Researchers study the zebrafish (Danio rerio) to understand fundamental processes in development and physiology, and to shed light on mechanisms of human diseases. In humans, like in all mammals, blood cells are made from stem cells in the bone marrow, but in adult fish, the primary source is stem cells in the kidney. During a short period in their development, baby zebrafish make blood cells from stem cells located in a tissue in the tail called caudal hematopoietic tissue (CHT), shown here in green. The stem cells move from elsewhere in the embryo to the CHT where they proliferate, and eventually migrate to their final home in the kidney. Blood stem cell migration happens in a very similar manner during mammalian development. This is also the path by which donor blood stem cells migrate into the bone marrow of a patient during bone marrow transplantation. Unlike the bone marrow in mammals, the migration of stem cells can be visualized in a living zebrafish using a confocal microscope—a great advantage of using these fish to study the mechanisms of healthy blood cell formation, and of diseases of the blood, such as leukemia.
October is Chronic Myeloid Leukemia (CML) Awareness Month
Image courtesy of Elliott J. Hagedorn PhD and HHMI Investigator Leonard I. Zon MD, Boston Children's Hospital, Boston, MA
Different color stains were used to see various structures in this two-day-old zebrafish embryo: neurons (red), blood vessels (green), and nuclei (blue). The image was collected using a spinning disk confocal microscope.