What do crabs and cancer have in common, other than both being signs of the zodiac? A Colorado State University professor says that the same genes that control growth in crustaceans are involved in abnormal cell growth in cancer.
“At the cellular level, the molecular mechanisms controlling growth are highly conserved in all organisms, from yeast to humans,” said Don Mykles, a professor in the Department of Biology. “Although it is not the primary objective, what we learn about growth regulation in crustaceans will certainly inform us about how hormones promote cancer in humans.”
Through a new $982,000 four-year grant from the National Science Foundation, Mykles will lead a team from CSU and three other universities to create a complete catalog of genes that are expressed in the crustacean molting gland. His hypothesis is that genes that trigger the molting process will include mTOR, a protein that controls cell growth rate, and transforming growth factor beta, a protein that controls cell differentiation. The project uses the blackback land crab, a Caribbean species well-suited for these studies. “As an air-breather, land crabs are easy to keep in the lab and we can easily manipulate molting,” Mykles said.
Crabs, lobsters and shrimp are ecologically and economically important crustaceans in marine environments. The hard shell provides protection and support, but restricts growth. As a result, these animals must periodically shed the shell, a process called molting. Upon molting, animals stretch the new shell before it hardens, providing more space for tissue growth. The entire process is controlled by molting hormone produced by a pair of molting glands. The activity of the molting gland is controlled, in turn, by environmental signals mediated by the nervous system.
“Little is known about the signaling genes that control the molting gland, in particular the genes required for committing the animal to molt. This ‘point of no return’ decision is critical for survival and growth in all crustaceans and is influenced by environmental factors, such as temperature and light. Our goal is to gain a better understanding of the complex interactions between signaling pathways that determine when a crab molts. We anticipate cataloging between 40,000 and 50,000 genes. Not all of these genes are directly involved in molt regulation. We will focus on those genes that change in expression at critical molt stages” said Mykles.
The research will identify genes essential for the activation of the molting gland and its regulation, both positive and negative, by environmental signals. This database will be made available to researchers to better understand how to manage fisheries, develop effective aquaculture practices and mitigate the harmful effects of pollutants and climate change. The research also is applicable to insects.
“Molt control is fundamentally the same in insects and crustaceans, so what we learn from the land crab can be applied to insects,” Mykles said.