Zebrafish: A See-Through Host and a Fluorescent Toolbox to Probe Host–Pathogen Interaction

In many ways, the zebrafish represents a hybrid between mouse and invertebrate infection models. Powerful forwardgenetic tools that have made invertebrates justifiably famous are not only relatively accessible in the zebrafish, but have been exploited to yield new insights into human infectious diseases, including leprosy and tuberculosis [1]. Transgenic technologies have enabled detailed, non-invasive in vivo visualization of macrophages and neutrophils in pitched battle with bacteria and fungi [2,3]. Reverse genetics with morpholinos, vivo-morpholinos, and zinc-finger nucleases (but unfortunately not homologous recombination, which for the moment remains out of reach in this organism) enable examination of the roles of specific genes during infection. Flexible genetic systems such as Gal4-UAS and Cre-Lox permit tissue-specific transformation and ablation ([3]; Figure 1)

Lipoprotein lipase regulates hematopoietic stem progenitor cell maintenance through DHA supply

Lipoprotein lipase (LPL) hydrolyzes triglycerides to supply free fatty acids (FFAs) to muscle for energy and adipocytes for storage. Here, the authors demonstrate that Lpl and its product, the FFA docosahexaenoic acid (DHA) are required for haematopoietic stem progenitor cell expansion during zebrafish embryogenesis