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

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

CRISPR/Cas9: A New Genome Editing Tool to Accelerate Cotton (Gossypium spp.) Breeding

Cotton has a tremendous economic value worldwide due to its high-quality fiber, edible oil and protein contents. However, the intensifying scenario of human population expansion and global environmental changes demand a proportionate increase in cotton production. In the past, several successful attempts have been made by introgression of many quality- and yield-related traits into elite cotton cultivars through conventional breeding. However, those measures are time consuming due to the reliance on introgression of naturally-existing genetic variation through extensive backcrossing. Nonetheless, plant breeding can be accelerated through modern genome editing (GE) tools. Various GE techniques including zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), and clustered regularly interspaced palindromic repeats and CRISPR-associated proteins systems (CRISPR/Cas)-based approaches have been successfully employed for various crop plants. Among them, CRISPR/Cas-based approaches hold great GE potential due to their simplicity, competency and versatility. In cotton, this system can regulate the gene expression associated with quality traits, to circumscribe phytopathogens and/or to stack molecular traits at a desired locus. In gene stacking through site-specific endonucleases, the desired genes can be introduced in close proximity to a specific locus in the cotton genome with a low risk of segregation. However, such executions are tedious to achieve through classical breeding techniques. Moreover, through the CRISPR/Cas-based approaches, transgene-free cotton plants can easily be produced by selfing or backcrossing to meet the current genetically modified organisms (GMO) guidelines. In this chapter, we address the potential application of CRISPR/Cas-based approaches in available whole cotton genomes to sustain cotton productivity, and achieve genetic improvement, pathogen resistance and agronomic traits. Future prospects of GE applications in cotton breeding are also addressed.BITAK 2215We thank TUBITAK 2215 for providing a fully-funded PhD scholarship to Sarbesh Das Dangol

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