Search results for "Termination"
showing 10 items of 780 documents
Fetal neurogenesis: breathe HIF you can.
2016
Blood vessels are part of the stem cell niche in the developing cerebral cortex, but their in vivo role in controlling the expansion and differentiation of neural stem cells (NSCs) in development has not been studied. Here, we report that relief of hypoxia in the developing cerebral cortex by ingrowth of blood vessels temporo‐spatially coincided with NSC differentiation. Selective perturbation of brain angiogenesis in vessel‐specific Gpr124 null embryos, which prevented the relief from hypoxia, increased NSC expansion at the expense of differentiation. Conversely, exposure to increased oxygen levels rescued NSC differentiation in Gpr124 null embryos and increased it further in WT embryos, s…
Scabrous overexpression in the eye affects R3/R4 cell fate specification and inhibits notch signaling
2015
Background Planar cell polarity (PCP) in the Drosophila eye is generated when immature ommatidial preclusters acquire opposite chirality in the dorsal and ventral halves of the eye imaginal disc and rotate 90 ° toward the equator. The scabrous (sca) gene is involved in R8 differentiation and in the correct spacing of ommatidial clusters in eye imaginal discs, but it was also suggested to be required during ommatidial rotation. However, no clear relationships between sca and other genes involved in the process were established. Results To explore the role of Sca in PCP establishment, we performed an RNAi-based modifier genetic screen using the rough eye phenotype of sca-overexpressing flies.…
Precision and accuracy of single-molecule FRET measurements-a multi-laboratory benchmark study
2018
Single-molecule Forster resonance energy transfer (smFRET) is increasingly being used to determine distances, structures, and dynamics of biomolecules in vitro and in vivo. However, generalized protocols and FRET standards to ensure the reproducibility and accuracy of measurements of FRET efficiencies are currently lacking. Here we report the results of a comparative blind study in which 20 labs determined the FRET efficiencies (E) of several dye-labeled DNA duplexes. Using a unified, straightforward method, we obtained FRET efficiencies with s.d. between +/- 0.02 and +/- 0.05. We suggest experimental and computational procedures for converting FRET efficiencies into accurate distances, and…
CHANGING THE NATIONAL HEIGHT SYSTEM AND GEOID MODEL IN LATVIA
2016
According to the decision of IAG Reference Frame Sub-commission for Europe (EUREF) the EVRF2007 solution as the vertical reference has to be deployed in EU countries.The new height system LAS-2000,5 had been enacted as the European Vertical Reference System‘s EVRF2007 realization in Latvia and the new geoid model LV‘14 had been introduced by Latvian authority Latvian Geospatial Information Agency. However, the appreciation of the quality of quasi-geoid model LV‘14 is rather contradictious among the users in Latvia. The independent estimate and comparison of the two Latvian geoid models developed till now has been performed by the Institute of Geodesy and Geoinformatics. Previous geoid model…
Nucleocytoplasmic transport of the RNA-binding protein CELF2 regulates neural stem cell fates.
2020
The development of the cerebral cortex requires balanced expansion and differentiation of neural stem/progenitor cells (NPCs), which rely on precise regulation of gene expression. Because NPCs often exhibit transcriptional priming of cell-fate-determination genes, the ultimate output of these genes for fate decisions must be carefully controlled in a timely fashion at the post-transcriptional level, but how that is achieved is poorly understood. Here, we report that de novo missense variants in an RNA-binding protein CELF2 cause human cortical malformations and perturb NPC fate decisions in mice by disrupting CELF2 nucleocytoplasmic transport. In self-renewing NPCs, CELF2 resides in the cyt…
Starvation resistance and tissue-specific gene expression of stress-related genes in a naturally inbred ant population
2016
Starvation is one of the most common and severe stressors in nature. Not only does it lead to death if not alleviated, it also forces the starved individual to allocate resources only to the most essential processes. This creates energetic trade-offs which can lead to many secondary challenges for the individual. These energetic trade-offs could be exacerbated in inbred individuals, which have been suggested to have a less efficient metabolism. Here, we studied the effect of inbreeding on starvation resistance in a natural population of Formica exsecta ants, with a focus on survival and tissue-specific expression of stress, metabolism and immunity-related genes. Starvation led to large tis…
Asymmetric cell division requires specific mechanisms for adjusting global transcription
2017
Most cells divide symmetrically into two approximately identical cells. There are many examples, however, of asymmetric cell division that can generate sibling cell size differences. Whereas physical asymmetric division mechanisms and cell fate consequences have been investigated, the specific problem caused by asymmetric division at the transcription level has not yet been addressed. In symmetrically dividing cells the nascent transcription rate increases in parallel to cell volume to compensate it by keeping the actualmRNA synthesis rate constant. This cannot apply to the yeast Saccharomyces cerevisiae, where this mechanism would provoke a neverending increasing mRNA synthesis rate in sma…
Trial Design and Endpoints in Hepatocellular Carcinoma: AASLD Consensus Conference
2020
Proper trial design is critical for the success of clinical investigations. Hepatocellular carcinoma (HCC) is a complex disease that has several unique properties. In 2008, after the approval of sorafenib, a panel of experts proposed guidelines for trial design and endpoints in HCC that have been instrumental during the last decade and provided a framework to allow an homogeneous analysis of reported investigations. Since then, several phase III studies have been reported and novel challenges have emerged. A panel of experts conveyed by AASLD organized a Special Topic Conference on trial design and endpoints to address those emerging challenges. This review summarizes the analysis and concl…
Prioritizing covariates in the planning of future studies in the meta-analytic framework
2016
Science can be seen as a sequential process where each new study augments evidence to the existing knowledge. To have the best prospects to make an impact in this process, a new study should be designed optimally taking into account the previous studies and other prior information. We propose a formal approach for the covariate prioritization, i.e., the decision about the covariates to be measured in a new study. The decision criteria can be based on conditional power, change of the p-value, change in lower confidence limit, Kullback-Leibler divergence, Bayes factors, Bayesian false discovery rate or difference between prior and posterior expectation. The criteria can be also used for decis…
Targeting Nonsense: Optimization of 1,2,4-Oxadiazole TRIDs to Rescue CFTR Expression and Functionality in Cystic Fibrosis Cell Model Systems
2020
Cystic fibrosis (CF) patients develop a severe form of the disease when the cystic fibrosis transmembrane conductance regulator (CFTR) gene is affected by nonsense mutations. Nonsense mutations are responsible for the presence of a premature termination codon (PTC) in the mRNA, creating a lack of functional protein. In this context, translational readthrough-inducing drugs (TRIDs) represent a promising approach to correct the basic defect caused by PTCs. By using computational optimization and biological screening, we identified three new small molecules showing high readthrough activity. The activity of these compounds has been verified by evaluating CFTR expression and functionality after…