Divergent functions of the evolutionarily conserved, yet seemingly dispensable, Wnt target, sp5.

The activation of sp5 in response to Wnt/β-catenin signaling is observed in many species during axis patterning, neural crest induction, maintenance and differentiation of stem cells. Indeed, the conserved response of sp5 orthologs to Wnt-mediated activation is the basis for this gene commonly being used as a readout for Wnt signaling activity. However, several seemingly conflicting findings regarding the function of sp5 in the context of Wnt signaling cast this gene in an enigmatic light.

Pax2a, Sp5a and Sp5l act downstream of Fgf and Wnt to coordinate sensory-neural patterning in the inner ear.

In zebrafish, sensory epithelia and neuroblasts of the inner ear form simultaneously in abutting medial and lateral domains, respectively, in the floor of the otic vesicle. Previous studies support regulatory roles for Fgf and Wnt, but how signaling is coordinated is poorly understood. We investigated this problem using pharmacological and transgenic methods to alter Fgf or Wnt signaling from early placodal stages to evaluate later changes in growth and patterning.

Quantifiable Intravital Light Sheet Microscopy.

Live imaging of zebrafish embryos that maintains normal development can be difficult to achieve due to a combination of sample mounting, immobilization, and phototoxicity issues that, once overcome, often still results in image quality sufficiently poor that computer-aided analysis or even manual analysis is not possible. Here, we describe our mounting strategy for imaging the zebrafish midbrain-hindbrain boundary (MHB) with light sheet fluorescence microscopy (LSFM) and pilot experiments to create a study-specific set of parameters for semiautomatically tracking cellular movements in the embryonic midbrain primordium during zebrafish segmentation.

Navigating the Light-Sheet Image Analysis Software Landscape: Concepts for Driving Cohesion From Data Acquisition to Analysis.

From the combined perspective of biologists, microscope instrumentation developers, imaging core facility scientists, and high performance computing experts, we discuss the challenges faced when selecting imaging and analysis tools in the field of light-sheet microscopy. Our goal is to provide a contextual framework of basic computing concepts that cell and developmental biologists can refer to when mapping the peculiarities of different light-sheet data to specific existing computing environments and image analysis pipelines. We provide our perspective on efficient processes for tool selection and review current hardware and software commonly used in light-sheet image analysis, as well as discuss what ideal tools for the future may look like.

Building a three-dimensional model of early-stage zebrafish embryo brain.

We introduce a computational approach to build three-dimensional (3D) surface mesh models of the early-stage zebrafish brain primordia from time-series microscopy images. The complexity of the early-stage brain primordia and lack of recognizable landmarks pose a distinct challenge for feature segmentation and 3D modeling. Additional difficulty arises because of noise and variations in pixel intensity.