mpeg1 promoter transgenes direct macrophage-lineage expression in zebrafish

Abstract

Macrophages and neutrophils play important roles during the innate immune response, phagocytosing invading microbes and delivering antimicrobial compounds to the site of injury. Functional analyses of the cellular innate immune response in zebrafish infection/ inflammation models have been aided by transgenic lines with fluorophore-marked neutrophils. However, it has not been possible to study macrophage behaviors and neutrophil/macrophage interactions in vivo directly because there has been no macrophage-only reporter line. To remove this roadblock, a macrophagespecific marker was identified (mpeg1) and its promoter used in mpeg1-driven transgenes. mpeg1-driven transgenes are expressed in macrophage-lineage cells that do not express neutrophil-marking transgenes. Using these lines, the different dynamic behaviors of neutrophils and macrophages after wounding were compared side-by-side in compound transgenics. Macrophage/neutrophil interactions, such as phagocytosis of senescent neutrophils, were readily observed in real time. These zebrafish transgenes provide a new resource that will contribute to the fields of inflammation, infection, and leukocyte biology. (Blood. 2011;117(4): e49-e56)

Live Imaging Reveals Differing Roles of Macrophages and Neutrophils during Zebrafish Tail Fin Regeneration

“…3B, n ϭ 13). The injured embryos were immediately viewed under a confocal microscope at 3-min intervals for 48 h. Results showed that, similar what was noted in the previous reports (14,15), both types of myeloid cells responded immediately, but they migrated into the wound at different speeds (Fig. 3, A-D, n Ն 9; supplemental Movie 1, n ϭ 3).…”

“…By utilizing the Tg(coro1a:eGFP;lyz:Dsred) double transgenic lines, the in vivo behaviors and functions of macrophages and neutrophils in the larva tail fin regeneration (14,15,38,39) were directly assayed in a living embryo. We showed that upon injury, the local resident macrophages and neutrophils (Fig.…”

A non-canonical function of telomerase RNA in the regulation of developmental myelopoiesis in zebrafish

“…The casper mutant 56 and Tg(gata1::DsRed) 57 lines were previously described. The transgenics lines Tg(lyz::DsRed) 25 , Tg(mpx::eGFP) 24 , Tg(mpeg1::GAL4/uas::NTRmCherry) (mpeg1::mCherry was used throughout this manuscript for clarity) 26 and Tg(cd41::eGFP) 31 were kindly provided by Drs P. Crosier, S. Renshaw, G. Lieschke and R.I. Handin, respectively.…”

“…2b). To examine whether macrophages were affected, a tg(mpeg1:mCherry) line was used that has red fluorescent macrophages 26 . The number of macrophages was also reduced in TR-deficient larvae (Fig.…”

Insights from Genetic Models of Melanoma in Fish

“…However, cells of the mature adaptive immune system emerge later, at around 1 week of larval life [49,50], giving us the advantage of distinguishing between the contribution of the innate immune cells and the adaptive immune system in various processes involving the immune system in larval zebrafish. Moreover, zebrafish transgenic lines that have fluorescently labeled leukocyte subtypes in different colors are available [51][52][53], allowing easy in vivo observations under a fluorescent microscope. Zebrafish melanoma models were used by Feng [54] to delineate possible early interactions between oncogenetransformed melanoblasts and goblet cells and the immune system in the skin of zebrafish larvae.…”