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This press release is copyright Nature.
VOL.451 NO.7178 DATED 31 JANUARY 2008
This press release contains:
· Summaries of newsworthy papers:
Antivirals: Insight into drug resistance of flu virus
Neuroscience: New cells’ effect on learning
Molecular medicine: Sugar rush to protect the heart
Nanotechnology: DNA blueprint for crystallization
Hurricanes: The temperature contribution
Materials science: Piezoelectric pressure point
Molecular biology: Controlling a double-edged sword
And finally... Insight into a doublet of giant earthquakes
· Mention of papers to be published at the same time with the same embargo
· Geographical listing of authors
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[1] & [2] Antivirals: Insight into drug resistance of flu virus (pp 591-595; 596-599; N&V)
Influenza A virus is a global health threat that is becoming seriously resistant to treatment with antiviral drugs, with resistance to the drug staples amantadine and rimantadine now standing at 90 per cent in humans, birds and pigs. Two papers published in Nature this week look at this problem, with contrasting results.
Two teams - James Chou and Jason Schnell, and William DeGrado and colleagues - look at the structure of a crucial channel in the membrane of the influenza virus. They investigate how the channel, known as M2, is targeted by adamantanes, inhibiting it and preventing the virus from replicating. They agree on the overall architecture of the channel, but suggest different mechanisms for its inhibition.
DeGrado and colleagues show that one of these drugs binds to the internal pore of the channel, whereas Schnell and Chou suggest that the drug they use inhibits the channel by binding from to an exterior surface. Further work is needed to establish which mechanism is more promising as a drug target; these contradictory results will stimulate both basic and clinical research into influenza.
CONTACT
James Chou (Harvard Medical School, Boston, MA, USA) Author paper [1]
Tel: +1 617 432 2920; E-mail: [email protected]
Jason Schnell (Harvard Medical School Boston, MA, USA) Co-author paper [1]
Tel: +1 617 432 4306; E-mail: [email protected]
William DeGrado (University of Pennsylvania School of Medicine, Philadelphia, PA, USA) Author paper [2]
Tel: +1 215 898 4590; E-mail: [email protected]
Christopher Miller (Howard Hughes Medical Institute, Waltham, MA, USA) N&V author
[3] Neuroscience: New cells’ effect on learning
DOI: 10.1038/nature06562
***This paper will be published electronically on Nature's website on 30 January at 1800 London time / 1300 US Eastern time (which is also when the embargo lifts) as part of our AOP (ahead of print) programme. Although we have included it on this release to avoid multiple mailings it will not appear in print on 31 January, but at a later date. ***
The deletion of a protein required for the proliferation of adult neural stem cells in mice appears to affect spatial learning and memory. It did not, however affect functions such as fear conditioning and movement. The research, published online in Nature this week, suggests that the ability to generate new neural cells in the brain is necessary for selective brain functions.
The production of new neurons occurs in the adult brain, and appears to be stimulated by external stimuli such as learning, memory, exercise and stress. It is known that neural stem cells express a nuclear receptor known as TLX. In order to test the effect of deleting neural stem cells, Ronald Evans and colleagues create a mouse model without TLX and show that the mice have reduced stem cell proliferation as well as a marked decrease in spatial learning. The fact that other behaviours were not affected suggested that newly born neurons have a selective contribution to brain functions.
CONTACT
Ronald Evans (The Salk Institute, La Jolla, CA, USA)
Tel: +1 858 453 4100 x1302; E-mail: [email protected]
[4] Molecular medicine: Sugar rush to protect the heart (pp 578-582)
During a heart attack, the organ struggles to pump blood and maintain its own oxygen supply so that it can continue to function. A paper in this week’s Nature uncovers an emergency strategy that the heart muscle uses to protect itself under such circumstances — enlisting molecules that help to keep it supplied with vital energy.
A catalytic protein known as AMP-activated protein kinase (AMPK) steps in when the heart is under stress to boost its uptake of glucose to prevent damage and cell death. But what triggers this rescue? Lawrence Young and colleagues reveal that a key participant is a molecule called macrophage migration inhibitory factor (MIF), which is normally involved in perpetrating unpleasant inflammatory diseases such as asthma and rheumatoid arthritis. Its production is stepped up as the oxygen-starved heart starts to flag, forcing AMPK into overdrive to come to its aid.
The authors suggest that in some people MIF may be less effective and that genetic analysis might one day allow us to predict risk in patients with coronary artery disease. It may also become possible to boost MIF activity to speed delivery of the rescue package.
CONTACT
Lawrence Young (Yale University, New Haven, CT, USA)
Tel: +1 203 785 4102; E-mail: [email protected]
[5] & [6] Nanotechnology: DNA blueprint for crystallization (pp 553-556; 549-552; N&V)
Simple nanoscale building blocks can self-assemble into ordered structures, but it isn’t an easy matter to precisely position different types of building blocks in three dimensions. Two papers in this week’s Nature describe the programming of encodable interactions between building blocks to this end - achieved by exploiting the recognition capabilities of DNA base pairing to direct assembly.
Chad Mirkin and colleagues tune the interactions between DNA molecules attached to gold nanoparticles and separate DNA linkers to drive the particles to assemble into different crystals with a well-defined symmetry. Oleg Gang and colleagues, in contrast, allow complementary DNA strands attached to nanoparticle surfaces to interact directly with each other and thereby realize crystals with an open structure that can be tuned by temperature.
The hope now is to extend the approach to make new classes of ordered multicomponent materials with useful properties.
CONTACT
Chad Mirkin (Northwestern University, Evanston, IL, USA) Author paper [5]
Tel: +1 847 491 2907; E-mail: [email protected]
Oleg Gang (Brookhaven National Laboratory, Upton, NY, USA) Author paper [6]
Tel: +1 631 344 3645; E-mail: [email protected]
John C. Crocker (University of Pennsylvania, Philadelphia, PA, USA) N&V author
Tel: +1 215 898 9188; E-mail: [email protected]
[7] Hurricanes: The temperature contribution (pp 557-560)
Local sea surface warming was responsible for about forty per cent of the increase in Atlantic hurricane activity (relative to the 1950-2000 average) between 1996 and 2005. A report in this week’s Nature quantifies, for the first time, the contribution that rising sea surface temperatures have made to recent changes in hurricane activity in the tropical North Atlantic.
Atlantic hurricane activity has increased significantly since 1995, but the underlying causes are still not fully understood. The rise in activity could reflect natural variations in the North Atlantic Ocean, or be linked more directly to global warming. In order to understand the causes, it is important to understand the separate contributions of atmospheric circulation and sea surface temperatures.
Mark Saunders and Adam Lea attempt to quantify these contributions for storms that formed in the tropical North Atlantic, Caribbean Sea and Gulf of Mexico - the origin of most hurricanes that hit the United States. They use a statistical model based on two environmental factors - local sea surface temperature and an atmospheric wind field - to replicate hurricane activity and frequency for the last forty years. By removing the influence of atmospheric wind field, the authors find that the increase in sea surface temperature between 1996 and 2005 was responsible for about forty per cent of the increase in hurricane activity during this period.
The study does not show whether greenhouse-gas-induced warming contributed to this increase or how hurricane activity will respond to future climate change, but the ability of climate models to reproduce these relationships may serve as a useful means for assessing their reliability.
CONTACT
Mark Saunders (University College London, Surrey, UK)
Tel: +44 1483 204 187; E-mail: [email protected]
Adam Lea (University College London, Surrey, UK)
Tel: +44 1483 204 217; E-mail: [email protected] Co-author
[8] Materials science: Piezoelectric pressure point
Apply a mechanical force to a piezoelectric material and you generate a voltage; conversely, apply a voltage and you get a force - a combination of properties that has a wealth of applications, notably in ultrasound technology. A paper in this week’s Nature describes one such system that is surprisingly simple, yet generates an electromechanical response larger than any known so far.
Materials that give the best electromechanical responses generally have a highly complex structure and composition, and the desired properties tend to be optimal when associated with a 'morphotropic' phase transition - an abrupt change in the structure of the material, usually in response to changes in its composition. However, Muhtar Ahart and colleagues show that a morphotropic transition can also occur in a simple, pure compound (here, lead titanate) when it is under high pressure, and that the change is accompanied by a most impressive electromechanical response.
The team also explain how these effects might soon be realised without the need for high pressures - a development that could reduce costs and enhance the utility of high-performance piezoelectric materials for ultrasonics in medicine, sonar and hydrophones, to name only a few applications.
CONTACT
Muhtar Ahart (Carnegie Institution of Washington, Washington, DC, USA)
Tel: +1 202 478 8932; E-mail: [email protected]
[9] & [10] Molecular biology: Controlling a double-edged sword (pp 583-586; 587-590)
A protein known as SIRT1 has an important role in the cell, but it is something of a double-edged sword - implicated in both combating ageing and promoting tumour growth, its activity needs to be tightly controlled. Two papers in this week’s Nature offer valuable insight into how this key protein is regulated.
The two groups, respectively comprising Junjie Chen and Wei Gu and their colleagues, have discovered that another protein, named DBC1, acts as a regulator of SIRT1 activity. DBC1 prevents SIRT1 from carrying out its normal function of removing special chemical tags, called acetyl groups, from other proteins inside the cell. The acetylation status of a molecule influences its particular function - for better or for worse - hence the seemingly duplicitous role of SIRT1.
By inhibiting SIRT1, DBC1 allows damaged cells to self-destruct, which would be beneficial in combating cancer cells. It also makes normal cells more susceptible to oxidative stress, so agents designed to inhibit or activate SIRT1 could each be beneficial, depending on circumstances.
CONTACT
Junjie Chen (Yale University, New Haven, CT, USA) Author paper [9]
Tel: +1 203 785 3758; E-mail: [email protected]
Wei Gu (Columbia University, New York, NY, USA) Author paper [10]
Tel: +1 212 851 8252; E-mail: [email protected]
[11] And finally... Insight into a doublet of giant earthquakes (pp 561-565)
Just occasionally a large earthquake is followed soon afterwards by another of comparable magnitude - a phenomenon known as an earthquake doublet. A paper in this week’s Nature analyses one such series of events that took place in the Kuril Islands off northern Japan towards the end of 2006 and in early 2007 - the second largest doublet on record after the 2004-05 Sumatra earthquakes.
Thorne Lay and colleagues quantify features of this remarkable seismic doublet, which involved rupture of two different faults only 100 kilometres or so apart and within two months of one another - first an earthquake occurring between the subducting Pacific plate and overriding Kuril islands, followed by another giant quake within the Pacific plate itself. This dramatic sequence reveals the seismic stress transfer within the oceanic crust and how such earthquakes can be triggered.
Despite their large size, the doublet generated only modest tsunamis, each under two metres high. But the scars from the doublet may host many future earthquakes.
CONTACT
Thorne Lay (University of California, Santa Cruz, CA, USA)
Tel: +1 831 459 3164; E-mail: [email protected]
ALSO IN THIS ISSUE
[12] A test of the nature of cosmic acceleration using galaxy redshift distortions (pp 541-544; N&V)
ADVANCE ONLINE PUBLICATION
***These papers will be published electronically on Nature's website on 30 January at 1800 London time / 1300 US Eastern time (which is also when the embargo lifts) as part of our AOP (ahead of print) programme. Although we have included them on this release to avoid multiple mailings they will not appear in print on 31 January, but at a later date. ***
[13] The X-ray crystal structure of RNA polymerase from Archaea
DOI: 10.1038/nature06530
[14] Cohesin mediates transcriptional insulation by CCCTC-binding factor
DOI: 10.1038/nature06634
[15] A modular switch for spatial Ca21 selectivity in the calmodulin regulation of CaV channels
DOI: 10.1038/nature06529
GEOGRAPHICAL LISTING OF AUTHORS
The following list of places refers to the whereabouts of authors on the papers numbered in this release. For example, London: 4 - this means that on paper number four, there will be at least one author affiliated to an institute or company in London. The listing may be for an author's main affiliation, or for a place where they are working temporarily. Please see the PDF of the paper for full details.
AUSTRIA
Vienna: 14
FRANCE
Marseille: 12
Paris: 12
Toulouse: 12
GERMANY
Garching: 12
Potsdam: 12
ITALY
Bologna: 12
Merate: 12
Milan: 12
Naples: 12
Rome: 12
JAPAN
Kanagawa: 14
Kumamoto: 14
Osaka: 14
Saitama: 14
Sapporo: 4
Tokyo: 14
POLAND
Warsaw: 12
SWITZERLAND
Sauverny: 12
Versoix: 12
Zurich: 2
UNITED KINGDOM
Nottingham: 12
Surrey: 7
UNITED STATES OF AMERICA
California
Berkeley: 8
La Jolla: 3
Pasadena: 11
Santa Cruz: 11
Connecticut
New Haven: 4, 9
District of Columbia
Washington: 8
Hawaii
Honolulu: 12
Illinois
Argonne: 5, 8
Chicago: 2
Evanston: 5
Maryland
Baltimore: 15
Massachusetts
Boston: 1
Minnesota
Rochester: 9
New Jersey
Piscataway: 2
New York
New York: 10
Rochester: 5
Upton: 6
Pennsylvania
Philadelphia: 2
University Park: 11, 13
Rhode Island
Providence: 2
Texas
Houston: 3, 10
Wyoming
Laramie: 4
PRESS CONTACTS
For North America and Canada
Katie McGoldrick, Nature Washington
Tel: +1 202 737 2355; E-mail: [email protected]
For Japan, Korea, China, Singapore and Taiwan
Mika Nakano, Nature Tokyo
Tel: +81 3 3267 8751; E-mail: [email protected]
For the UK/Europe/other countries not listed above
Katherine Anderson, Nature London
Tel: +44 20 7843 4502; E-mail [email protected]
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