The secret life of worms
Don't bother to look for AHFMR Scientist Dr. James McGhee in his office most Monday mornings—he'll be at the worm meeting.
Each week, 20 or 30 researchers from five University of Calgary labs get together to discuss their research on Caenorhabditis elegans, a tiny roundworm about one millimetre in length that lives in the soil. Dr. McGhee and his colleagues are not alone; thousands of researchers around the world study this worm. The popularity of C. elegans lies in the fact that, although it is a multicellular organism with about 1,000 cells, it is simple enough to be studied in great detail. Scientists have mapped out the developmental fate of every cell in C. elegans; in other words, they know where the cell comes from and what every cell will turn into.
"I set out to understand how an organism makes an intestine: what genes are turned on in the various parts of the digestive tract, what genes control them, and how it's all coordinated," says Dr. McGhee. "The beauty of studying this in C. elegans is that it is delightfully simple compared to our intestines. The entire intestine derives from one cell in the eight-celled embryo."
The worms are also masters of digestion. A single C. elegans eats double or triple its body mass—several million bacteria—every day. Each bacterium spends less than two minutes in the intestine; but in that time the worm can extract all the nutrients it needs.
Dr. McGhee's team has assembled a comprehensive list of all the genes produced in the C. elegans intestine, both in the embryo and in the adult. Their work points to one "master regulator", a specialized type of protein called a transcription factor that controls the process by which the information in a gene is made into something functional. This particular protein is produced in every cell of the intestine, from the time when the intestine consists of only two cells right through to the end of the worm's life. One of Dr. McGhee's goals is a complete analysis of the many roles played by this transcription factor in driving the development of the intestine.
"Of course, worms don't have the complex gastrointestinal system of mammals, but at a fundamental level the genes we are looking at in C. elegans are the same genes that control our own intestines," notes Dr. McGhee. "The power of this tiny worm as an experimental system is that understanding these fundamental processes may help explain how the regulatory pathways in the human intestine can go wrong and cause individuals to be susceptible to gastrointestinal diseases."