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  • TRCF | Newswire
    Transcription Repair Coupling Factor or TRCF that plays a dual role in DNA transcription repair The results show that TRCF employs a modular structure which would allow for conformational changes so that TRCF s recruitment of the repair machinery doesn t interfere with its interruption of transcription More Tags DNA repair Seth Darst transcription factors TRCF Search for Categories Science News Awards and Honors Campus News Grants Gifts Topics Video

    Original URL path: http://newswire.rockefeller.edu/tag/trcf/ (2016-02-13)
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  • Molecular image of genotoxin reveal how bacteria damage human DNA | Newswire
    into cell cycle arrest While some CDT invaded cells continue to grow in size without dividing others commit suicide through a process known as apoptosis These cellular reactions to CDT invasion are not surprising because cells have checkpoint mechanisms to insure that DNA sequences are copied correctly during the process of replication says Stebbins When a mistake or a break in DNA is detected cells either repair the DNA or if it is irreparable they stop replicating and often commit suicide This process is a protection mechanism to stop mistakes from being propagated Stebbins says that CDT containing bacteria might induce cell cycle arrest because it stops cells from being sloughed off in areas such as the intestines where bacteria seek to make a home CDT may also act as an immunosuppressant says Stebbins since the immune system requires cell division to respond to microbial infection There are nearly 10 different species of disease causing bacteria that use CDT including Salmonella typhi a bacteria that causes typhoid fever Haemophilus ducreyi a bacteria that causes genital ulcers Campylobacter jejuni a common cause of food poisoning certain strains of Escherichia coli that cause diarrhea and a host of other pathogenic bacteria More CDT containing bacteria are discovered each year says Stebbins Many of these bacteria cause very different kinds of diseases and colonize different tissues But they all have CDT To me that argues that it s playing an important role Stebbins structure of CDT visually confirms that this genotoxin is made up of three subunits including one called CdtB that cleaves or cuts DNA According to Stebbins model the three unit toxin contains a long deep groove a cluster of ring shaped molecules called the aromatic patch and a dangling protein tail that can block a key portion of the CdtB subunit that is necessary for DNA cleavage We re not sure what the role of the cleavage blocking protein tail is but the structure helps us to understand how to interact with the active site of CdtB to impair its activity which could give us some ideas for achieving the same thing with a drug molecule said Stebbins Armed with an atomic model of a protein scientists can program computers to screen virtual representations of millions of compounds to see if they have a good chance of interacting with the target Compounds are narrowed down to a selected few which are then tested to determine how well they interact with the drug target By screening compounds by computer before physically testing them drug makers save time and money Stebbins laboratory includes a drug design team which is currently designing molecules to thwart bioterrorism agents such as anthrax and plague In the future the lab might design a drug against the CDT toxin Stebbins says We can screen three million molecules against a particular target in two weeks by computer says Stebbins That s good for finding about 500 molecules that are potential drugs that can be examined for activity against

    Original URL path: http://newswire.rockefeller.edu/2004/05/29/molecular-image-of-genotoxin-reveal-how-bacteria-damage-human-dna/ (2016-02-13)
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  • C. Erec Stebbins | Newswire
    cell death and even communication between cells More Tags bacteria C Erec Stebbins December 3 2008 Science News Structure of a virulent pathogen revealed Certain mean strains of bacteria inject virulent teams of molecules into cells that prepare the way for bacteria to invade the cells and reproduce spreading disease Different types of these molecules called virulence factors wreak havoc in cells basic functioning in different ways Now using x ray crystallography researchers at The Rockefeller University have revealed the structure of one such molecule that has the especially damaging effect of arresting its host cells division The finding offers clues as to how this bacterial weapon works and potentially how to defend against it or even use it to attack cancer More Tags C Erec Stebbins E Coli September 3 2008 Science News C Erec Stebbins awarded prestigious EUREKA grant C Erec Stebbins associate professor at The Rockefeller University has been awarded an inaugural EUREKA grant from the National Institutes of Health for a project aimed at exploiting a bacteria based nanosyringe as a means of delivering proteins into specific cells for therapeutic purposes The award which provides 200 000 a year for three years was announced by the NIH September 3 More Tags C Erec Stebbins Eureka January 25 2008 Science News Structural study of anthrax yields new antibiotic target By describing the structure of an enzyme involved in building an essential piece of the bacterium s cell wall Rockefeller University researchers have found a promising new drug target for anthrax and other bacteria More Tags Anthrax C Erec Stebbins September 18 2006 Science News A wolf in sheep s clothing plague bacteria reveal one of their virulence tricks The bacteria known as Yersinia a family of pathogens that includes the plague kill their host cells by among other things inserting proteins and other virulence factors that disrupt their normal structure New research by Rockefeller University scientists shows at the atomic cellular and organismal level that the cause of this disruption can be attributed largely to YpkA a virulence factor that mimics proteins found in its host More Tags C Erec Stebbins plague yersinia August 16 2006 Science News Structural analysis of SpvB protein show how Salmonella bacteria hijack a cell Salmonella and related bacteria disable proteins that a cell uses to create its structural framework By solving the structure of Salmonella s SpvB virulence protein and the actin molecules it modifies Rockefeller University researchers show that the bacteria alter the cell s actin proteins to prevent them from stacking together into filaments More Tags C Erec Stebbins Salmonella SpvB March 10 2006 Science News Structural study shows how bacteria select their most virulent proteins A diverse group of bacteria all rely on the same syringe like system to infect their hosts Rockefeller researchers have now uncovered a structural similarity shared by many of these virulent pathogens that may help direct future antibiotic research More Tags C Erec Stebbins type III virulence factors December 23 2005 Science News

    Original URL path: http://newswire.rockefeller.edu/tag/c-erec-stebbins/ (2016-02-13)
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  • CDT | Newswire
    29 2004 Science News Molecular image of genotoxin reveal how bacteria damage human DNA The three dimensional structure of a DNA damaging bacterial toxin has been visualized by scientists at Rockefeller University The molecular image of the toxin published in the May 27 issue of the journal Nature shows exactly how the toxin is put together at the molecular level and damages human DNA The structure also could help scientists

    Original URL path: http://newswire.rockefeller.edu/tag/cdt/ (2016-02-13)
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  • First images of protein export in cells illuminate structural “highways” called microtubules as sole conduits of protein cargo | Newswire
    which cellular structures or roads serve to guide the protein cargo at the last stage of the journey before it arrives at the cell surface To once and for all solve this enduring riddle the Rockefeller researchers decided to take a novel approach they simply used their eyes Fine tuning a light microscopy technique called Total Internal Reflection Fluorescence Microscopy the scientists were able to literally watch protein cargo twist its way out of the cell along microtubule highways The findings came as a surprise because many previous experiments suggested that the protein cargo s journey only began along microtubules before being diverted to smaller streets called actin filaments We were not expecting the actin filaments to have zero involvement but that s the beauty of microscopic techniques they allow you to rule out working hypotheses says Simon Road out of town Once a protein is assembled inside a cell by tiny machines called ribosomes it must be exported to its proper destination so that it can carry out its assigned task For example some proteins work inside the cell in the nucleus or in other cellular compartments others such as ion channels and receptors perform their duties within the cellular membrane Still others such as neurotransmitters and hormones function outside of the cell These two latter groups of proteins the membrane and secretory proteins must therefore be transported to the cell s surface where they are then either assimilated into the membrane or expelled out of the cell To accomplish this task called exocytosis the cell begins by sending newborn proteins to an organelle called the endoplasmic reticulum Rockefeller Professor Günter Blobel M D Ph D was awarded the Nobel Prize in 1999 for his demonstration of the zip codes that target nascent proteins to this organelle Blobel together with Simon also showed that these zip codes act like keys to open water filled pores that allow the proteins to enter this compartment Once inside the endoplasmic reticulum protein exports are packaged into membrane bound vesicles which serve as personalized vehicles to transport the proteins to the surface George Palade Ph D an early pioneer in the field of cell biology at Rockefeller was awarded the Nobel Prize in 1974 for his characterization of the pathway these vesicles take from the endoplasmic reticulum to the surface where they finally dock with the membrane and release their contents But just how these protein filled vesicles make their way to the cellular surface has remained unclear While it is known that the vesicles are initially loaded onto the thick microtubules it is not obvious where their journey ends The most popular theory holds that microtubules make up the beginning of the trip while actin filaments form the end Both microtubules and actin filaments constitute part of a cell s cytoskeleton a dynamic structure consisting of long fibrous proteins that provide both structural support and the ability to move Shining light on the problem To address this issue from a new perspective

    Original URL path: http://newswire.rockefeller.edu/2003/04/11/first-images-of-protein-export-in-cells-illuminate-structural-highways-called-microtubules-as-sole-conduits-of-protein-cargo/ (2016-02-13)
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  • exocytosis | Newswire
    pathway followed by a protein as it exits the body cell that created it Once released from a cell a protein is free to perform its duties as a neurotransmitter hormone cell surface receptor or one of the many other work horses that function outside of body cells every second of the day More Tags exocytosis microtubules Sanford M Simon Search for Categories Science News Awards and Honors Campus News

    Original URL path: http://newswire.rockefeller.edu/tag/exocytosis/ (2016-02-13)
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  • Sanford M. Simon | Newswire
    the potential to help researchers develop new treatments for AIDS More Tags HIV Paul Bieniasz Sanford M Simon September 21 2007 Science News Viewing dye packed vesicles causes them to explode A fluorescent marker long used in imaging to help researchers watch membrane bound vesicles as they exit a cell can actually cause the vesicles to break open as soon as they re hit with light from a microscope New research describes how to differentiate a microscopy side effect from the cell s true process More Tags Sanford M Simon vesicles June 20 2003 Science News Cellular transport vehicles caught on film They look like soccer balls only much smaller They are tiny transport vehicles used by cells to import biological cargo and for the first time Rockefeller University researchers have caught them on film swimming across the surface of cells More Tags clathrin clathrin pits Sanford M Simon April 11 2003 Science News First images of protein export in cells illuminate structural highways called microtubules as sole conduits of protein cargo For the first time scientists have viewed and recorded on camera the final pathway followed by a protein as it exits the body cell that created it Once released from a cell a protein is free to perform its duties as a neurotransmitter hormone cell surface receptor or one of the many other work horses that function outside of body cells every second of the day More Tags exocytosis microtubules Sanford M Simon December 13 2002 Science News Observing Proteins and Cells in the Wild Imagine if molecular and cell biologists could watch proteins and cells at work in their natural habitat in the same way that wildlife biologists observe animals in the wild They d sit back and witness firsthand their microscopic subjects daily routines interactions and

    Original URL path: http://newswire.rockefeller.edu/tag/sanford-m-simon/ (2016-02-13)
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  • Rockefeller researchers identify new mechanism that ensures accurate partitioning of genetic material in dividing cells | Newswire
    Rockefeller researchers have shown that the minus ends of microtubules provide a mechanism along with a previously identified complementary mechanism mediated by the plus ends for aligning and segregating chromosomes in the dividing cell Microtubules have polarity a plus and a minus end which results from the asymmetric assembly of the tubulin molecules that compose the microtubules In mitosis the minus ends of microtubules are usually associated with the centrosome and the plus ends are associated with kinetochores the plate like structures on the duplicated chromosomes where microtubules attach Research by other scientists during the last 20 years has produced a textbook model called search and capture in which the plus ends of the microtubules capture the duplicated chromosomes The new research by Kapoor and Copenagle reveals that the minus ends previously considered to be static and undynamic are actually very dynamic and provide a complementary mechanism for aligning and segregating chromosomes in the dividing cell We needed to perturb the dividing cell in order to observe this minus end capture mechanism says Kapoor But now that we know what it looks like we see it happening in normally dividing cells To perturb the dividing cell Kapoor and Copenagle used a small molecule inhibitor called monastrol While at Harvard Medical School Kapoor and colleagues found that monastrol blocks the function of a key microtubule motor protein called Eg5 which is necessary for forming a bipolar spindle Scientists hypothesize that Eg5 helps to separate the poles of the spindle When dividing cells are exposed to monastrol Eg5 is inactive and the spindle poles collapse forming a monopolar spindle where both centrosomes lie in the center of an aster of microtubules Removing monastrol results in a rapid reversal of this affect and the spindle reverts to its usual bipolar configuration The general question we wanted to answer was what happens if a chromosome is poorly oriented such that its kinetochore cannot encounter the microtubules emanating from the centrosomes says Copenagle To answer this question the researchers combined the powerful tools of small molecule inhibitors and live cell microscopy By using monastrol we wanted to increase the probability of finding a chromosome that is not correctly attached that is a chromosome with an attachment to only one pole says Copenagle Using a spinning disk confocal microscope which can image the dynamics of fluorescent proteins and chromosomes in a cell in real time Kapoor and Copenagle observed dividing cells under the influence of monastrol Real time imaging of the cells was done in collaboration with Rockefeller s Bio Imaging Resource Center directed by Alison North The spinning disk confocal microscope produces the highest resolution images of a cell we have seen Kapoor says We can watch how a single chromosome in a vertebrate cell attaches itself to the mitotic apparatus What they found was surprising microtubules extended away from mono oriented kinetochores out into the cytoplasm and looped back toward the spindle We believe this looping and capture of microtubules occurs when the unattached

    Original URL path: http://newswire.rockefeller.edu/2003/03/10/rockefeller-researchers-identify-new-mechanism-that-ensures-accurate-partitioning-of-genetic-material-in-dividing-cells/ (2016-02-13)
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