This month in *Science* Roundup:
Gene Fusion and Prostate Cancer
Cell Signaling Insight
Genetic Link to Tourette's
Appetite, Weight Loss, and the Brain
Sharks on the Move
Sustaining Mangroves and Aquaculture
Bats to Blame
Climate-Attuned Birds
Ice Sheets and Rising Seas
More Arctic Warming
Titan's Fleeting Clouds
Tracing Early Anthropoids
A Molecular Turnstile
From Metal to Insulator
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Gene Fusion and Prostate Cancer
Recurrent gene rearrangements are characteristic of many blood cancers including leukemias and lymphomas. Gene rearrangements also occur in the more common solid cancers such as breast, prostate, and colon cancers, but they are incredibly complex and were thought to occur randomly. Now a Report by Tomlin et al. (http://www.sciencemag.org/cgi/content/short/310/5748/644) in the 28 Oct 2005 *Science* provides the first evidence that recurrent gene fusion plays a widespread role in prostate cancer. Using a bioinformatics approach called COPA (cancer outlier profile analysis), the team showed that the majority of human prostate tumors exhibit chromosomal rearrangements that fuse either of two specific transcription factor genes with a segment of a prostate-specific gene called *TMPRSS2* and regulated by the male hormone androgen. The gene fusion results in overexpression of the transcription factor genes. The new findings may have important implications for understanding how prostate cancer arises and for developing novel diagnostic tools and therapeutics. A News story by J. Marx (http://www.sciencemag.org/cgi/content/short/310/5748/603a) highlighted the report.
http://www.sciencemag.org/sciext/cellsignaling05/
In the 7 Oct 2005 issue, *Science* Magazine and its online Signal Transduction Knowledge Environment (STKE; http://stke.sciencemag.org/) joined forces to provide a fresh look at developments in cell signaling research. In *Science*, three Viewpoint articles reviewed our current knowledge of biochemical pathways involved in a broad range of biological processes from stem cell birth to programmed cell death. The articles were coupled with new additions to the freely accessible STKE Connections Maps database (http://stke.sciencemag.org/cm/). Each pathway map in the database is linked to relevant literature, citations, data, and background information, allowing users to explore how diverse pathways and their components relate to each other.
Tourette's syndrome (TS) is a potentially debilitating psychiatric disorder characterized by chronic vocal and motor tics. Although considerable evidence has suggested that genetic factors are involved in the syndrome, no susceptibility genes have been implicated . . . until now. In a study reported in the 14 Oct 2005 *Science*, Abelson et al. (http://www.sciencemag.org/cgi/content/short/310/5746/317) found that a small number of TS patients carry mutations in a gene called *SLITRK1* (short for * Slit and Trk-like family member 1*), which is related to a group of genes known to be involved in neuronal growth, guidance, and branching. Interestingly, the location of one of the mutations the team identified suggests that *SLITRK1* is regulated by microRNAs, an enigmatic class of small RNA molecules. Further study of this candidate gene and its protein product may shed more light on the cellular and molecular underpinnings of Tourette's. An accompanying News story by S. Olson (http://www.sciencemag.org/cgi/content/short/310/5746/211a) highlighted the Report.
Appetite, Weight Loss, and the Brain
The neural signals that help regulate appetite and energy balance converge in the brain's hypothalamus. Two Reports in the 28 Oct 2005 *Science* underscored the emerging idea that these feeding circuits are not firmly "hardwired" but rather exhibit remarkable plasticity. Luquet et al. (http://www.sciencemag.org/cgi/content/short/310/5748/683) showed that specific neurons required for regulating food intake in adult mice can be removed without harm in newborn mice, presumably because some compensatory mechanism takes over. Removal of these neurons in adults, on the other hand, results in rapid starvation, suggesting that the feeding circuitry can readily adapt to change only early in life.
In another study, Kokoeva et al. (http://www.sciencemag.org/cgi/content/short/310/5748/679) showed that the production of new neurons in the adult hypothalamus may be tied to the regulation of body weight. The researchers found that a growth factor that induces sustained weight loss in adult mice also stimulates growth of new neurons in the hypothalamus. Pharmacological inhibition of this neural growth compromised the capacity of the growth factor to induce long-term weight loss. These results indicate that hypothalamic plasticity may add another layer of complexity to the regulation of body weight. An accompanying News story by G. Vogel (http://www.sciencemag.org/cgi/content/short/310/5748/602a) highlighted the report.
Over the past decade, satellite technologies have enabled marine biologists to follow the oceanic travels of animals tagged with electronic transmitters. Now, two studies reported in the 7 Oct 2005 *Science* have used remote-sensing techniques to document the unexpected travels of the great white shark and its less fearsome cousin, the salmon shark. Bonfil et al. (http://www.sciencemag.org/cgi/content/short/310/5745/100) found that great whites are capable of fast transoceanic migrations in excess of 10,000 kilometers from South Africa to Australia , and back. These sharks also undertake regular migrations along the South African coast and make smaller-scale patrolling trips. In a separate study, Weng et al. (http://www.sciencemag.org/cgi/content/short/310/5745/104) discovered that salmon sharks are also long-distance travelers. The team tracked 48 satellite-tagged sharks based in Prince William Sound , Alaska and found that after wintering there, some animals headed south, sometimes going as far as Hawaii or Baja California before returning to Alaska . As with the great whites, the salmon sharks took multiple trips but always seemed to return to familiar territory. As noted in an accompanying News story by E. Pennisi (http://www.sciencemag.org/cgi/content/short/310/5745/32a), the unexpectedly large ranges for both sharks have a downside: "The more spread out a species is, the harder it is to protect."
Sustaining Mangroves and Aquaculture
Mangroves -- the lushly forested buffer zones between land and sea -- have contributed appreciably to the livelihood and well being of coastal communities throughout the Philippine islands. But as with land-based agriculture, increased aquatic food production has resulted in serious environmental problems ranging from habitat modification to erosion. Loss of mangroves has contributed to loss of the natural benefits they afford, including coastal protection, sediment trapping, and recycling of nutrients from terrestrial run-off and river discharges. In this month's Global Voices of Science essay (7 Oct 2005; http://www.sciencemag.org/cgi/content/short/310/5745/57), Dr. Jurgenne Primavera, senior scientist in the Aquaculture Department of the Southeast Asian Fisheries Development Centre in the central Philippines, discussed what steps might be taken to help preserve mangrove ecosystems and move the aquaculture industry toward the goal of sustainability. An online slideshow (http://www.sciencemag.org/sciext/globalvoices/) accompanied the essay.
Since its emergence in 2002, researchers have been searching for the origin of the severe acute respiratory syndrome (SARS) virus. In a Report in the 28 Oct 2005 *Science* (published online 29 Sep), Li et al. (http://www.sciencemag.org/cgi/content/short/310/5748/676) identified bats living in China as natural reservoir of coronaviruses closely related to those responsible for the SARS outbreak (see the News Focus by D. Normile in the 30 Sep 2005 issue; http://www.sciencemag.org/cgi/content/short/309/5744/2154). The team focused its efforts on samples from more than 400 bats representing nine species in several different bat genera and families, and discovered that some species of horseshoe bat harbored genetically diverse SARS-related coronaviruses. Bats are now known to be natural reservoir hosts to several other disease pathogens, including the Nipah and Hendra viruses, which have recently emerged in Australia and East Asia , respectively. As noted in an accompanying Perspective by A. P. Dobson (http://www.sciencemag.org/cgi/content/short/310/5748/628), knowing more about bat ecology and immunology is therefore crucial to controlling spillover of viruses and related diseases to humans.
In a Report in the 14 Oct 2005 *Science*, Nussey et al. (http://www.sciencemag.org/cgi/content/short/310/5746/304) studied how a Dutch population of birds called great tits have dealt with a gradual warming trend that began in the area in the 1980s. Female great tits typically time reproduction so that their chicks hatch at a time when caterpillars, their primary food source, are most plentiful. However, the warming trend has prompted earlier springs and earlier emergence of caterpillars. Although most birds have not changed their breeding schedule accordingly and are suffering declining offspring survival as a result, the researchers found that some climate-attuned birds have cleverly coped with the change. Some females have altered their behavior in accordance with the climate and peak caterpillar abundance, laying eggs earlier in the warm years and later in the cool years. Interestingly, this flexibility runs in families and confers a selective advantage: The climate-attuned females have twice as many surviving offspring. As noted in an accompanying News story by E. Pennisi (http://www.sciencemag.org/cgi/content/short/310/5746/215a), selection of this trait over time will likely eventually lead to a population that is better able to respond to climate change.
Because of the heavy concentration of the world's population along coastlines, even small amounts of sea-level rise associated with global warming could have tremendous societal and economic impacts. Complete melting of the Greenland and Antarctic ice sheets could raise sea level by some 70 meters, but uncertainties about ice sheet dynamics and the influence of freshwater fluxes and ocean circulation has hindered accurate projections of sea-level change. In a Review article in the 21 Oct 2005 *Science*, Alley et al. (http://www.sciencemag.org/cgi/content/short/310/5747/456) highlighted recent observational and modeling advances in the understanding of ice-sheet behavior. Recently detected, rapid changes at the sheets' margins may indicate that ice sheets may be more sensitive to warming than previously considered. Models are just beginning to include these dynamic responses, but if they prove to be important, projections of sea level rise may need to be revised upward.
In a related Report published online *Science* Express on 20 Oct 2005 , Johannessen et al. (http://www.sciencemag.org/cgi/content/abstract/1115356) offered insight into the behavior of the interior of the Greenland ice sheet. Satellite observations from 1992 to 2003 show that the ice sheet is thickening by an average of about centimeters per year, driven mostly by increased snow accumulation. This effect will be important to consider in future predictions of changes in ice sheet mass balance.
The extent of sea ice cover in the Arctic Ocean is now at its lowest level in more than a century, and many scientists believe that an ice-free Arctic Ocean could become a reality well before the century is up. News about the nearby continents is alarming as well. In a Report in the 28 Oct 2005 *Science*, Chapin et al. (http://www.sciencemag.org/cgi/content/short/310/5748/657) presented evidence that warming on the landmasses of the Arctic may also be accelerating. Field data from arctic Alaska show that changes in summer albedo -- the reflectivity of the surface to sunlight -- contribute substantially to the warming trends. Atmospheric warming has caused longer snow-free seasons in the Arctic . And because there is less snow cover to reflect sunlight, solar radiation is increasingly being absorbed by darker shrubs, trees, and soil, heating up the ground and the air above. These changes are contributing as much to Arctic warming as rising greenhouse gas levels and have the potential to amplify surface temperature two to seven times. As noted in an accompanying Perspective by J. A. Foley (http://www.sciencemag.org/cgi/content/short/310/5748/627), these results will need to be more fully incorporated into models of future climate change.
The atmosphere of Titan, Saturn's largest moon, is rich in methane that condenses to form clouds. Two Reports in the 21 Oct 2005 *Science* presented new observations from telescopes on the ground and on the Cassini spacecraft that reveal some of the dynamics of these clouds and provide insights on possible sources of methane. Griffith et al. (http://www.sciencemag.org/cgi/content/short/310/5747/474) analyzed data from Cassini, which show that Titan's clouds are dynamic yet short lived, popping up in midlatitudes within 30 minutes and then dissipating as rain over the next several hours as they waft downwind. Interestingly, Roe et al. (http://www.sciencemag.org/cgi/content/short/310/5747/477) described observations from the Keck and Gemini telescopes in Hawaii which show that for several months, these clouds tended to cluster in one region in the southern hemisphere of Titan. The clouds' localized abundance cannot be explained by a seasonal shift in global circulation and therefore more likely reflects something special about the surface beneath them. As noted in an accompanying News story by R. A. Kerr (http://www.sciencemag.org/cgi/content/short/310/5747/421a), both sets of results may be consistent with the existence of geysers or icy volcanoes that provide a local source of methane on this part of Titan.
Anthropoids -- a large group of extant and fossil primates that includes monkeys, apes, and humans -- arose about 45 to 55 million years ago (Ma) in Africa or Asia , but much of their history prior to about 35 Ma is poorly understood. In a Report in the 14 Oct 2005 *Science*, Seiffert et al. (http://www.sciencemag.org/cgi/content/short/310/5746/300) described the earliest and most complete African anthropoid fossils from the Fayum desert region of Egypt. The fossils are about 37 million years old and consist of small teeth and jawbones from two tiny monkey-like creatures of the genus *Biretia*. Interestingly, one of the creatures appears to have been nocturnal, the first example of a nocturnal early anthropoid. The fossil teeth share some key features with African fossils more than 45 million years old and with other, much younger anthropoids, drawing all of these taxa into a diverse group with surprising antiquity. The team's phylogenetic analysis is also consistent with the view that African anthropoids immigrated from Asia at a very early date, probably before the late Paleocene (60 Ma). However, it is also possible that there were several waves of Asian immigrations. As noted in an accompanying Perspective by J.-J. Jaeger and L. Marivaux (http://www.sciencemag.org/cgi/content/short/310/5746/244), a more complete fossil record will be needed to bridge the remaining gaps in our understanding of anthropoid history.
Progress in rational chemical synthesis has fostered the miniaturization of macroscopic engineering components, such as gears and springs, to the molecular scale. In a Report in the 7 Oct 2005 *Science*, Fletcher et al. (http://www.sciencemag.org/cgi/content/short/310/5745/80) described the synthesis of another component important for the realization of nanoscale machines -- a molecular rotor capable of specific directed rotation. The researchers showed that a sequence of chemical reactions can induce a compound to rotate fully around a carbon-carbon single bond. A cycle consisting of two bond-breaking steps and two bond-forming steps controls the movement of the molecular rotor through four structurally distinct "stations", effectively mimicking the action of a turnstile. Furthermore, the choice of reagents determines whether rotation about the carbon-carbon single bond axis is clockwise or counterclockwise. An accompanying Perspective by J. Siegel (http://www.sciencemag.org/cgi/content/short/310/5745/63) discussed the new work in the broader context of approaches to molecular engineering.
At room temperature, metals and insulators usually represent very different classes of materials, but a number of materials systems can undergo metal-to-insulator transitions at low temperatures. In a study reported in the 21 Oct 2005 *Science* Wachowiak et al. (http://www.sciencemag.org/cgi/content/short/310/5747/468) used scanning tunneling microscopy to observe the molecular distortions that occur during the metal-to-insulator transition in a thin film of potassium-containing C60 fullerenes -- hollow soccerball-shaped structures composed of 60 carbon atoms. The team found that increasing the potassium-to-C60 ratio from 3 to 4 leads to a charge-induced structural rearrangement of the molecules that converts the film from metallic to insulating. C60 fullerenes are ideal building blocks for molecular devices because electrons can easily be donated to the inside of the molecule, thereby changing its molecular electronic properties. Combined with theoretical calculations, the new work offers a detailed view of just how these properties change in the context of a molecular nanostructure. An accompanying Perspective by J. N. O'Shea (http://www.sciencemag.org/cgi/content/short/310/5747/453) highlighted the Report.
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’Tis the Season to Give the Gift of Science
Give a membership to the largest general science society in the world - AAAS. Your gift includes 51 issues of the weekly journal Science and online access to Science archives, new research, career information, discounts on books, and more. As our thank you, you’ll receive our popular 125th Science Anniversary shirt. For details and to order, go to promo.aaas.org/gift7