Ontogeny and behaviour of early macrophages in the zebrafish embryo

• DOI: 10.1242/dev.126.17.3735
• Publication Date: 2021-04-26T03:46:47Z
• Authors: Philippe Herbomel,; Bernard Thisse; Christine Thisse
• Keywords: Mesenchyme; Lateral plate mesoderm

Abstract In the zebrafish embryo, only known site of hemopoieisis is an intra-embryonic blood island at junction between trunk and tail that gives rise to erythroid cells. Using video-enhanced differential interference contrast microscopy, as well in-situ hybridization for expression two new hemopoietic marker genes, draculin leucocyte-specific plastin, we show macrophages appear in embryo least early cells, but originate from ventro-lateral mesoderm situated other end just anterior cardiac field. These macrophage precursors migrate yolksac, differentiate. From many invade mesenchyme head, while others join circulation. Apart phagocytosing apoptotic corpses, these were observed engulf destroy large amounts bacteria injected intravenously; also sensed presence into body cavities are isolated blood, migrated eradicated microorganisms. Moreover, although a fraction population goes infection, entire acquires activated behaviour, similar mammals. Our results support notion vertebrate embryos, endowed with proliferative capacity arise lineage through non-classical, rapid differentiation pathway, which bypasses monocytic series well-documented adult organs.