Modulating signaling networks by CRISPR/Cas9-mediated transposable element insertion

In a recent past, transposable elements (TEs) were referred to as selfish genetic components only capable of copying themselves with the aim of increasing the odds of being inherited. Nonetheless, TEs have been initially proposed as positive control elements acting in synergy with the host. Nowadays, it is well known that TE movement into host genome comprises an important evolutionary mechanism capable of increasing the adaptive fitness. As insights into TE functioning are increasing day to day, the manipulation of transposition has raised an interesting possibility of setting the host functions, although the lack of appropriate genome engineering tools has unpaved it. Fortunately, the emergence of genome editing technologies based on programmable nucleases, and especially the arrival of a multipurpose RNA-guided Cas9 endonuclease system, has made it possible to reconsider this challenge. For such purpose, a particular type of transposons referred to as miniature inverted-repeat transposable elements (MITEs) has shown a series of interesting characteristics for designing functional drivers. Here, recent insights into MITE elements and versatile RNA-guided CRISPR/Cas9 genome engineering system are given to understand how to deploy the potential of TEs for control of the host transcriptional activity.Fil: Vaschetto, Luis Maria Benjamin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Diversidad Animal I; Argentin

The large grey area between ‘bona fide’ and ‘rogue’ stem cell interventions — ethical acceptability and the need to include local variability

This article aims to put into perspective the binary opposition between ‘scientific’ clinical research trials and ‘rogue’ experimental stem cell therapies, and to show why the ethics criteria used by the dominant science community are not suitable for distinguishing between adequate and inadequate treatments. By focusing on the grey area between clinical stem cell trials and stem cell experimentation, the experimental space where patients, medical professionals and life scientists negotiate for diverging reasons and aims, I show why idealised notions of ethics are not feasible for many stem cell scientists in low- and middle-income countries. Drawing on fieldwork in China from 2012 to 2013, the article asks why ‘the unethical’ according to some is acceptable to Chinese life scientists. The case study of stem cell service provider Beike Biotech illustrates how stem cell interventions take place in a large grey area, where narrow notions of ethics are blurred with and supplanted by broader notions of ethics, co-determined by estimations of socio-economic, political and cultural understandings of risk, opportunity and benefit. I borrow the term ‘bionetworking’, understood as the entrepreneurial aspects of scientific networks that engage in creating biomedical products, to analyse various forms of medical experimentation. I speak of the ‘externalisation’ and ‘internalisation’ of local factors to elucidate how features of patient populations and their environments are subsumed in clinical research applications. Compared to polarised views of stem cell therapy, this approach increases the transparency of clinical interventions and broadens our understanding of why ‘stem cell tourism’ to some is ‘stem cell therapy’ to others

PDP-1 Links the TGF-β and IIS Pathways to Regulate Longevity, Development, and Metabolism

The insulin/IGF-1 signaling (IIS) pathway is a conserved regulator of longevity, development, and metabolism. In Caenorhabditis elegans IIS involves activation of DAF-2 (insulin/IGF-1 receptor tyrosine kinase), AGE-1 (PI 3-kinase), and additional downstream serine/threonine kinases that ultimately phosphorylate and negatively regulate the single FOXO transcription factor homolog DAF-16. Phosphatases help to maintain cellular signaling homeostasis by counterbalancing kinase activity. However, few phosphatases have been identified that negatively regulate the IIS pathway. Here we identify and characterize pdp-1 as a novel negative modulator of the IIS pathway. We show that PDP-1 regulates multiple outputs of IIS such as longevity, fat storage, and dauer diapause. In addition, PDP-1 promotes DAF-16 nuclear localization and transcriptional activity. Interestingly, genetic epistasis analyses place PDP-1 in the DAF-7/TGF-β signaling pathway, at the level of the R-SMAD proteins DAF-14 and DAF-8. Further investigation into how a component of TGF-β signaling affects multiple outputs of IIS/DAF-16, revealed extensive crosstalk between these two well-conserved signaling pathways. We find that PDP-1 modulates the expression of several insulin genes that are likely to feed into the IIS pathway to regulate DAF-16 activity. Importantly, dysregulation of IIS and TGF-β signaling has been implicated in diseases such as Type 2 Diabetes, obesity, and cancer. Our results may provide a new perspective in understanding of the regulation of these pathways under normal conditions and in the context of disease

Simulated annealing for calibrating the Manning’s roughness coefficients for general channel networks on a basin scale

The practical application of simultaneous solutions to the problem of steady state gradually varied flow in a general channel network depends significantly on the reliability of the estimated Manning roughness coefficients based on the calibration of the flow models against observed data. Manning roughness coefficients are needed for all the cross sections of the channel network. Systematic approaches for the calibration of Manning roughness coefficients for such a flow model are very sparse in the literature. This study proposes simulated annealing as an optimizer to the problem of calibrating Manning’s roughness coefficients for a steady state varied flow in a general channel network and presents its application to a case study in Quangnam basin of Vietnam