White plans to study tumor cell homing, then look for ways to modify the tumor cells or cells of the host so that the spreading cells never find their new location.
The fish may also answer questions about stem cell transplants. While transplants of blood-forming stem cells help cancer patients rebuild healthy blood, some transplants don't "take," for reasons that are unknown. Scientists have lacked a full understanding what steps blood stem cells must take to do their job, says White.
White showed the process is observable in the fish. He first irradiated a transparent fish's bone marrow, then transplanted fluorescent blood-forming stem cells from another zebrafish. By four weeks, the fluorescent stem cells had visibly migrated and grown in the fish's bone marrow, which is in the kidney. Even individual stem cells were visible, something researchers haven't easily observed in a living organism, White says.
By studying how the stem cells embed and build blood in the fish, scientists can look for ways to help patients rebuild their blood faster. Drugs and genes could be tested in the living fish, with direct observation of results, White says.
White created the transparent fish simply by mating two existing zebrafish breeds. Zebrafish have three pigments in their skinreflective, black, and yellow. White mated a breed that lacks reflective pigment, called "roy orbison," with one that lacks black pigment, called "nacre." The offspring had only yellow pigment in their skin, essentially looking clear. White named the new breed "casper."
The fish's brain, heart, and digestive tract are also visible, allowing researchers to study genetic defects of these organs from early embryonic development through adulthood. White hop
|Contact: Elizabeth Andrews|
Children's Hospital Boston