225 research outputs found
A dynamic mode of mitotic bookmarking by transcription factors.
During mitosis, transcription is shut off, chromatin condenses, and most transcription factors (TFs) are reported to be excluded from chromosomes. How do daughter cells re-establish the original transcription program? Recent discoveries that a select set of TFs remain bound on mitotic chromosomes suggest a potential mechanism for maintaining transcriptional programs through the cell cycle termed mitotic bookmarking. Here we report instead that many TFs remain associated with chromosomes in mouse embryonic stem cells, and that the exclusion previously described is largely a fixation artifact. In particular, most TFs we tested are significantly enriched on mitotic chromosomes. Studies with Sox2 reveal that this mitotic interaction is more dynamic than in interphase and is facilitated by both DNA binding and nuclear import. Furthermore, this dynamic mode results from lack of transcriptional activation rather than decreased accessibility of underlying DNA sequences in mitosis. The nature of the cross-linking artifact prompts careful re-examination of the role of TFs in mitotic bookmarking
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A stable mode of bookmarking by TBP recruits RNA polymerase II to mitotic chromosomes.
Maintenance of transcription programs is challenged during mitosis when chromatin becomes condensed and transcription is silenced. How do the daughter cells re-establish the original transcription program? Here, we report that the TATA-binding protein (TBP), a key component of the core transcriptional machinery, remains bound globally to active promoters in mouse embryonic stem cells during mitosis. Using live-cell single-molecule imaging, we observed that TBP mitotic binding is highly stable, with an average residence time of minutes, in stark contrast to typical TFs with residence times of seconds. To test the functional effect of mitotic TBP binding, we used a drug-inducible degron system and found that TBP promotes the association of RNA Polymerase II with mitotic chromosomes, and facilitates transcriptional reactivation following mitosis. These results suggest that the core transcriptional machinery promotes efficient transcription maintenance globally
Wanted: standards for automatic reproducibility of computational experiments
Those seeking to reproduce a computational experiment often need to manually
look at the code to see how to build necessary libraries, configure parameters,
find data, and invoke the experiment; it is not automatic. Automatic
reproducibility is a more stringent goal, but working towards it would benefit
the community. This work discusses a machine-readable language for specifying
how to execute a computational experiment. We invite interested stakeholders to
discuss this language at https://github.com/charmoniumQ/execution-description .Comment: Submitted to SE4RS'23 Portland, O
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Evidence for DNA-mediated nuclear compartmentalization distinct from phase separation.
RNA Polymerase II (Pol II) and transcription factors form concentrated hubs in cells via multivalent protein-protein interactions, often mediated by proteins with intrinsically disordered regions. During Herpes Simplex Virus infection, viral replication compartments (RCs) efficiently enrich host Pol II into membraneless domains, reminiscent of liquid-liquid phase separation. Despite sharing several properties with phase-separated condensates, we show that RCs operate via a distinct mechanism wherein unrestricted nonspecific protein-DNA interactions efficiently outcompete host chromatin, profoundly influencing the way DNA-binding proteins explore RCs. We find that the viral genome remains largely nucleosome-free, and this increase in accessibility allows Pol II and other DNA-binding proteins to repeatedly visit nearby DNA binding sites. This anisotropic behavior creates local accumulations of protein factors despite their unrestricted diffusion across RC boundaries. Our results reveal underappreciated consequences of nonspecific DNA binding in shaping gene activity, and suggest additional roles for chromatin in modulating nuclear function and organization
Efectividad de clorogenos destinados a agua de consumo
Se propone una metodología para la evaluación de productos clorógenos destinados a la desinfección de aguas paraconsumo, utilizando materia orgánica para simular el consumo de cloro que tienen las aguas no tratadas. Se evaluóel comportamiento de suspensión de levadura de cerveza, peptona y extracto de levadura frente a dosis usuales (10mg/L, como cloro total) de comprimidos de la sal disódica de la dicloro-S-triazina-triona. Como comparación seutilizó agua de río.Se determinó la concentración de cada sustancia orgánica que despues de 30 minutos dejó 0,1 mg/L de cloro libreen la solución de ensayo. Posteriormente se ensayó microbiologicamente la efectividad del clorógeno en presencia dedichas sustancias según metodología AFNOR
147 Description of Burkholderia contaminans isolates recovered from sputum of cystic fibrosis (CF) patients with different courses of infection
Barriers to Therapeutic Regimen Adherence of Type II Diabetes Mellitus Patients in Iligan City, Philippines
The purpose of this study is to explore the barriers that have an impact on the adherence to therapeutic regimen among Type II diabetics in Iligan City. Specifically, it attempted to evaluate if there's a significant relationship among the patients' length of diagnosis, blood sugar level, awareness of the disease,their relationship towards their doctors and the availability and accessibility to healthcare services as to their adherence to therapeutic regimen in terms of their medication, diet, exercise, lifestyle and stress reduction techniques. It also tried to examine if the patients' profiles (age, gender, religion, civil status,educational attainment, work status, family monthly income, social support system and clinic) can influence their therapeutic regimen adherence. This study used the Descriptive Survey Method. 10 self-structured questionnaires derived from published questionnaires were given to 56 Type II diagnosed diabetes mellitus patients in the private and public clinics of Iligan City, selected through random sampling technique. Data generated by the questionnaires were analyzed using descriptive statistics and correlations. Results from thesurvey showed that the patients' accessibility to healthcare services and their social support system largely affect their medication adherence. Female and working patients are more diligent in taking their medication. Patients having their consultation in the public clinic and those with lower blood glucose level prove to have a better performance in lifestyle modification. Patients who are married, working, and who are more aware about their disease showed to be more effective in reducing stress than the other patients. Patients in thepublic clinic exercise more than those in the private clinics. Finally, the frequency in which the patients were doing exercise is greatly affected on how efficient their healthcare providers ar
50 años de Antropología en el Museo de Ciencias Naturales de La Plata: historia, desafíos y perspectivas
Recientemente y en diferentes contextos, los antropólogos argentinos comenzaron a discutir acerca del perfil profesional. La formación universitaria, las demandas e inserción en diversos sectores sociales fueron conciliados para definir nuevas perspectivas en el desarrollo disciplinar. La Carrera de Antropología se inicia en el Museo de Ciencias Naturales de La Plata en 1958, con una orientación teórica definida en el marco de las Ciencias Naturales. Ello ha aportado interesantes enfoques que posibilitan la intervención del antropólogo en proyectos y programas interdisciplinarios. El presente trabajo intenta dar cuenta del proceso de revisión de nuestra historia institucional. Esperamos contribuir a la consolidación de espacios formales de discusión y organización para superar la fragmentación que aún se advierte pese a los cincuenta años transcurridos de la creación de las carreras de Antropología en nuestro país.Recently and in different contexts, the Argentine anthropologists began to discuss professional profile. The University education, the demands and insertion in various social sectors were agree to define new perspectives in development discipline. Anthropology as a course of studies starts at the Museum of Silver Natural Sciences in 1958 with a defined theoretical orientation in the framework of natural sciences. This has yielded interesting approaches to enable the intervention of the anthropologist in projects and programmes interdisciplinary. The present paper attempts to give an account of the process revision of our institutional history. We hope will contribute to the consolidation of formal spaces for discussion and organization to overcome the fragmentation that are still warned despite the 50 years of the creation of anthropology course of studies in our country.Facultad de Ciencias Naturales y Muse
Quantum Dissipative Effects and Neutrinos : current constraints and future perspectives
We establish the most stringent experimental constraints coming from recent
terrestrial neutrino experiments on quantum mechanical decoherence effects in
neutrino systems. Taking a completely phenomenological approach, we probe
vacuum oscillations plus quantum decoherence between two neutrino species in
the channels , and , admitting that the quantum decoherence parameter is related
to the neutrino energy as : ,
with and 2. Our bounds are valid for a neutrino mass squared
difference compatible with the atmospheric, the solar and, in many cases, the
LSND scale. We also qualitatively discuss the perspectives of the future long
baseline neutrino experiments to further probe quantum dissipation.Comment: 26 pages, 8 encapsulated postscript figure
Discriminating among Earth composition models using geo-antineutrinos
It has been estimated that the entire Earth generates heat corresponding to
about 40 TW (equivalent to 10,000 nuclear power plants) which is considered to
originate mainly from the radioactive decay of elements like U, Th and K,
deposited in the crust and mantle of the Earth. Radioactivity of these elements
produce not only heat but also antineutrinos (called geo-antineutrinos) which
can be observed by terrestrial detectors. We investigate the possibility of
discriminating among Earth composition models predicting different total
radiogenic heat generation, by observing such geo-antineutrinos at Kamioka and
Gran Sasso, assuming KamLAND and Borexino (type) detectors, respectively, at
these places. By simulating the future geo-antineutrino data as well as reactor
antineutrino background contributions, we try to establish to which extent we
can discriminate among Earth composition models for given exposures (in units
of kt yr) at these two sites on our planet. We use also information on
neutrino mixing parameters coming from solar neutrino data as well as KamLAND
reactor antineutrino data, in order to estimate the number of geo-antineutrino
induced events.Comment: 24 pages, 10 figures, final version to appear in JHE
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