Lineage labeling with zebrafish Cre and CreERT2 recombinase CRISPR knock-ins.

Background: The ability to generate endogenous Cre recombinase drivers using CRISPR-Cas9 knock-in technology allows lineage tracing, cell type specific gene studies, and validation of inferred developmental trajectories from phenotypic and gene expression analyses. This report describes endogenous zebrafish Cre and CreERT2 drivers generated with GeneWeld CRISPR-Cas9 precision targeted integration.

Results: and knock-ins crossed with ubiquitous -based Switch reporters led to broad labeling in expected mesodermal and neural crest-derived lineages in cardiac, pectoral fins, pharyngeal arch, liver, intestine, and mesothelial tissues, as well as enteric neurons.

Requirement of a novel gene, drish, in the zebrafish retinal ganglion cell and primary motor axon development.

Background: During neurogenesis, growing axons must navigate through the complex extracellular environment and make correct synaptic connections for the proper functioning of neural circuits. The mechanisms underlying the formation of functional neural networks are still only partially understood.

Results: Here we analyzed the role of a novel gene si:ch73-364h19.

Endocardium gives rise to blood cells in zebrafish embryos.

Previous studies have suggested that the endocardium contributes to hematopoiesis in murine embryos, although definitive evidence to demonstrate the hematopoietic potential of the endocardium is still missing. Here, we use a zebrafish embryonic model to test the emergence of hematopoietic progenitors from the endocardium. By using a combination of expression analysis, time-lapse imaging, and lineage-tracing approaches, we demonstrate that myeloid cells emerge from the endocardium in zebrafish embryos.

Single-cell transcriptomic analysis of vascular endothelial cells in zebrafish embryos.

Vascular endothelial cells exhibit substantial phenotypic and transcriptional heterogeneity which is established during early embryogenesis. However, the molecular mechanisms involved in establishing endothelial cell diversity are still not well understood. Zebrafish has emerged as an advantageous model to study vascular development.