This month in Bio-Med Roundup:
- Tishkoff et al. presented a genetic history of African populations and African Americans.
- Ramsey et al. and Nakahata et al. described a transcriptional-enzymatic feedback loop that controls interactions between metabolism and circadian rhythms.
- Hare et al. used modeling and brain imaging to gain insight into the neural circuitry underlying choice and self-control.
- Tran et al. reported on a new drug candidate for the treatment of advanced prostate cancer.
CELL/DEVELOPMENTAL BIOLOGY
γ-Secretase Heterogeneity in the Aph1 Subunit: Relevance for Alzheimer’s Disease (1 May 2009)
L. Serneels et al.
Targeted knockout of only part of the γ-secretase complex lessens toxicity and still improves disease phenotypes.
See related Perspective.
Circadian Clock Feedback Cycle Through NAMPT-Mediated NAD+ Biosynthesis (1 May 2009)
K. M. Ramsey et al.
Circadian Control of the NAD+ Salvage Pathway by CLOCK-SIRT1 (1 May 2009)
Y. Nakahata et al.
A transcriptional-enzymatic feedback loop controls interactions between metabolism and circadian rhythms in mouse cells.
See related Perspective.
Apicomplexan Parasites Co-Opt Host Calpains to Facilitate Their Escape from Infected Cells (8 May 2009)
R. Chandramohanadas et al.
A host protease helps newly replicated microbial parasites escape from incubator cells.
Human Induced Pluripotent Stem Cells Free of Vector and Transgene Sequences (8 May 2009)
J. Yu et al.
Human induced pluripotent stem cells can be generated without integration of exogenous DNA into their genomes.
MAPK3/1 (ERK1/2) in Ovarian Granulosa Cells Are Essential for Female Fertility (15 May 2009)
H.-Y. Fan et al.
Targeted disruption of the kinases derails the molecular events that mediate induction of female reproductive development.
See related Perspective.
Cell Movements at Hensen’s Node Establish Left/Right Asymmetric Gene Expression in the Chick (15 May 2009)
J. Gros et al.
Asymmetric gene expression is passively set up in the early chick embryo by cell rearrangements.
A Role for the CHC22 Clathrin Heavy-Chain Isoform in Human Glucose Metabolism (29 May 2009)
S. Vassilopoulos et al.
A human-specific vesicle-forming protein regulates relocation of a glucose transporter to the cell membrane.
See related Perspective.
Proteasomal Regulation of the Hypoxic Response Modulates Aging in C. elegans (29 May 2009)
R. Mehta et al.
Induction of the hypoxic response in a worm slows aging and enhances resistance to proteotoxicity.
Synthetic Gene Networks That Count (29 May 2009)
A. E. Friedland et al.
Genetic counters with the ability to count up to three induction events are constructed in Escherichia coli.
See related Perspective.
MOLECULAR BIOLOGY
A Cytidine Deaminase Edits C to U in Transfer RNAs in Archaea (1 May 2009)
L. Randau et al.
A nonconventional cytosine is edited out to allow a functional transfer RNA structure to form.
A Yeast Hybrid Provides Insight into the Evolution of Gene Expression Regulation (1 May 2009)
I. Tirosh et al.
Gene expression between species of yeast may diverge, but recombination rewires their offspring into vigorous hybrids.
High-Throughput Sequencing of the Zebrafish Antibody Repertoire (8 May 2009)
J. A. Weinstein et al.
Sequencing of immunoglobulin messenger RNA characterizes the diversity of the antibody repertoire in individual zebrafish.
Direct Detection of Abortive RNA Transcripts in Vivo (15 May 2009)
S. R. Goldman et al.
RNA polymerase engages in abortive transcription in bacteria, a process that may help to regulate gene expression.
The Nuclear DNA Base 5-Hydroxymethylcytosine Is Present in Purkinje Neurons and the Brain (15 May 2009)
S. Kriaucionis and N. Heintz
The genome of mammals contains appreciable amounts of a previously undescribed modified DNA base.
Conversion of 5-Methylcytosine to 5-Hydroxymethylcytosine in Mammalian DNA by MLL Partner TET1 (15 May 2009)
M. Tahiliani et al.
Methylated C bases, an important epigenetic mark in genomic DNA, can be enzymatically converted to 5-hydroxymethylcytosine.
A Functional Role for Transposases in a Large Eukaryotic Genome (15 May 2009)
M. Nowacki et al.
The ciliate Oxytricha uses transposase genes to influence thousands of DNA rearrangements required for proper development.
Genome-Wide Identification of Human RNA Editing Sites by Parallel DNA Capturing and Sequencing (29 May 2009)
J. B. Li et al.
Hundreds of new RNA editing sites are identified in the human genome.
Unstable Tandem Repeats in Promoters Confer Transcriptional Evolvability (29 May 2009)
M. D. Vinces et al.
Unstable repetitive DNA in the control regions of yeast genes modulates the evolution of chromatin structure and gene expression.
NEUROSCIENCE/PSYCHOLOGY
Burst Spiking of a Single Cortical Neuron Modifies Global Brain State (1 May 2009)
C. T. Li et al.
Stimulation of a single nerve cell triggers a switch between slow wave and rapid eye movement sleep.
Self-Control in Decision-Making Involves Modulation of the vmPFC Valuation System (1 May 2009)
T. A. Hare et al.
The neural circuitry underlying choice and self-control is revealed by modeling and brain imaging.
Representation of Confidence Associated with a Decision by Neurons in the Parietal Cortex (8 May 2009)
R. Kiani and M. N. Shadlen
Neurons in the primate parietal cortex encode information required to make a decision and also the certainty of that choice.
Movement Intention After Parietal Cortex Stimulation in Humans (8 May 2009)
M. Desmurget et al.
Stimulation of the parietal cortex causes subjects to report having moved, even in the absence of actual motor responses.
See related Perspective.
A Key Role for Similarity in Vicarious Reward (15 May 2009)
D. Mobbs et al.
A functional magnetic resonance imaging study reveals the interactions within the brain that modulate feelings of reward on seeing a similar person win a contest.
Input-Specific Spine Entry of Soma-Derived Vesl-1S Protein Conforms to Synaptic Tagging (15 May 2009)
D. Okada et al.
The protein Vesl-1S fulfills the synaptic tagging hypothesis for the maintenance of input-specific action of neuronal networks.
A Frazzled/DCC-Dependent Transcriptional Switch Regulates Midline Axon Guidance (15 May 2009)
L. Yang et al.
A single receptor in Drosophila is involved in two molecular strategies that coordinate axon guidance.
See related Perspective.
Fictive Reward Signals in the Anterior Cingulate Cortex (15 May 2009)
B. Y. Hayden et al.
Single neurons in the monkey cingulate cortex respond to fictive and experienced outcomes in the same way.
Extinction-Reconsolidation Boundaries: Key to Persistent Attenuation of Fear Memories (15 May 2009)
M.-H. Monfils et al.
Behavioral manipulations can reverse a learned fearful association in rats.
Phasic Firing in Dopaminergic Neurons Is Sufficient for Behavioral Conditioning (22 May 2009)
H.-C. Tsai et al.
High-frequency pulses in deep brain cells release dopamine and cause reward-related behavior in mice.
The Human K-Complex Represents an Isolated Cortical Down-State (22 May 2009)
S. S. Cash et al.
A characteristic electroencephalogram pattern seen during sleep is accompanied by a steep decline in neural activity.
Entropic Evidence for Linguistic Structure in the Indus Script (29 May 2009)
R. P. N. Rao et al.
Analysis of the pattern of symbols confirms the linguistic role of ancient signs.
High-Frequency, Long-Range Coupling Between Prefrontal and Visual Cortex During Attention (29 May 2009)
G. G. Gregoriou et al.
Synchrony in neuronal firing within a specific frequency range may regulate interactions between brain structures.
GENETICS
Neural Mechanisms of a Genome-Wide Supported Psychosis Variant (1 May 2009)
C. Esslinger et al.
A genetic polymorphism associated with schizophrenia conveys a risk for abnormal connectivity between brain regions.
Exchange of Genetic Material Between Cells in Plant Tissue Grafts (1 May 2009)
S. Stegemann and R. Bock
Plant genes can transfer between cells and across graft junctions, possibly explaining horizontal gene transfer.
The Genetic Structure and History of Africans and African Americans (22 May 2009)
S. A. Tishkoff et al.
A genetic study illuminates population history, as well as the relationships among and the origin of major language families.
BIOCHEMISTRY
Mammalian Expression of Infrared Fluorescent Proteins Engineered from a Bacterial Phytochrome (8 May 2009)
X. Shu et al.
An engineered infrared fluorescent protein derived from an extremophile bacterium gives a strong signal in mammalian cells.
ATP-Citrate Lyase Links Cellular Metabolism to Histone Acetylation (22 May 2009)
K. E. Wellen et al.
Histone acetylation and gene expression in mammals are modulated by glycolytic metabolism.
See related Perspective.
Crystal Structure of the Nuclear Export Receptor CRM1 in Complex with Snurportin1 and RanGTP (22 May 2009)
T. Monecke et al.
The structure of an exportin complex shows how nuclear transport complexes differentially recognize cargo.
Structural Basis of Transcription: Backtracked RNA Polymerase II at 3.4 Angstrom Resolution (29 May 2009)
D. Wang et al.
A backtracked RNA polymerase II reveals how the enzyme proofreads the RNA transcript.
MICROBIOLOGY
Benzothiazinones Kill Mycobacterium tuberculosis by Blocking Arabinan Synthesis (8 May 2009)
V. Makarov et al.
An isomerase required for cell-wall synthesis is a target for an alternative drug lead for tuberculosis treatment.
The SOS Response Controls Integron Recombination (22 May 2009)
É. Guerin et al.
Bacteria can mobilize antibiotic resistance under stressful conditions.
Topographical and Temporal Diversity of the Human Skin Microbiome (29 May 2009)
E. A. Grice et al.
The human skin provides a landscape of dry, damp, and greasy niches for a diversity of symbiotic microorganisms.
PLANT SCIENCE
Host Inhibition of a Bacterial Virulence Effector Triggers Immunity to Infection (8 May 2009)
V. Ntoukakis et al.
An enzyme in tomato targets bacterial virulence to change the outcome of infection from susceptibility to immunity.
Regulators of PP2C Phosphatase Activity Function as Abscisic Acid Sensors (22 May 2009)
Y. Ma et al.
Abscisic Acid Inhibits Type 2C Protein Phosphatases via the PYR/PYL Family of START Proteins (22 May 2009)
S.-Y. Park et al.
Links between two ancient multimember protein families signal responses to the plant hormone abscisic acid.
MEDICINE/EPIDEMIOLOGY
Development of a Second-Generation Antiandrogen for Treatment of Advanced Prostate Cancer (8 May 2009)
C. Tran et al.
A drug that binds to the androgen receptor acts by disrupting its activity in the cell nucleus.
Understanding the Spreading Patterns of Mobile Phone Viruses (22 May 2009)
P. Wang et al.
Current mobile phone usage prevents major mobile virus outbreaks, but conditions could arise leading to a phone epidemic.
See related Perspective.