miR-1/206 downregulates splicing factor Srsf9 to promote C2C12 differentiation.

Background: Myogenesis is driven by specific changes in the transcriptome that occur during the different stages of muscle differentiation. In addition to controlled transcriptional transitions, several other post-transcriptional mechanisms direct muscle differentiation. Both alternative splicing and miRNA activity regulate gene expression and production of specialized protein isoforms.

Author Correction: Epoxyeicosatrienoic acids enhance embryonic haematopoiesis and adult marrow engraftment.

An Amendment to this paper has been published and can be accessed via a link at the top of the paper.

High-content screen for modifiers of Niemann-Pick type C disease in patient cells.

Niemann-Pick type C (NPC) disease is a rare lysosomal storage disease caused primarily by mutations in NPC1. NPC1 encodes the lysosomal cholesterol transport protein NPC1. The most common NPC1 mutation is a missense mutation (NPC1I1061T) that causes misfolding and rapid degradation of mutant protein in the endoplasmic reticulum.

Estrogen receptor profiling and activity in cardiac myocytes.

Estrogen signaling appears critical in the heart. However a mechanistic understanding of the role of estrogen in the cardiac myocyte is lacking. Moreover, there are multiple cell types in the heart and multiple estrogen receptor (ER) isoforms.

Epoxyeicosatrienoic acids enhance embryonic haematopoiesis and adult marrow engraftment.

Haematopoietic stem and progenitor cell (HSPC) transplant is a widely used treatment for life-threatening conditions such as leukaemia; however, the molecular mechanisms regulating HSPC engraftment of the recipient niche remain incompletely understood. Here we develop a competitive HSPC transplant method in adult zebrafish, using in vivo imaging as a non-invasive readout. We use this system to conduct a chemical screen, and identify epoxyeicosatrienoic acids (EETs) as a family of lipids that enhance HSPC engraftment.

Prolonged Cre expression driven by the α-myosin heavy chain promoter can be cardiotoxic.

Studying the importance of genetic factors in a desired cell type or tissue necessitates the use of precise genetic tools. With the introduction of bacteriophage Cre recombinase/loxP mediated DNA editing and promoter-specific Cre expression, it is feasible to generate conditional knockout mice in which particular genes are disrupted in a cell type-specific manner in vivo. In cardiac myocytes, this is often achieved through α-myosin heavy chain promoter (αMyHC)-driven Cre expression in conjunction with a loxP-site flanked gene of interest.

Measuring microRNA reporter activity in skeletal muscle using hydrodynamic limb vein injection of plasmid DNA combined with in vivo imaging.

Background: microRNA regulation plays an important role in the remodeling that occurs in response to pathologic and physiologic stimuli in skeletal muscle. In response to stress, microRNAs are dynamically regulated, resulting in a widespread "fine-tuning" of gene expression. An understanding of this dynamic regulation is critical to targeting future therapeutic strategies.

A novel chemical screening strategy in zebrafish identifies common pathways in embryogenesis and rhabdomyosarcoma development.

The zebrafish is a powerful genetic model that has only recently been used to dissect developmental pathways involved in oncogenesis. We hypothesized that operative pathways during embryogenesis would also be used for oncogenesis. In an effort to define RAS target genes during embryogenesis, gene expression was evaluated in Tg(hsp70-HRAS(G12V)) zebrafish embryos subjected to heat shock.

Ubiquitous transgene expression and Cre-based recombination driven by the ubiquitin promoter in zebrafish.

Molecular genetics approaches in zebrafish research are hampered by the lack of a ubiquitous transgene driver element that is active at all developmental stages. Here, we report the isolation and characterization of the zebrafish ubiquitin (ubi) promoter, which drives constitutive transgene expression during all developmental stages and analyzed adult organs. Notably, ubi expresses in all blood cell lineages, and we demonstrate the application of ubi-driven fluorophore transgenics in hematopoietic transplantation experiments to assess true multilineage potential of engrafted cells.

Retro-orbital injection in adult zebrafish.

Drug treatment of whole animals is an essential tool in any model system for pharmacological and chemical genetic studies. Intravenous (IV) injection is often the most effective and noninvasive form of delivery of an agent of interest. In the zebrafish (Danio rerio), IV injection of drugs has long been a challenge because of the small vessel diameter.