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Found 37173 matches. Displaying 3971-3980
Milosevic A, Liebmann T, Knudsen M, Schintu N, Svenningsson P, Greengard P
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Cell- and region-specific expression of depression-related protein p11 (S100a10) in the brain

JOURNAL OF COMPARATIVE NEUROLOGY 2017 MAR 1; 525(4):955-975
P11 (S100a10), a member of the S100 family of proteins, has widespread distribution in the vertebrate body, including in the brain, where it has a key role in membrane trafficking, vesicle secretion, and endocytosis. Recently, our laboratory has shown that a constitutive knockout of p11 (p11-KO) in mice results in a depressive-like phenotype. Furthermore, p11 has been implicated in major depressive disorder (MDD) and in the actions of antidepressants. Since depression affects multiple brain regions, and the role of p11 has only been determined in a few of these areas, a detailed analysis of p11 expression in the brain is warranted. Here we demonstrate that, although widespread in the brain, p11 expression is restricted to distinct regions, and specific neuronal and nonneuronal cell types. Furthermore, we provide comprehensive mapping of p11 expression using in situ hybridization, immunocytochemistry, and whole-tissue volume imaging. Overall, expression spans multiple brain regions, structures, and cell types, suggesting a complex role of p11 in depression. J. Comp. Neurol. 525:955-975, 2017. (c) 2016 Wiley Periodicals, Inc.
Gleicher N, Orvieto R
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Is the hypothesis of preimplantation genetic screening (PGS) still supportable? A review

JOURNAL OF OVARIAN RESEARCH 2017 MAR 27; 10(?):? Article 21
The hypothesis of preimplantation genetic diagnosis (PGS) was first proposed 20 years ago, suggesting that elimination of aneuploid embryos prior to transfer will improve implantation rates of remaining embryos during in vitro fertilization (IVF), increase pregnancy and live birth rates and reduce miscarriages. The aforementioned improved outcome was based on 5 essential assumptions: (i) Most IVF cycles fail because of aneuploid embryos. (ii) Their elimination prior to embryo transfer will improve IVF outcomes. (iii) A single trophectoderm biopsy (TEB) at blastocyst stage is representative of the whole TE. (iv) TE ploidy reliably represents the inner cell mass (ICM). (v) Ploidy does not change (i. e., self-correct) downstream from blastocyst stage. We aim to offer a review of the aforementioned assumptions and challenge the general hypothesis of PGS. We reviewed 455 publications, which as of January 20, 2017 were listed in PubMed under the search phrase < preimplantation genetic screening (PGS) for aneuploidy>. The literature review was performed by both authors who agreed on the final 55 references. Various reports over the last 18 months have raised significant questions not only about the basic clinical utility of PGS but the biological underpinnings of the hypothesis, the technical ability of a single trophectoderm (TE) biopsy to accurately assess an embryo's ploidy, and suggested that PGS actually negatively affects IVF outcomes while not affecting miscarriage rates. Moreover, due to high rates of false positive diagnoses as a consequence of high mosaicism rates in TE, PGS leads to the discarding of large numbers of normal embryos with potential for normal euploid pregnancies if transferred rather than disposed of. We found all 5 basic assumptions underlying the hypothesis of PGS to be unsupported: (i) The association of embryo aneuploidy with IVF failure has to be reevaluated in view how much more common TE mosaicism is than has until recently been appreciated. (ii) Reliable elimination of presumed aneuploid embryos prior to embryo transfer appears unrealistic. (iii) Mathematical models demonstrate that a single TEB cannot provide reliable information about the whole TE. (iv) TE does not reliably reflect the ICM. (v) Embryos, likely, still have strong innate ability to self0-correct downstream from blastocyst stage, with ICM doing so better than TE. The hypothesis of PGS, therefore, no longer appears supportable. With all 5 basic assumptions underlying the hypothesis of PGS demonstrated to have been mistaken, the hypothesis of PGS, itself, appears to be discredited. Clinical use of PGS for the purpose of IVF outcome improvements should, therefore, going forward be restricted to research studies.
Campbell EA, Kamath S, Rajashankar KR, Wu MY, Darst SA
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Crystal structure of Aquifex aeolicus sigma(N) bound to promoter DNA and the structure of sigma(N)-holoenzyme

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 2017 MAR 7; 114(10):E1805-E1814
The bacterial sigma factors confer promoter specificity to the RNA polymerase (RNAP). One alternative sigma factor, sigma(N), is unique in its structure and functional mechanism, forming transcriptionally inactive promoter complexes that require activation by specialized AAA(+) ATPases. We report a 3.4- angstrom resolution X-ray crystal structure of a sigma(N) fragment in complex with its cognate promoter DNA, revealing the molecular details of promoter recognition by sigma(N). The structure allowed us to build and refine an improved sigma(N)-holoenzyme model based on previously published 3.8-angstrom resolution X-ray data. The improved sigma(N)-holoenzyme model reveals a conserved interdomain interface within sigma(N) that, when disrupted by mutations, leads to transcription activity without activator intervention (so-called bypass mutants). Thus, the structure and stability of this interdomain interface are crucial for the role of sigma(N) in blocking transcription activity and in maintaining the activator sensitivity of sigma(N).
Lardelli RM, Schaffer AE, Eggens VRC, Zaki MS, Grainger S, Sathe S, Van Nostrand EL, Schlachetzki Z, Rosti B, Akizu N, Scott E, Silhavy JL, Heckman LD, Rosti RO, Dikoglu E, Gregor A, Guemez-Gamboa A, Musaev D, Mande R, Widjaja A, Shaw TL, Markmiller S, Marin-Valencia I, Davies JH, de Meirleir L, Kayserili H, Altunoglu U, Freckmann ML, Warwick L, Chitayat D, Blaser S, Caglayan AO, Bilguvar K, Per H, Fagerberg C, Christesen HT, Kibaek M, Aldinger KA, Manchester D, Matsumoto N, Muramatsu K, Saitsu H, Shiina M, Ogata K, Foulds N, Dobyns WB, Chi NC, Traver D, Spaccini L, Bova SM, Gabrie SB, Gunel M, Valente EM, Nassogne MC, Bennett EJ, Yeo GW, Baas F, Lykke-Andersen J, Gleeson JG
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Biallelic mutations in the 3 ' exonuclease TOE1 cause pontocerebellar hypoplasia and uncover a role in snRNA processing

NATURE GENETICS 2017 MAR; 49(3):457-464
Deadenylases are best known for degrading the poly(A) tail during mRNA decay. The deadenylase family has expanded throughout evolution and, in mammals, consists of 12 Mg2+-dependent 3'-end RNases with substrate specificity that is mostly unknowns. Pontocerebellar hypoplasia type 7 (PCH7) is a unique recessive syndrome characterized by neurodegeneration and ambiguous genitalia(2). We studied 12 human families with PCH7, uncovering biallelic, loss-of-function mutations in TOE1, which encodes an unconventional deadenylase(3,4). toe1-morphant zebrafish displayed midbrain and hindbrain degeneration, modeling PCH-like structural defects in vivo. Surprisingly, we found that TOE1 associated with small nuclear RNAs (snRNAs) incompletely processed spliceosomal. These pre-snRNAs contained 3' genome-encoded tails often followed by post-transcriptionally added adenosines. Human cells with reduced levels of TOE1 accumulated 3'-end-extended pre-snRNAs, and the immunoisolated TOE1 complex was sufficient for 3'-end maturation of snRNAs. Our findings identify the cause of a neurodegenerative syndrome linked to snRNA maturation and uncover a key factor involved in the processing of snRNA 3' ends.
Azimzadeh JB, Salvi JD
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Physiological Preparation of Hair Cells from the Sacculus of the American Bullfrog (Rana catesbeiana)

JOVE-JOURNAL OF VISUALIZED EXPERIMENTS 2017 MAR; ?(121):? Article e55380
The study of hearing and balance rests upon insights drawn from biophysical studies of model systems. One such model, the sacculus of the American bullfrog, has become a mainstay of auditory and vestibular research. Studies of this organ have revealed how sensory cells hair can actively detect signals from the environment. Because of these studies, we now better understand the mechanical gating and localization of a hair cell's transduction channels, calcium's role in mechanical adaptation, and the identity of hair cell currents. This highly accessible organ continues to provide insight into the workings of hair cells. Here we describe the preparation of the bullfrog's sacculus for biophysical studies on its hair cells. We include the complete dissection procedure and provide specific protocols for the preparation of the sacculus in specific contexts. We additionally include representative results using this preparation, including the calculation of a hair bundle's instantaneous force-displacement relation and measurement of a bundle's spontaneous oscillation.
Jin JJ, Sun YW, Qu J, Syah R, Lim CH, Alfiko Y, Rahman N, Suwanto A, Yue GH, Wong L, Chua NH, Ye J
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Transcriptome and functional analysis reveals hybrid vigor for oil biosynthesis in oil palm

SCIENTIFIC REPORTS 2017 MAR 27; 7(?):? Article 439
Oil palm is the most productive oil crop in the world and composes 36% of the world production. However, the molecular mechanisms of hybrids vigor (or heterosis) between Dura, Pisifera and their hybrid progeny Tenera has not yet been well understood. Here we compared the temporal and spatial compositions of lipids and transcriptomes for two oil yielding organs mesocarp and endosperm from Dura, Pisifera and Tenera. Multiple lipid biosynthesis pathways are highly enriched in all non-additive expression pattern in endosperm, while cytokinine biosynthesis and cell cycle pathways are highly enriched both in endosperm and mesocarp. Compared with parental palms, the high oil content in Tenera was associated with much higher transcript levels of EgWRI1, homolog of Arabidopsis thaliana WRINKLED1. Among 338 identified genes in lipid synthesis, 207 (61%) has been identified to contain the WRI1 specific binding AW motif. We further functionally identified EgWRI1-1, one of three EgWRI1 orthologs, by genetic complementation of the Arabidopsis wri1 mutant. Ectopic expression of EgWRI1-1 in plant produced dramatically increased seed mass and oil content, with oil profile changed. Our findings provide an explanation for EgWRI1 as an important gene contributing hybrid vigor in lipid biosynthesis in oil palm.
Wan LL, Wen H, Li YY, Lyu J, Xi YX, Hoshii T, Joseph JK, Wang XL, Loh YHE, Erb MA, Souza AL, Bradner JE, Shen L, Li W, Li HT, Allis CD, Armstrong SA, Shi XB
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ENL links histone acetylation to oncogenic gene expression in acute myeloid leukaemia

NATURE 2017 MAR 9; 543(7644):265-269
Cancer cells are characterized by aberrant epigenetic landscapes and often exploit chromatin machinery to activate oncogenic gene expression programs(1). Recognition of modified histones by 'reader' proteins constitutes a key mechanism underlying these processes; therefore, targeting such pathways holds clinical promise, as exemplified by the development of bromodomain and extra-terminal (BET) inhibitors(2,3). We recently identified the YEATS domain as an acetyl-lysine-binding module(4), but its functional importance in human cancer remains unknown. Here we show that the YEATS domain-containing protein ENL, but not its paralogue AF9, is required for disease maintenance in acute myeloid leukaemia. CRISPR-Cas9-mediated depletion of ENL led to anti-leukaemic effects, including increased terminal myeloid differentiation and suppression of leukaemia growth in vitro and in vivo. Biochemical and crystal structural studies and chromatin-immunoprecipitation followed by sequencing analyses revealed that ENL binds to acetylated histone H3, and co-localizes with H3K27ac and H3K9ac on the promoters of actively transcribed genes that are essential for leukaemia. Disrupting the interaction between the YEATS domain and histone acetylation via structure-based mutagenesis reduced the recruitment of RNA polymerase II to ENL-target genes, leading to the suppression of oncogenic gene expression programs. Notably, disrupting the functionality of ENL further sensitized leukaemia cells to BET inhibitors. Together, our data identify ENL as a histone acetylation reader that regulates oncogenic transcriptional programs in acute myeloid leukaemia, and suggest that displacement of ENL from chromatin may be a promising epigenetic therapy, alone or in combination with BET inhibitors, for aggressive leukaemia.
Martel J, Ojcius DM, Chang CJ, Lin CS, Lu CC, Ko YF, Tseng SF, Lai HC, Young JD
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Anti-obesogenic and antidiabetic effects of plants and mushrooms

NATURE REVIEWS ENDOCRINOLOGY 2017 MAR; 13(3):149-160
Obesity is reaching global epidemic proportions as a result of factors such as high-calorie diets and lack of physical exercise. Obesity is now considered to be a medical condition, which not only contributes to the risk of developing type 2 diabetes mellitus, cardiovascular disease and cancer, but also negatively affects longevity and quality of life. To combat this epidemic, anti-obesogenic approaches are required that are safe, widely available and inexpensive. Several plants and mushrooms that are consumed in traditional Chinese medicine or as nutraceuticals contain antioxidants, fibre and other phytochemicals, and have anti-obesogenic and antidiabetic effects through the modulation of diverse cellular and physiological pathways. These effects include appetite reduction, modulation of lipid absorption and metabolism, enhancement of insulin sensitivity, thermogenesis and changes in the gut microbiota. In this Review, we describe the molecular mechanisms that underlie the anti-obesogenic and antidiabetic effects of these plants and mushrooms, and propose that combining these food items with existing anti-obesogenic approaches might help to reduce obesity and its complications.
Wright MS, Ulrich MR, Fins JJ
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Guardianship and Clinical Research Participation: The Case of Wards with Disorders of Consciousness

KENNEDY INSTITUTE OF ETHICS JOURNAL 2017 MAR; 27(1):43-70
We review relevant federal law about research on human subjects and state laws on guardian authority to determine whether guardians can consent on behalf of their wards to participation in research. The Common Rule is silent on the issue as are most state guardianship laws. Our analysis shows significant variation in guardians' decision-making authority in the states that do regulate wards' participation in research. We consider how the appointment of guardians for patients with disorders of consciousness (DOC) impacts such patients' access to research. We assert that it is important that such persons be permitted to participate in research, so that their conditions and potential medical interventions can be studied, and that those with similar conditions can benefit from the knowledge gained from these studies. We argue that state guardianship laws should be adapted to specifically give guardians the authority to consent to research on behalf of wards who may be able to regain decisional capacity.
Kang JY
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Structural basis of transcription arrest by coliphage HK022 Nun in an

ELIFE 2017 MAR 20; 6(?):? Article e25478
Coliphage HK022 Nun blocks superinfection by coliphage lambda, by