This month in Bio-Med Roundup:

• Lesurtel et al . and Huang et al . showed that serotonin and bile acid signaling are required for liver regeneration.
• D'Angelo et al . showed that nuclear pores form de novo from both sides of the nuclear envelope.
• Terszowski et al . found that mice have a second thymus that contributes functional T cells to the immune system.
• Riehle et al . identified a cluster of mosquito genes that confer resistance to the malaria parasite in many wild mosquitoes.

• Development
• Biochemistry
• Cell Biology
• Immunology
• Plant Science
• Medicine
• Genetics
• Microbiology/Virology
• Evolution

DEVELOPMENT

Zebrafish MiR-430 Promotes Deadenylation and Clearance of Maternal mRNAs (7 April 2006 )
A. J. Giraldez, Y. Mishima, J. Rihel, R. J. Grocock, S. Van Dongen, K. Inoue, A. J. Enright, A. F. Schier
A small regulatory RNA promotes the degradation of the maternal messenger RNAs that are packaged into the oocyte to guide the first steps of animal development.
http://www.sciencemag.org/cgi/content/abstract/312/5770/75
See related Perspective at http://www.sciencemag.org/cgi/content/summary/312/5770/65

Platelet-Derived Serotonin Mediates Liver Regeneration (7 April 2006)
M. Lesurtel, R. Graf, B. Aleil, D. J. Walther, Y. Tian, W. Jochum, C. Gachet, M. Bader, P.-A. Clavien
In mice, regeneration of damaged liver tissue unexpectedly requires the neurotransmitter serotonin carried by circulating blood platelets.
http://www.sciencemag.org/cgi/content/abstract/312/5770/104

Nuclear Receptor–Dependent Bile Acid Signaling Is Required for Normal Liver Regeneration (14 April 2006)
W. Huang, K. Ma, J. Zhang, M. Qatanani, J. Cuvillier, J. Liu, B. Dong, X. Huang, D. D. Moore
After injury to the liver, accumulated bile induces liver regeneration in mice, providing one mechanism for control of organ size.
http://www.sciencemag.org/cgi/content/abstract/312/5771/233

Retinoid Signaling Determines Germ Cell Fate in Mice (28 April 2006)
J. Bowles, D. Knight, C. Smith, D. Wilhelm, J. Richman, S. Mamiya, K. Yashiro, K. Chawengsaksophak et al.
The hormone retinoid triggers meiosis in the germ cells of the mouse ovary, stimulating oocyte formation; retinoid is degraded in the testis, allowing the generation of sperm.
http://www.sciencemag.org/cgi/content/abstract/312/5773/596



BIOCHEMISTRY

Atomic Description of an Enzyme Reaction Dominated by Proton Tunneling (14 April 2006)
L. Masgrau, A. Roujeinikova, L. O. Johannissen, P. Hothi, J. Basran, K. E. Ranaghan, A. J. Mulholland, M. J. Sutcliffe, N. S. Scrutton, D. Leys
Proton transfer during enzymatic tryptamine oxidation proceeds by tunneling, which occurs over ~0.6 Å and is modulated by short-range thermal motions.
http://www.sciencemag.org/cgi/content/abstract/312/5771/237
See related Perspective at http://www.sciencemag.org/cgi/content/summary/312/5771/208

Conformational Switches Modulate Protein Interactions in Peptide Antibiotic Synthetases ( 14 April 2006 )
A. Koglin, M. R. Mofid, F. Löhr, B. Schäfer, V. V. Rogov, M.-M. Blum, T. Mittag, M. A. Marahiel, F. Bernhard, V. Dötsch
Changes in the structure of a peptide carrier protein that holds a growing peptide chain directs the nonribosomal synthesis of certain antibiotics.
http://www.sciencemag.org/cgi/content/abstract/312/5771/273

A Voltage Sensor–Domain Protein Is a Voltage-Gated Proton Channel ( 28 April 2006 )
M. Sasaki, M. Takagi, Y. Okamura
Most of a voltage-gated protein proton channel consists of a four transmembrane domain similar to the voltage sensor of other channels.
http://www.sciencemag.org/cgi/content/abstract/312/5773/589
See related Perspective at http://www.sciencemag.org/cgi/content/summary/312/5773/534



CELL BIOLOGY

Nuclear Pores Form de Novo from Both Sides of the Nuclear Envelope (21 April 2006)
M. A. D'Angelo, D. J. Anderson, E. Richard, M. W. Hetzer
The protein pores that transport molecules through the double-bilayered membrane of the cell nucleus form in situ, with constituents contributed from both sides.
http://www.sciencemag.org/cgi/content/abstract/312/5772/440

Differential Targeting of Gß? -Subunit Signaling with Small Molecules (21 April 2006)
T. M. Bonacci, J. L. Mathews, C. Yuan, D. M. Lehmann, S. Malik, D. Wu, J. L. Font, J. M. Bidlack, A. V. Smrcka
A screen for small molecules that bind to the interaction region of a key signaling protein yields several that selectively inhibit individual downstream pathways.
http://www.sciencemag.org/cgi/content/abstract/312/5772/443
See related Perspective at http://www.sciencemag.org/cgi/content/summary/312/5772/377

Proapoptotic BAX and BAK Modulate the Unfolded Protein Response by a Direct Interaction with IRE1a ? (28 April 2006)
C. Hetz, P. Bernasconi, J. Fisher, A.-H. Lee, M. C. Bassik, B. Antonsson, G.S. Brandt, N. N. Iwakoshi, A. Schinzel, L. H. Glimcher, S. J. Korsmeyer
Two proteins that act at mitochondria to trigger cell death when cells are damaged also promote survival responses at the endoplasmic reticulum when cells are under stress.
http://www.sciencemag.org/cgi/content/abstract/312/5773/572



IMMUNOLOGY

Naïve and Memory CD4+ T Cell Survival Controlled by Clonal Abundance (7 April 2006)
J. Hataye, J. J. Moon, A. Khoruts, C. Reilly, M. K. Jenkins
Clonal subpopulations of immune T cells—each of which binds to a different antigen—are more stable if they contain smaller numbers of cells.
http://www.sciencemag.org/cgi/content/abstract/312/5770/114

Evidence for a Functional Second Thymus in Mice ( 14 April 2006 )
G. Terszowski, S. M. Müller, C. C. Bleul, C. Blum, R. Schirmbeck, J. Reimann, L. Du Pasquier, T. Amagai, T. Boehm, H.-R. Rodewald
Mice have a second thymus in the neck that contributes functional T cells to the immune system.
http://www.sciencemag.org/cgi/content/abstract/312/5771/284
See related Perspective at http://www.sciencemag.org/cgi/content/summary/312/5771/206

RNA Interference Directs Innate Immunity Against Viruses in Adult Drosophila ( 21 April 2006 )
X.-H. Wang, R. Aliyari, W.-X. Li, H.-W. Li, K. Kim, R. Carthew, P. Atkinson, S.-W. Ding
Insects use small RNA silencing mechanisms to neutralize invading viral pathogens.
http://www.sciencemag.org/cgi/content/abstract/312/5772/452



PLANT SCIENCE

A Bifurcating Pathway Directs Abscisic Acid Effects on Stomatal Closure and Opening in Arabidopsis (14 April 2006)
G. Mishra, W. Zhang, F. Deng, J. Zhao, X. Wang
A plant prevents dehydration by activating a phospholipase that inhibits opening of surface pores through one pathway and closes open ones through another.
http://www.sciencemag.org/cgi/content/abstract/312/5771/264

A Plant miRNA Contributes to Antibacterial Resistance By Repressing Auxin Signaling (21 April 2006)
L. Navarro, P. Dunoyer, F. Jay, B. Arnold, N. Dharmasiri, M. Estelle, O. Voinnet, J. D. G. Jones
Arabidopsis reacts to a bacterial infection by induction of a small RNA that inhibits signaling of a plant hormone, which in turn increases its resistance to the microbe.
http://www.sciencemag.org/cgi/content/abstract/312/5772/436

Autophagic Fungal Cell Death Is Necessary for Infection by the Rice Blast Fungus (28 April 2006)
C. Veneault-Fourrey, M. Barooah, M. Egan, G. Wakley, N. J. Talbot
For successful infection, a serious fungal pathogen of rice builds specialized cellular structures that pierce the plant cuticle, a process that requires autophagic cell death.
http://www.sciencemag.org/cgi/content/abstract/312/5773/580



MEDICINE

Losartan, an AT1 Antagonist, Prevents Aortic Aneurysm in a Mouse Model of Marfan Syndrome (7 April 2006)
J. P. Habashi, D. P. Judge, T. M. Holm, R. D. Cohn, B. L. Loeys, T. K. Cooper, L. Myers, E. C. Klein, G. Liu, C. Calvi et al.
Amouse study suggests that life-threatening heart defects in patients with Marfan syndrome may be preventable by losartan, a drug widely given for high blood pressure.
http://www.sciencemag.org/cgi/content/abstract/312/5770/117

Synchrony, Waves, and Spatial Hierarchies in the Spread of Influenza (21 April 2006)
C. Viboud, O. N. Bjørnstad, D. L. Smith, L. Simonsen, M. A. Miller, B. T. Grenfell
Thirty years of data indicate that in the United States , seasonal flu epidemics often spread by adult-to-adult transfer during commuting on public transportation.
http://www.sciencemag.org/cgi/content/abstract/312/5772/447

SV2 Is the Protein Receptor for Botulinum Neurotoxin A (28 April 2006)
M. Dong, F. Yeh, W. H. Tepp, C. Dean, E. A. Johnson, R. Janz, E. R. Chapman
One of the toxins from botulinum enters neurons by hitching a ride on proteins that are exposed when synaptic vesicles release neurotransmitters and are then recycled.
http://www.sciencemag.org/cgi/content/abstract/312/5773/592
See related Perspective at http://www.sciencemag.org/cgi/content/summary/312/5773/540



GENETICS

CTCF Mediates Interchromosomal Colocalization Between Igf2/H19 and Wsb1/Nf1 (14 April 2006)
J. Q. Ling, T. Li, J. F. Hu, T. H. Vu, H. L. Chen, X. W. Qiu, A. M. Cherry, A. R. Hoffman
A DNA binding protein brings gene sequences from different chromosomes to a common, transcriptionally active region of the nucleus.
http://www.sciencemag.org/cgi/content/abstract/312/5771/269
See related Perspective at http://www.sciencemag.org/cgi/content/summary/312/5771/207

A Common Genetic Variant Is Associated with Adult and Childhood Obesity (14 April 2006)
A. Herbert, N. P. Gerry, M. B. McQueen, I. M. Heid, A. Pfeufer, T. Illig, H.-E. Wichmann, T. Meitinger, D. Hunter, F. B. Hu et al.
A common nucleotide variation is associated with obesity in subjects from a 24-year longitudinal heart study and in four other independent groups.
http://www.sciencemag.org/cgi/content/abstract/312/5771/279

Natural Malaria Infection in Anopheles gambiae Is Regulated by a Single Genomic Control Region (28 April 2006)
M. M. Riehle, K. Markianos, O. Niaré, J. Xu, J. Li, A. M. Touré, B. Podiougou, F. Oduol, S. Diawara, M. Diallo et al.
A cluster of mosquito genes similar to innate immunity genes from other species confers resistance to the malaria parasite in a large proportion of wild mosquitoes.
http://www.sciencemag.org/cgi/content/abstract/312/5773/577



MICROBIOLOGY / VIROLOGY

H5N1 Virus Attachment to Lower Respiratory Tract (21 April 2006)
D. van Riel, V. J. Munster, E. de Wit, G. F. Rimmelzwaan, R. A. M. Fouchier, A. D. M. E. Osterhaus, T. Kuiken
Avian influenza H5N1 attaches most efficiently to cell types located deep in the lungs of some mammals, influencing pathology and transmissibility.
http://www.sciencemag.org/cgi/content/abstract/312/5772/399

Structure and Receptor Specificity of the Hemagglutinin from an H5N1 Influenza Virus (21 April 2006)
J. Stevens, O. Blixt, T. M. Tumpey, J. K. Taubenberger, J. C. Paulson, I. A. Wilson
A surface protein on the “bird flu” virus binds avian cells and with a few mutations could allow more avid attachment to human cells, facilitating infection.
http://www.sciencemag.org/cgi/content/abstract/312/5772/404

Global Control of Dimorphism and Virulence in Fungi ( 28 April 2006 )
J. C. Nemecek, M. Wüthrich, B. S. Klein
When fungal spores are inhaled, a regulatory receptor senses the host environment and shifts their morphology from a filamentous to a virulent yeast form.
http://www.sciencemag.org/cgi/content/abstract/312/5773/583



EVOLUTION

Evolution of Hormone-Receptor Complexity by Molecular Exploitation (7 April 2006)
J. T. Bridgham, S. M. Carroll, J. W. Thornton
A steroid receptor developed its modern specificity by changes in two amino acids, followed by modification of a steroid biosynthetic enzyme to make its ligand.
http://www.sciencemag.org/cgi/content/abstract/312/5770/97
See related Perspective at http://www.sciencemag.org/cgi/content/summary/312/5770/61

Darwinian Evolution Can Follow Only Very Few Mutational Paths to Fitter Proteins (7 April 2006)
D. M. Weinreich, N. F. Delaney, M. A. DePristo, D. L. Hartl
Of 120 ways in which an enzyme can sequentially acquire five mutations that together confer drug resistance, 102 fail because the intermediate combinations decrease fitness.
http://www.sciencemag.org/cgi/content/abstract/312/5770/111

Conservation of RET Regulatory Function from Human to Zebrafish Without Sequence Similarity (14 April 2006)
S. Fisher, E. A. Grice, R. M. Vinton, S. L. Bessling, A. S. McCallion
A human regulatory gene can substitute for the corresponding gene in zebrafish, conferring tissue-specific expression, despite its different sequence.
http://www.sciencemag.org/cgi/content/abstract/312/5771/276