Cleavage and polyadenylation specificity factor 30 Shimberg, Geoffrey D.; Michalek, Jamie L.; Oluyadi, Abdulafeez A. ...
Proceedings of the National Academy of Sciences - PNAS,
04/2016, Letnik:
113, Številka:
17
Journal Article
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Cleavage and polyadenylation specificity factor 30 (CPSF30) is a key protein involved in pre-mRNA processing. CPSF30 contains five Cys₃His domains (annotated as “zinc-finger” domains). Using ...inductively coupled plasma mass spectrometry, X-ray absorption spectroscopy, and UV-visible spectroscopy, we report that CPSF30 is isolated with iron, in addition to zinc. Iron is present in CPSF30 as a 2Fe–2S cluster and uses one of the Cys₃His domains; 2Fe–2S clusters with a Cys₃His ligand set are rare and notably have also been identified in MitoNEET, a protein that was also annotated as a zinc finger. These findings support a role for iron in some zinc-finger proteins. Using electrophoretic mobility shift assays and fluorescence anisotropy, we report that CPSF30 selectively recognizes the AU-rich hexamer (AAUAAA) sequence present in pre-mRNA, providing the first molecular-based evidence to our knowledge for CPSF30/RNA binding. Removal of zinc, or both zinc and iron, abrogates binding, whereas removal of just iron significantly lessens binding. From these data we propose a model for RNA recognition that involves a metaldependent cooperative binding mechanism.
Idiopathic REM sleep behavior disorder is a parasomnia characterized by dream enactment and is commonly a prediagnostic sign of parkinsonism and dementia. Since risk factors have not been defined, we ...initiated a multicenter case-control study to assess environmental and lifestyle risk factors for REM sleep behavior disorder.
Cases were patients with idiopathic REM sleep behavior disorder who were free of dementia and parkinsonism, recruited from 13 International REM Sleep Behavior Disorder Study Group centers. Controls were matched according to age and sex. Potential environmental and lifestyle risk factors were assessed via standardized questionnaire. Unconditional logistic regression adjusting for age, sex, and center was conducted to investigate the environmental factors.
A total of 694 participants (347 patients, 347 controls) were recruited. Among cases, mean age was 67.7 ± 9.6 years and 81.0% were male. Cases were more likely to smoke (ever smokers = 64.0% vs 55.5%, adjusted odds ratio OR = 1.43, p = 0.028). Caffeine and alcohol use were not different between cases and controls. Cases were more likely to report previous head injury (19.3% vs 12.7%, OR = 1.59, p = 0.037). Cases had fewer years of formal schooling (11.1 ± 4.4 years vs 12.7 ± 4.3, p < 0.001), and were more likely to report having worked as farmers (19.7% vs 12.5% OR = 1.67, p = 0.022) with borderline increase in welding (17.8% vs 12.1%, OR = 1.53, p = 0.063). Previous occupational pesticide exposure was more prevalent in cases than controls (11.8% vs 6.1%, OR = 2.16, p = 0.008).
Smoking, head injury, pesticide exposure, and farming are potential risk factors for idiopathic REM sleep behavior disorder.
Histone modifications, largely regulated by histone acetyltransferases (HAT) and histone deacetylases, have been recognized as major regulatory mechanisms governing human diseases, including cancer. ...Despite significant effort and recent advances, the mechanism by which the HAT and transcriptional coactivator p300 mediates tumorigenesis remains unclear. Here, we use a genetic and chemical approach to identify the microphthalmia-associated transcription factor (MITF) as a critical downstream target of p300 driving human melanoma growth. Direct transcriptional control of MITF by p300-dependent histone acetylation within proximal gene regulatory regions was coupled to cellular proliferation, suggesting a significant growth regulatory axis. Further analysis revealed forkhead box M1 (FOXM1) as a key effector of the p300-MITF axis driving cell growth that is selectively activated in human melanomas. Targeted chemical inhibition of p300 acetyltransferase activity using a potent and selective catalytic p300/CBP inhibitor demonstrated significant growth inhibitory effects in melanoma cells expressing high levels of MITF. Collectively, these data confirm the critical role of the p300-MITF-FOXM1 axis in melanoma and support p300 as a promising novel epigenetic therapeutic target in human melanoma. SIGNIFICANCE: These results show that MITF is a major downstream target of p300 in human melanoma whose expression is predictive of melanoma response to small-molecule inhibition of p300 HAT activity.
UVES and HIRES high-resolution spectra of Comet 9P/Tempel 1 are used to investigate the impact and rotational light curves of various species with a view toward building a simple model of the ...distribution and activity of the sources. The emission by OH, NH, CN, C
3, CH, C
2, NH
2, and OI, are analyzed, as well as the light scattered by the dust. It is found that a simple model reproduces fairly well the impact light curves of all species combining the production of the observed molecules and the expansion of the material throughout the slit. The impact light curves are consistent with velocities of 400–600 m/s. Their modeling requires a three-step dissociation sequence “Grand-Parent → Parent → Daughter” to produce the observed molecules. The rotational light curve for each species is explained in terms of a single model with three sources. The dust component can however not easily be explained that way.
AUF1 promotes let-7b loading on Argonaute 2 Yoon, Je-Hyun; Jo, Myung Hyun; White, Elizabeth J F ...
Genes & development,
2015-Aug-01, 2015-08-01, 20150801, Letnik:
29, Številka:
15
Journal Article
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Eukaryotic gene expression is tightly regulated post-transcriptionally by RNA-binding proteins (RBPs) and microRNAs. The RBP AU-rich-binding factor 1 (AUF1) isoform p37 was found to have high ...affinity for the microRNA let-7b in vitro (Kd = ∼ 6 nM) in cells. Ribonucleoprotein immunoprecipitation, in vitro association, and single-molecule-binding analyses revealed that AUF1 promoted let-7b loading onto Argonaute 2 (AGO2), the catalytic component of the RNA-induced silencing complex (RISC). In turn, AGO2-let-7 triggered target mRNA decay. Our findings uncover a novel mechanism by which AUF1 binding and transfer of microRNA let-7 to AGO2 facilitates let-7-elicited gene silencing.
Duchenne muscular dystrophy (DMD), a lethal X-linked disorder, is the most common and severe form of muscular dystrophies, affecting 1 in 3,500 male births. Mutations in the DMD gene lead to the ...absence of muscle dystrophin and a progressive degeneration of skeletal muscle. The possibility to treat DMD through cell therapy has been widely investigated. We have previously shown that human adipose-derived stromal cells (hASCs) injected systemically in SJL mice are able to reach and engraft in the host muscle, express human muscle proteins, and ameliorate the functional performance of injected animals without any immunosuppression. However, before starting clinical trials in humans many questions still need to be addressed in preclinical studies, in particular in larger animal models, when available. The best animal model to address these questions is the golden retriever muscular dystrophy (GRMD) dog that reproduces the full spectrum of human DMD. Affected animals carry a mutation that predicts a premature termination codon in exon 8 and a peptide that is 5% the size of normal dystrophin. These dogs present clinical signs within the first weeks and most of them do not survive beyond age two. Here we show the results of local and intravenous injections of hASCs into GRMD dogs, without immunosuppression. We observed that hASCs injected systemically into the dog cephalic vein are able to reach, engraft, and express human dystrophin in the host GRMD dystrophic muscle up to 6 months after transplantation. Most importantly, we demonstrated that injecting a huge quantity of human mesenchymal cells in a large-animal model, without immunosuppression, is a safe procedure, which may have important applications for future therapy in patients with different forms of muscular dystrophies.
The 12C14N/12C15N and 12C14N/13C14N isotopic ratios are determined for the first time in a Jupiter-family comet, 88P/1981 Q1 Howell, and in the chemically peculiar Oort Cloud comet C/1999 S4 ...(LINEAR). By comparing these measurements to previous ones derived for six other Oort Cloud comets (including one of Halley-type), we find that both the carbon and nitrogen isotopic ratios are constant within the uncertainties. The mean values are 12C/13C $\simeq$ 90 and 14N/15N $\simeq145$ for the eight comets. These results strengthen the view that CN radicals originate from refractory organics formed in the protosolar molecular cloud and subsequently incorporated in comets.
High-temperature (120-200 °C) polymer electrolyte membrane fuel cells (HT-PEMFCs) are promising energy conversion devices that offer multiple advantages over the established low-temperature (LT) ...PEMFC technology, namely: faster reaction kinetics, improved impurity tolerance, simpler water and thermal management, and increased potential to utilise waste heat. Whilst HT- and LT-PEMFCs share several components, important differences in the membrane materials, transport mechanisms and operating conditions provide new challenges and considerations for characterisation. This review focuses on phosphoric acid-doped HT-PEMFCs and provides a detailed discussion of the similarities and differences compared to LT-PEMFCs, as well as state-of-the-art performance and materials. Commonly used characterisation techniques including electrochemical, imaging, and spectroscopic methods are reviewed with a focus on use in HT-PEMFCs, how experimentation or analyses differ from LT-PEMFCs, and new opportunities for research using these techniques. Particular consideration is given to the presence of phosphoric acid and the absence of liquid water. The importance of accelerated stress tests for effective characterisation and durability estimation for HT-PEMFCs is discussed, and existing protocols are comprehensively reviewed focusing on acid loss, catalyst layer degradation, and start-up/shutdown cycling. The lack of standardisation of these testing protocols in HT-PEMFC research is highlighted as is the need to develop such standards.
High-temperature polymer electrolyte membrane fuel cells require advancements to capitalise on their advantages over conventional PEMFCs, the critical roles and opportunities for characterisation and durability testing are discussed in this review.
A contrast enhancement agent is used to visualise phosphoric acid penetration and distribution in high-temperature polymer electrolyte membrane fuel cells. This new method is demonstrated in the ...investigation of hot-pressing parameters on phosphoric acid penetration and distribution. In situ radiography of the hot-press process showed acid plumes breaking through the catalyst layer, microporous layer (MPL) and gas diffusion layer (GDL). The phosphoric acid volume and distribution within the MPL and GDL are quantified, and their dependence on hot-press pressure, duration and compression control are analysed. Increasing hot-press pressure and duration was found to increase acid penetration and delamination of the membrane and catalyst layers. The absence of a compression control gasket also led to significant infiltration into the MPL and GDL. Penetration occurred first at the anode for all tests, which was attributed to a higher number of cracks and greater degree of crack connectivity. Phosphoric acid entered the MPL and GDL either through initial breakthrough of the catalyst layer, or from acid pooling on the GDL surface and being compressed into the fibres. This work provides a novel method to improve visualisation of phosphoric acid and highlights the acid loss mechanisms resulting from hot-press conditions.
•In situ radiography of phosphoric acid penetration in HT-PEMFCs.•Novel contrast agent method to improve phosphoric acid visualisation.•Quantification of phosphoric acid in GDLs using X-ray computed tomography.•Analysis of effects of hot-press pressure, duration, and compression on distribution.•High pressure and lack of compression gasket led to most significant penetration.
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