Transgenic Lines

In addition to a wild-type (WT) strain, our zebrafish facility houses several transgenic zebrafish lines. These strains are primarily used to study immunology, especially the function and behaviour of immune cells towards pathogens and other invaders, and determine which cells the invading pathogens have a predilection for.

This is done mostly by live imaging described in the technique section (link). Most transgenic lines were kindly provided by Prof. Stephen Renshaw from the University of Sheffield, UK and the transparent tra;nac line was provided by the Max Planck Institute for Developmental Biology, Tübingen, Germany.

List of Transgenic or Mutant Lines

tra;nac

A double mutant for transparent (tra) and nacre (nac) genotypes.

The transparent mutant phenotype is caused by a deletion in mpv17 gene that results in a loss or strong reduction of iridophores throughout larval and adult stages. The nacre mutant has a mutation in the mitfa gene, resulting in a complete loss of melanophores. When both these genes are non-functioning the fish is transparent and we are able to observe the inner organs through the skin.

Examples of investigations from our group using tra;nac zebrafish can be found here:

Antigen uptake during different life stages of zebrafish (Danio rerio) using a GFP-tagged Yersinia ruckeri.

Tg(mpx:GFP) i114

In this zebrafish strain, the myeloperoxidase (mpx, also called mpo) promoter expresses GFP (green fluorescence protein). In larval zebrafish, the myeloperoxidase enzyme expression is restricted to neutrophils and its precursors and thus emit green fluorescence when illuminated with a wave length of 488 nm.

This neutrophil reporter line, allows an excellent visualization of these cells and can be used to study neutrophil behavior especially for inflammation studies. Examples of investigations from our group using Tg(mpx:GFP) i114 zebrafish can be found here:

Association between adaptive immunity and neutrophil dynamics in zebrafish (Danio rerio) infected by a parasitic ciliate.

The dynamics of neutrophils in zebrafish (Danio rerio) during infection with the parasite Ichthyophthirius multifiliis.

Tg(fli1:EGFP)

Transgenic zebrafish line that expresses enhanced GFP in the entire vasculature under the control of the fli1 promoter, a known endothelial cell marker during vascular development, and thus enable the visualization of vasculature in live zebrafish.

Examples of investigations from our group using Tg(fli1:EGFP) zebrafish can be found here:

Zebrafish (Danio rerio) larvae as a model to study real-time propagating VHS virus infection, tropism and neutrophil activity. Accepted in Journal of Fish Diseases.

Tg(lyz:nfsB-mCherry)sh260

This is a neutrophil reporter line which expresses mCherry in the cytoplasm of zebrafish neutrophils when illuminated with a wave length of 540-590 nm. allowing visualization of the neutrophil migration in vivo.

Tg(mpeg1:mCherry-CAAX)

This is a macrophage reporter line that has a macrophage-specific marker - mpeg1 (macrophage expressed gene 1) expressing red fluorescent protein mCherry. Thus the macrophages in this line emit red fluorescence when illuminated with a wave length of 540-590 nm. Using this line we can study the different dynamic behaviors of macrophages after infection and injury.

By crossing the neutrophil and macrophage specific line, we are able to produce double-labelled Tg(mpeg1:mCherry) x Tg(mpx:GFP)i114 fish to study the macrophage and neutrophil interactions simultaneously.