Figure ) and penetrating the tissue of zebrafish embryos (Figure ). Thus, the subcellular destinations of these molecules in zebrafish are important to investigate as well. To visualize compound distribution in the brain neuroepithelium, transgenic Zebrafish Tg(sox2: sox2-E2A-QF2) m1517 crossed with Tg(QUAS: nls-mCardinal) m1637 were used to label cell nuclei of neural stem and progenitor cells in vivo fluorescently red. Embryos were treated with 21 and 22, respectively, to investigate subcellular localization. Figure shows that the localization of 21 in the brain of the zebrafish appear to be predominantly cytoplasmic, while 22 appears to be also associated with membranes and vesicles.