STAT2-dependent induction of RNA adenosine deaminase ADAR1 by type I interferon differs between mouse and human cells in the requirement for STAT1

AbstractExpression of adenosine deaminase acting on RNA1 (ADAR1) is driven by alternative promoters. Promoter PA, activated by interferon (IFN), produces transcripts that encode the inducible p150 ADAR1 protein, whereas PB specifies the constitutively expressed p110 protein. We show using Stat1−/−, Stat2−/− and IRF9−/− MEFs that induction of ADAR1 p150 occurs by STAT2- and IRF9-dependent signaling that is enhanced by, but not obligatorily dependent upon, STAT1. Chromatin immunoprecipitation analysis demonstrated STAT2 at the PA promoter in IFN-treated Stat1−/− cells, whereas IFN-treated wild-type cells showed both STAT1 and STAT2 bound at PA. By contrast, with human 2fTGH cells and mutants U3A or U6A, ADAR1 induction by IFN was dependent upon both STAT1 and STAT2. These results suggest that transcriptional activation of Adar1 by IFN occurs in the absence of STAT1 by a non-canonical STAT2-dependent pathway in mouse but not human cells

Trade Facilitation in EAC Customs Union: Its Achievement and Implementation in Tanzania

This study addresses trade facilitation in the East African Community Customs Union (EAC CU) by tracking the achievements and implementation using Tanzania as a case. The study uses descriptive research design and data for the study were mainly secondary data; unstructured interviews with key stakeholders complemented data for this study. The study found that as a result of implementation of trade facilitation initiatives, performance in trade, FDI inflows and trade taxes collection in all EAC countries have improved significantly. Tanzania performs better than other EAC countries in FDI inflows and contribution of export to the Gross Domestic Product (GDP). The study found a significant positive relationship between countries’ trade facilitation and export performance. Facilitation was found to have no significant relationship on FDI flows. The major setbacks of trade facilitation are non-tariff barriers, transport infrastructure, inadequate human resources capacity, and low level of automation. Addressing these challenges will enhance EAC countries benefits from trade. Keywords: trade facilitation performance, trade facilitation and logistics indicators, EAC Customs Unio

The integration of semiotic resources and modalities in the teaching of geometry in a Grade 9 class in a South African high school: The four cases of congruency

In this article we examine the nature of inter-semiotic and intermodal construction in the exposition of a solution for a geometry rider. In the tradition of hermeneutic phenomenology, this case study involved an exploration of the oral discourse and visual texts used in a mathematics lesson. This research was intended to contribute to the understanding of the difficulties in teaching and learning geometry at school level. Results indicate that relational markings, oral and visual modalities in conjunction with gesturing constitute the primary semiotic resources employed by the teacher. This leads to the conclusion that the semiotic perspective, in conjunction with other perspectives on geometry teaching in schools, may provide a mechanism by which to reflect on the complexity of geometry teaching and learning in schools. Keywords: argumentation; congruency; diagrams; geometry; geometry riders; logical; relational markings; semiotics; spatial reasoning; teaching and learning; visual text

The search for an identification of amino acids, nucleobases and nucleosides in samples returned from Mars

The Mars Sample Return mission will provide us with a unique source of material from our solar system; material which could advance our knowledge of the processes of chemical evolution. As has been pointed out, Mars geological investigations based on the Viking datasets have shown that primordial Mars was in many biologically important ways similar to the primordial Earth; the presence of surface liquid water, moderate surface temperatures, and atmosphere of carbon dioxide and nitrogen, and high geothermal heat flow. Indeed, it would seem that conditions on Earth and Mars were fundamentally similar during the first one billion years or so. As has been pointed out, Mars may well contain the best preserved record of the events that transpired on the early planets. Examination of that early record will involve searching for many things, from microfossils to isotopic abundance data. We propose an investigation of the returned Mars samples for biologically important organic compounds, with emphases on amino acids, the purine and pyrimidine bases, and nucleosides

The search for and identification of amino acids, nucleobases and nucleosides in samples returned from Mars

An investigation of the returned Mars samples for biologically important organic compounds, with emphasis on amino acid, the puring and pyrimidine bases, and nucleosides is proposed. These studies would be conducted on subsurface samples obtained by drilling past the surface oxidizing layer with emphasis on samples containing the larges quantities of organic carbon as determined by the rover gas chromatographic mass spectrometer (GCMS). Extraction of these molecules from the returned samples will be performed using the hydrothermal extraction technique described by Cheng and Ponnamperuma. More rigorous extraction methods will be developed and evaluated. For analysis of the extract for free amino acids or amino acids present in a bound or peptidic form, aliquots will be analyzed by capillary GCMS both before and after hydrolysis with 6N hydrochloric acid. Establishment of the presence of amino acids would then lead to the next logical step which would be the use of chiral stationary gas chromatography phases to determine the enatiomeic composition of the amino acids present, and thus potentially establish their biotic or abiotic origin. Confirmational analyses for amino acids would include ion-exchange and reversed-phase liquid chromatographic analysis. For analyses of the returned Mars samples for nucleobases and nucleosides, affinity and reversed-phase liquid chromatography would be utilized. This technology coupled with scanning UV detection for identification, presents a powerful tool for nucleobase and nucleoside analysis. Mass spectrometric analysis of these compounds would confirm their presence in samples returned form Mars

Downregulation of FGF Signaling by Spry4 Overexpression Leads to Shape Impairment, Enamel Irregularities, and Delayed Signaling Center Formation in the Mouse Molar.

FGF signaling plays a critical role in tooth development, and mutations in modulators of this pathway produce a number of striking phenotypes. However, many aspects of the role of the FGF pathway in regulating the morphological features and the mineral quality of the dentition remain unknown. Here, we used transgenic mice overexpressing the FGF negative feedback regulator Sprouty4 under the epithelial keratin 14 promoter (K14-Spry4) to achieve downregulation of signaling in the epithelium. This led to highly penetrant defects affecting both cusp morphology and the enamel layer. We characterized the phenotype of erupted molars, identified a developmental delay in K14-Spry4 transgenic embryos, and linked this with changes in the tooth developmental sequence. These data further delineate the role of FGF signaling in the development of the dentition and implicate the pathway in the regulation of tooth mineralization. © 2019 The Authors. JBMR Plus is published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research