• Cell/Developmental Biology
• Molecular Biology
• Biochemistry
• Biomedicine
• Neuroscience
• Immunology
• Plant Science
• Physiology
• Sociology/Psychology

This month’s Bio-Med Roundup is sponsored by:
The Biomarker Discovery Webinar - June 20, 2007

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CELL/DEVELOPMENTAL BIOLOGY
 
Blastocyst Axis Is Specified Independently of Early Cell Lineage But Aligns with the ZP Shape (4 May 2007)
Y. Kurotaki, K. Hatta, K. Nakao, Y. Nabeshima, T. Fujimori
Time-lapse imaging shows that the axis of the mouse embryo is not specified intrinsically but is influenced by the shape of the overlying zona pellucida.
See related Perspective.

Positive Regulation of Itk PH Domain Function by Soluble IP₄ (11 May 2007)
Y. H. Huang, J. A. Grasis, A. T. Miller, R. Xu, S. Soonthornvacharin, A. H. Andreotti, C. D. Tsoukas, M. P. Cooke, K. Sauer
A kinase phosphorylates the inositol pyrophosphate IP₃ to generate IP₄ and is necessary for cell signaling during positive selection of immune cells.
See related Perspective.

The After-Hours Mutant Reveals a Role for Fbxl3 in Determining Mammalian Circadian Period (11 May 2007)
S. I. H. Godinho, E. S. Maywood, L. Shaw, V. Tucci, A. R. Barnard, L. Busino, M. Pagano, R. Kendall, M. M. Quwailid, M. R. Romero et al.

SCF_Fbxl3 Controls the Oscillation of the Circadian Clock by Directing the Degradation of Cryptochrome Proteins (11 May 2007)
L. Busino, F. Bassermann, A. Maiolica, C. Lee, P. M. Nolan, S. I. H. Godinho, G. F. Draetta, M. Pagano
Genetic and biochemical screens identify the same protein, which determines period length of the circadian clock by degradation of a known component.

Revisiting the Role of the Mother Centriole in Centriole Biogenesis (18 May 2007)
A. Rodrigues-Martins, M. Riparbelli, G. Callaini, D. M. Glover, M. Bettencourt-Dias
New centrioles can form in the absence of an existing centriole, showing that the process occurs by template-free self-assembly.

Wilms Tumor Suppressor WTX Negatively Regulates WNT/β Catenin Signaling (18 May 2007)
M. B. Major, N. D. Camp, J. D. Berndt, X. Yi, S. J. Goldenberg, C. Hubbert, T. L. Biechele, A.C. Gingras, N. Zheng, M. J. MacCoss et al.
Analysis of a protein interaction network reveals that a newly identified tumor suppressor for pediatric kidney cancer is part of an important developmental signaling cascade.
See related Perspective.

ATM and ATR Substrate Analysis Reveals Extensive Protein Networks Responsive to DNA Damage (25 May 2007)
S. Matsuoka, B. A. Ballif, A. Smogorzewska, E. R. McDonald, III, K. E. Hurov, J. Luo, C. E. Bakalarski, Z. Zhao, N. Solimini, Y. Lerenthal et al.
A proteomic analysis reveals that DNA damage induces phosphorylation of hundreds of proteins, many of which were not previously associated with this response.
See related Perspective.

How Synaptotagmin Promotes Membrane Fusion (25 May 2007)
S. Martens, M. M. Kozlov, H. T. McMahon
A synaptic vesicle protein completes the final steps of membrane fusion by causing membrane curvature when triggered by a pulse of calcium.


MOLECULAR BIOLOGY

Developmentally Regulated piRNA Clusters Implicate MILI in Transposon Control (4 May 2007)
A. A. Aravin, R. Sachidanandam, A. Girard, K. Fejes-Toth, G. J. Hannon
A small class of RNA found only in the germ line helps to suppress transposons—parasitic DNA elements—in mice, as they do in Drosophila.

Combined Action of PHD and Chromo Domains Directs the Rpd3S HDAC to Transcribed Chromatin (18 May 2007)
B. Li, M. Gogol, M. Carey, D. Lee, C. Seidel, J. L. Workman
A binding protein can maintain chromatin in a deacetylated, transcription-ready state only when complexed with another chromatin protein.

Abraxas and RAP80 Form a BRCA1 Protein Complex Required for the DNA Damage Response (25 May 2007)
B. Wang, S. Matsuoka, B. A. Ballif, D. Zhang, A. Smogorzewska, S. P. Gygi, S. J. Elledge
The breast cancer tumor suppressor BRCA1 is recruited to sites of DNA damage by partner proteins that help it to recognize ubiquitinated proteins.
See related Perspective.

RAP80 Targets BRCA1 to Specific Ubiquitin Structures at DNA Damage Sites (25 May 2007)
B. Sobhian, G. Shao, D. R. Lilli, A. C. Culhane, L. A. Moreau, B. Xia, D. M. Livingston, R. A. Greenberg

Ubiquitin-Binding Protein RAP80 Mediates BRCA1-Dependent DNA Damage Response (25 May 2007)
H. Kim, J. Chen, X. Yu
A ubiquitin-binding protein targets the breast cancer tumor suppressor BRCA1 to sites of DNA damage and is required for the subsequent arrest of the cell cycle.
See related Perspective.


BIOCHEMISTRY

Protein Dynamics Control the Kinetics of Initial Electron Transfer in Photosynthesis (4 May 2007)
H. Wang, S. Lin, J. P. Allen, J. C. Williams, S. Blankert, C. Laser, N. W. Woodbury
The initial charge separation in photosynthesis is limited by protein motion, rather than by a static electron transfer rate.
See related Perspective.

Conformational Switching in the Fungal Light Sensor Vivid (18 May 2007)
B. D. Zoltowski, C. Schwerdtfeger, J. Widom, J. J. Loros, A. M. Bilwes, J. C. Dunlap, B. R. Crane
When a flavin-based photoreceptor absorbs a photon, large-scale conformational changes at the protein N terminus initiate functional changes.

A Manganese(IV)/Iron(III) Cofactor in Chlamydia trachomatis Ribonucleotide Reductase (25 May 2007)
W. Jiang, D. Yun, L. Saleh, E. W. Barr, G. Xing, L. M. Hoffart, M.A. Maslak, C. Krebs, J. M. Bollinger, Jr.
A pathogenic bacterium makes DNA precursors via an enzyme with a high-valent metal center; this helps it elude the human immune system and may mimic the RNA world.

Probing Transcription Factor Dynamics at the Single-Molecule Level in a Living Cell (25 May 2007)
J. Elf, G.W. Li, X. S. Xie
A repressor protein in Escherichia coli spends about 90 percent of its time diffusing along DNA, falling off and trying again if it does not find its specific binding site within 5 ms.

Myosin V Walks by Lever Action and Brownian Motion (25 May 2007)
K. Shiroguchi and K. Kinosita Jr.
As a two-headed molecular motor walks along actin, the bound leading head biases the rotational Brownian motion of the unbound head so that it lands on a forward site.


BIOMEDICINE
 
Reducing Endogenous Tau Ameliorates Amyloid β–Induced Deficits in an Alzheimer’s Disease Mouse Model (4 May 2007)
E. D. Roberson, K. Scearce-Levie, J. J. Palop, F. Yan, I. H. Cheng, T. Wu, H. Gerstein, G.Q. Yu, L. Mucke
Mice with cognitive deficits resembling Alzheimer’s disease show improvement when levels of a protein found in neurofibrillary tangles are transgenically reduced.

A Common Variant in the FTO Gene Is Associated with Body Mass Index and Predisposes to Childhood and Adult Obesity (11 May 2007)
T. M. Frayling, N. J. Timpson, M. N. Weedon, E. Zeggini, R. M. Freathy, C. M. Lindgren, J. R. B. Perry, K. S. Elliott, H. Lango, N. W. Rayner et al.
A common variant of a gene that increases the risk of obesity by ~67 percent is consistently associated with body mass index in 13 studies involving over 38,000 subjects.

MET Amplification Leads to Gefitinib Resistance in Lung Cancer by Activating ERBB3 Signaling (18 May 2007)
J. A. Engelman, K. Zejnullahu, T. Mitsudomi, Y. Song, C. Hyland, J. O. Park, N. Lindeman, C.M. Gale, X. Zhao, J. Christensen et al.
Human lung cancers can become resistant to a kinase inhibitor by producing multiple copies of a gene in the same pathway, bypassing the inhibited step.


NEUROSCIENCE
 
Specialized Inhibitory Synaptic Actions Between Nearby Neocortical Pyramidal Neurons (4 May 2007)
M. Ren, Y. Yoshimura, N. Takada, S. Horibe, Y. Komatsu
Unexpectedly, the main excitatory neurons in the mouse cortex strongly inhibit each other via axon-to-axon activation of inhibitory interneurons.

How the Brain Translates Money into Force: A Neuroimaging Study of Subliminal Motivation (11 May 2007)
M. Pessiglione, L. Schmidt, B. Draganski, R. Kalisch, H. Lau, R. J. Dolan, C. D. Frith
Promise of a reward, even when perceived only subliminally, engages a specific brain region and thereby increases the effort put into a task.

Hardwiring the Brain: Endocannabinoids Shape Neuronal Connectivity (25 May 2007)
P. Berghuis, A. M. Rajnicek, Y. M. Morozov, R. A. Ross, J. Mulder, G. M. Urbán, K. Monory, G. Marsicano, M. Matteoli, A. Canty et al.
Endocannabinoids can inhibit the growth of axons; mice without one type of cannabinoid receptor have more inhibitory neuronal inputs to cortical areas of the brain.


IMMUNOLOGY

Regulation of NF-ΚB Activation in T Cells via Association of the Adapter Proteins ADAP and CARMA1 (4 May 2007)
R. B. Medeiros, B. J. Burbach, K. L. Mueller, R. Srivastava, J. J. Moon, S. Highfill, E. J. Peterson, Y. Shimizu
An adapter protein that links antigen activation of immune cells to cell adhesion also acts through a signaling protein complex to induce immune response genes.

Regulation of B Versus T Lymphoid Lineage Fate Decision by the Proto-Oncogene LRF (11 May 2007)
T. Maeda, T. Merghoub, R. M. Hobbs, L. Dong, M. Maeda, J. Zakrzewski, M.R.M. van den Brink, A. Zelent, H. Shigematsu, K. Akashi et al.
Developing immune cells become antibody-producing cells through activation of a proto-oncogene that inhibits the alternative developmental pathway.
See related Perspective.


PLANT SCIENCE
 
Signals from Chloroplasts Converge to Regulate Nuclear Gene Expression (4 May 2007)
S. Koussevitzky, A. Nott, T. C. Mockler, F. Hong, G. Sachetto-Martins, M. Surpin, J. Lim, R. Mittler, J. Chory
In a critical regulatory loop for plants, damaged chloroplasts signal their status to the nucleus via a single signaling pathway and its key component, GUN1.
See related Perspective.

The Role of Wheat Awns in the Seed Dispersal Unit (11 May 2007)
R. Elbaum, L. Zaltzman, I. Burgert, P. Fratzl
The microstructure of hairlike awns on wheat seeds causes them to bend reversibly as humidity changes, propelling the seed along the ground and into the soil surface.

FT Protein Movement Contributes to Long-Distance Signaling in Floral Induction of Arabidopsis (18 May 2007)
L. Corbesier, C. Vincent, S. Jang, F. Fornara, Q. Fan, I. Searle, A. Giakountis, S. Farrona, L. Gissot, C. Turnbull, G. Coupland

Hd3a Protein Is a Mobile Flowering Signal in Rice (18 May 2007)
S. Tamaki, S. Matsuo, H. L. Wong, S. Yokoi, K. Shimamoto
The protein products of the genes Hd3a in rice and FT in Arabidopsism are the elusive florigen signals that move from leaf to shoot to induce flowering.

Dicamba Resistance: Enlarging and Preserving Biotechnology-Based Weed Management Strategies (25 May 2007)
M. R. Behrens, N. Mutlu, S. Chakraborty, R. Dumitru, W. Z. Jiang, B. J. LaVallee, P. L. Herman, T. E. Clemente, D. P. Weeks
Soybean and other crops engineered to be resistant to dicamba, an environmentally friendly herbicide, will be useful as weeds become resistant to other herbicides.


PHYSIOLOGY
 
Bat Flight Generates Complex Aerodynamic Tracks (11 May 2007)
A. Hedenström, L. C. Johansson, M. Wolf, R. von Busse, Y. Winter, G. R. Spedding
The wake of small flying bats shows multiple vortices when traced, suggesting that their flight is based on somewhat different principles than that of birds.

Sound Production in the Clownfish Amphiprion clarkii (18 May 2007)
E. Parmentier, O. Colleye, M. L. Fine, B. Frédérich, P. Vandewalle, A. Herrel
The loud sounds that clownfish make during territorial defense or mating are produced by percussive collisions of the teeth and the resulting vibrations of the jaw.


SOCIOLOGY/PSYCHOLOGY
 
The Increasing Dominance of Teams in Production of Knowledge (18 May 2007)
S. Wuchty, B. F. Jones, B. Uzzi
Teams of two or more people are increasingly producing more of the research, and the research they generate is more highly cited, in a wide variety of endeavors from science to the arts.

Visual Language Discrimination in Infancy (25 May 2007)
W. M. Weikum, A. Vouloumanos, J. Navarra, S. Soto-Faraco, N. Sebastián-Gallés, J. F. Werker
Before they are 8 months old, infants can tell whether someone is speaking French or English just by watching the speaker’s face, but afterward they lose this ability.