Optimising the zebrafish Cre/Lox toolbox. Codon improved iCre, new gateway tools, Cre protein and guidelines.

We recently introduced the Cre/Lox technology in our laboratory for both transient (mRNA injections) and stable/transgenic experiments. We experienced significant issues such as silencing, mosaicism, and partial recombination using both approaches. Reviewing the literature gave us the impression that these issues are common among the zebrafish community using the Cre/Lox system.

Pipeline for generating stable large genomic deletions in zebrafish, from small domains to whole gene excisions.

Here we describe a short feasibility study and methodological framework for the production of stable, CRISPR/Cas9-based, large genomic deletions in zebrafish, ranging from several base pairs (bp) to hundreds of kilobases (kb). Using a cocktail of four single guide RNAs (sgRNAs) targeting a single genomic region mixed with a marker-sgRNA against the pigmentation gene tyrosinase, we demonstrate that one can easily and accurately excise genomic regions such as promoters, protein domains, specific exons, or whole genes. We exemplify this technique with a complex gene family, neurexins, composed of three duplicated genes with multiple promoters and intricate splicing processes leading to thousands of isoforms.

Neurexins in autism and schizophrenia-a review of patient mutations, mouse models and potential future directions.

Mutations in the family of neurexins (NRXN1, NRXN2 and NRXN3) have been repeatedly identified in patients with autism spectrum disorder (ASD) and schizophrenia (SCZ). However, it remains unclear how these DNA variants affect neurexin functions and thereby predispose to these neurodevelopmental disorders. Understanding both the wild-type and pathologic roles of these genes in the brain could help unveil biological mechanisms underlying mental disorders.

Tmem2 Regulates Embryonic Vegf Signaling by Controlling Hyaluronic Acid Turnover.

Angiogenesis is responsible for tissue vascularization during development, as well as in pathological contexts, including cancer and ischemia. Vascular endothelial growth factors (VEGFs) regulate angiogenesis by acting through VEGF receptors to induce endothelial cell signaling. VEGF is processed in the extracellular matrix (ECM), but the complexity of ECM control of VEGF signaling and angiogenesis remains far from understood.

Repositioning drugs for inflammatory disease - fishing for new anti-inflammatory agents.

Inflammation is an important and appropriate host response to infection or injury. However, dysregulation of this response, with resulting persistent or inappropriate inflammation, underlies a broad range of pathological processes, from inflammatory dermatoses to type 2 diabetes and cancer. As such, identifying new drugs to suppress inflammation is an area of intense interest.

Vegfd can compensate for loss of Vegfc in zebrafish facial lymphatic sprouting.

Lymphangiogenesis is a dynamic process that involves the sprouting of lymphatic endothelial cells (LECs) from veins to form lymphatic vessels. Vegfr3 signalling, through its ligand Vegfc and the extracellular protein Ccbe1, is essential for the sprouting of LECs to form the trunk lymphatic network. In this study we determined whether Vegfr3, Vegfc and Ccbe1 are also required for development of the facial and intestinal lymphatic networks in the zebrafish embryo.