open state suggests that in- and out-facing cavities reciprocally open and close coordinated by two transmembrane segments.


NEUROSCIENCE/PSYCHOLOGY

Internally Generated Reactivation of Single Neurons in Human Hippocampus During Free Recall (3 October 2008)
H. Gelbard-Sagiv, R. Mukamel, M. Harel, R. Malach, I. Fried
The firing patterns of brain neurons recorded from people watching a video episode were the same as those recorded during later recall of the same show.

Lacking Control Increases Illusory Pattern Perception (3 October 2008)
J. A. Whitson and A. D. Galinsky
When subjects receive false feedback in lab tests and so feel a loss of control, they are more apt to perceive patterns in random visual static and imagine conspiracies.

Relation Between Obesity and Blunted Striatal Response to Food Is Moderated by TaqIA A1 Allele (17 October 2008)
E. Stice, S. Spoor, C. Bohon, D. M. Small
Individuals whose reward centers of the brain respond sluggishly after eating prefer calorie-dense foods, which may account for their greater propensity to gain weight.

Experiencing Physical Warmth Promotes Interpersonal Warmth (24 October 2008)
L. E. Williams and J. A. Bargh
When people are given a warm rather than a cold drink, they are more likely to show generous behavior toward others.

Glia Are Essential for Sensory Organ Function in C. elegans (31 October 2008)
T. Bacaj, M. Tevlin, Y. Lu, S. Shaham
Nonneural glial cells are required for the normal operation of the main sensory organ of a nematode, influencing neuronal shape and function, as well as behavior.
See related Perspective.


GENETICS

Natural Selection on a Major Armor Gene in Threespine Stickleback (10 October 2008)
R. D. H. Barrett, S. M. Rogers, D. Schluter
In stickleback fish transferred to fresh water, selection against the allele for the costly armor plating only partly explains the changes in allele frequencies over generations.
See related Perspective.

Conservation and Rewiring of Functional Modules Revealed by an Epistasis Map in Fission Yeast (17 October 2008)
A. Roguev et al.
Comparison of genetic wiring in two types of yeast reveals that protein complexes are conserved, but the interactions between them can change radically between species.

Species-Specific Transcription in Mice Carrying Human Chromosome 21 (17 October 2008)
M. D. Wilson et al.
An aneuploid mouse carrying a human chromosome shows that genetic sequence can dominate epigenetic, cellular, and organismal effects in determining transcriptional regulation and gene expression.
See related Perspective.

Genetic Compatibility Affects Queen and Worker Caste Determination (24 October 2008)
T. Schwander and L. Keller
Although environmental signals regulate whether female ants become sterile workers or queens, genetic interactions between their parental genomes also influence the phenotype.

HARP Is an ATP-Driven Annealing Helicase (31 October 2008)
T. Yusufzai and J. T. Kadonaga
The gene deleted in a complex genetic disease is a reverse helicase, a motor-like enzyme that uses adenosine triphosphate to zip up separated strands of DNA.


IMMUNOLOGY
 
Noncytotoxic Lytic Granule-Mediated CD8+ T Cell Inhibition of HSV-1 Reactivation from Neuronal Latency (10 October 2008)
J. E. Knickelbein et al.
Herpes virus in neurons can be kept in a latent state by T cells, which release granzyme B, an inhibitor of a protein necessary for viral gene expression.

CTLA-4 Control over Foxp3+ Regulatory T Cell Function (10 October 2008)
K. Wing et al.
A protein in T regulatory cells controls their ability to dampen activation of the immune system by antigen-presenting cells,
preventing autoimmune disease.
See related Perspective.

Innate Immunity in Caenorhabditis elegans Is Regulated by Neurons Expressing NPR-1/GPCR (17 October 2008)
K. L. Styer et al.
In the worm Caenorhabditis elegans, sensory neurons surprisingly can inhibit innate immune responses, in part through the mitogen-activated protein kinase (MAPK) signaling pathway.

Deletion of Trpm7 Disrupts Embryonic Development and Thymopoiesis Without Altering Mg2+ Homeostasis (31 October 2008)
J. Jin et al.
A cation channel that conducts both Ca2+ and Mg2+ is unexpectedly required for normal mouse development, specifically for proper maturation of the thymus and T cells.


MOLECULAR BIOLOGY

Functional Targeting of DNA Damage to a Nuclear Pore–Associated SUMO-Dependent Ubiquitin Ligase (24 October 2008)
S. Nagai et al.
The damaged regions of DNA are recruited to the periphery of the nucleus by a complex of nuclear-pore and ubiquitin-modifying proteins, where they are repaired.

Splicing Factors Facilitate RNAi-Directed Silencing in Fission Yeast (24 October 2008)
E. H. Bayne et al.
In fission yeast, RNA splicing factors unexpectedly participate in the silencing of centromeric DNA by RNA interference derived from centromeres.

Polycomb Proteins Targeted by a Short Repeat RNA to the Mouse X Chromosome (31 October 2008)
J. Zhao, B. K. Sun, J. A. Erwin, J.-J. Song, J. T. Lee
A small RNA cleaved from a larger precursor recruits silencing proteins to the X chromosome to inactivate it in female mammals, which have an extra copy.


MICROBIOLOGY

Environmental Genomics Reveals a Single-Species Ecosystem Deep Within Earth (10 October 2008)
D. Chivian et al.
DNA sequences in water samples from a depth of 2.8 kilometers in a South African gold mine reveal the presence of a thermophilic microbe that can fix its own nitrogen and carbon.

Wolbachia and Virus Protection in Insects (31 October 2008)
L. M. Hedges, J. C. Brownlie, S. L. O’Neill, K. N. Johnson
An endosymbiotic bacterium survives and spreads in populations of Drosophila because it protects its insect hosts from death caused by certain RNA viruses.


PLANT SCIENCE

Rates of Molecular Evolution Are Linked to Life History in Flowering Plants (3 October 2008)
S. A. Smith and M. J. Donoghue
A phylogenetic analysis shows that long-lived trees and shrubs have lower rates of molecular evolution than short-lived herbaceous plants.

A Physical Map of the 1-Gigabase Bread Wheat Chromosome 3B (3 October 2008)
E. Paux et al.
A physical map of the largest chromosome of wheat provides the first step toward sequencing the huge, 17-billion base pair genome of this critical food crop.

Receptor-Like Kinase ACR4 Restricts Formative Cell Divisions in the Arabidopsis Root (24 October 2008)
I. De Smet et al.
A membrane kinase regulates the number of stem cells in the main tip of the root, as well as the de novo generation of stem cells in new laterally projecting roots.


MEDICINE

 H2S as a Physiologic Vasorelaxant: Hypertension in Mice with Deletion of Cystathionine γ-Lyase (24 October 2008)
G. Yang et al.
Hydrogen sulfide gas regulates blood pressure and blood vessel function in mice.