Fruit Flies, Death, and Immunity

Mar 28, 2007

University of Arkansas scientists have found an important mechanism that regulates the destruction of larval fruit fly salivary glands that could point the way to understanding programmed cell death in the human immune system.

Biology professor Michael Lehmann, graduate student Chike Cao and research assistant Yanling Liu recently published their findings in the Journal of Cell Biology.

Lehmann and his colleagues examined the expression of different proteins during the development and demise of larval salivary glands in Drosophila melanogaster, a common fruit fly. Previous studies have shown that steroids and other hormones trigger programmed cell death during normal development, such as the destruction of the tadpole tail during frog metamorphosis. However, little was known about what tells these hormones to act on a specific tissue at a given time.

"We wanted to know why one cell dies during steroid hormone release, while another one doesn't," Lehmann said.

Cell death, it turns out, is essential to life - without it, normal development can't take place, and this sometimes results in premature death. Lehmann points out that cancer cells have a defect in their cell death program, which is why they grow unchecked. Thus, understanding the mechanisms that control cell death can give scientists insights into how such deaths preserve life.

While investigating the Drosophila model, the researchers found that the life and death of the salivary gland cells depend upon a member of the Fork head protein family. This protein first protects the salivary glands from steroid-triggered death by acting as a "traffic cop," preventing the activation of two key genes responsible for cell death. However, the protein then disappears after a particular steroid pulse in a sequence of pulses. A subsequent steroid pulse triggers the death of the salivary gland cells.

To determine the extent of involvement of this protein, the researchers removed this protein at an earlier stage in development, which led to the activation of the cell-killing genes by an earlier steroid pulse and to premature cell death. Further, when the scientists caused the continued presence of the Fork head protein, the cell death genes remained inactive and the cells continued to live past their normal life span.

These findings have implications beyond fruit flies, as the molecular machinery that controls cell death is largely similar for invertebrates and vertebrates. The Fork head protein in Drosophila has homologs in humans, called FOXAs. These FOXAs are known to work together with corticosteroids, which control cell death in the immune system and are in therapeutic use to suppress allergic and inflammatory responses.

"Our research suggests that the FOXAs might have a similar role in cell death control in the immune system," Lehmann said. "This gives medical researchers a direction in which they might want to look."

Source: University of Arkansas

Explore further: Full-annual-cycle models track migratory bird populations throughout the year

add to favorites email to friend print save as pdf

Related Stories

Evolving robot brains

8 hours ago

Researchers are using the principles of Darwinian evolution to develop robot brains that can navigate mazes, identify and catch falling objects, and work as a group to determine in which order they should ...

Facebook fends off telecom firms' complaints

8 hours ago

Facebook founder Mark Zuckerberg fended off complaints on Monday that the hugely popular social network was getting a free ride out of telecom operators who host its service on smartphones.

Scientists find clues to cancer drug failure

8 hours ago

Cancer patients fear the possibility that one day their cells might start rendering many different chemotherapy regimens ineffective. This phenomenon, called multidrug resistance, leads to tumors that defy ...

Glass coating improves battery performance

8 hours ago

Lithium-sulfur batteries have been a hot topic in battery research because of their ability to produce up to 10 times more energy than conventional batteries, which means they hold great promise for applications ...

Recommended for you

Activating genes on demand

9 hours ago

When it comes to gene expression - the process by which our DNA provides the recipe used to direct the synthesis of proteins and other molecules that we need for development and survival - scientists have ...

Metabolic path to improved biofuel production

10 hours ago

Researchers with the Energy Biosciences Institute (EBI), a partnership that includes the Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley, have found a way ...

Deadly frog fungus dates back to 1880s, studies find

12 hours ago

A deadly fungus responsible for the extinction of more than 200 amphibian species worldwide has coexisted harmlessly with animals in Illinois and Korea for more than a century, a pair of studies have found.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.