Why I use zebrafish in my research
Helen Moore is a MRC-funded PhD student researching body clocks at University College London. Here she tells us why zebrafish are an ideal model for studying 24-hour rhythms.
Zebrafish have come a long way from their home in the Ganges River. Popular with aquarium owners, these colourful stripy silver and blue fish are becoming increasingly important to research.
Zebrafish began life in the lab as a common model for understanding development. They lay transparent eggs that can be easily collected and through which their developing organs can be seen. Check out this timelapse video of developing zebrafish.
Now research using zebrafish is improving knowledge in a long list of areas including cancer and tissue regeneration. Zebrafish develop tumours with a remarkable likeness to human ones, and so might be useful for screening anti-cancer drugs. Their amazing ability to regenerate and repair their tissue may help us to develop better treatments for damaged hearts.
But it’s the zebrafish body clock that I’m most interested in. Most of your body runs on a daily clock that responds to light as a time cue. The workings of the body clock have profound implications in many areas of health and disease, from severe conditions like cancer, to common ailments like asthma and hypertension. You may have noticed your tolerance to alcohol is lower at lunchtime than in the evening. This 24-hour variation in tolerance can also be true for some cancer treatments.
If we are going to use zebrafish to model human disorders, it’s best to know as much as possible about the biology of their body clocks. Like humans, zebrafish use light as a time cue, sleep at night and are most active during the day.
However, while only our eyes can directly detect light, their whole bodies can. So whereas a blind person without eyes may struggle to synchronise their clock daily, the same might not be true for zebrafish. During my PhD, I am determining whether the entire zebrafish brain is light sensitive or whether there are discrete areas that are more sensitive to light than others.
To do this, I’ve been looking at particular genes involved in controlling the body clock in zebrafish and when and where they are active in the brain over a 24-hour period. Because parts of the fish are transparent, it’s easy to see ‘markers’ of gene activity. I use a bioluminescent firefly protein that glows more strongly when the gene it is attached to is more active. This is providing me with clues about whether a zebrafish’s brain and eyes play an important role in synchronising the body clock.
There’s a lot to learn from this little fish. I hope that its role in biological knowledge and developing new treatments is secured.
Helen is currently taking part in an internship programme run by the Academy of Medical Sciences and the MRC. The internship scheme gives MRC-funded PhD students the opportunity to gain first-hand experience of a medical policy environment in the last years of their PhD studies. Applications for the 2013/14 internship placements are now open.