Apoptosis in Cnidarian/Algal Symbioses

Oregon State University, Corvallis OR

Investigators

Abstract

A grant has been awarded to Dr. Virginia Weis of Oregon State University and Dr. Douglas Green of the La Jolla Institute of Allergy and Immunology to examine programmed cell death, or apoptosis, in the beneficial symbiosis between a sea anemone, a cnidarian, and its singled-celled algae resident within its tissues. Apoptosis is a fundamental life process and has been well-characterized in higher animals but relatively poorly studied in more primitive groups such as cnidarians and algae. Weis and Green will describe apoptosis at the molecular and biochemical levels in the anemone/algae symbiosis. They will identify and characterize genes in these primitive organisms that are closely related to those found in higher animals, including humans. Finally, new state-of-the-art genetic techniques will be used to block the correct functioning of apoptosis gene products. This approach will help determine the role that apoptosis genes play in the regulation and maintenance of coral/algal symbioses. Apoptosis plays an important role throughout the lives of all animals. Numerous signals trigger the activation of a complex cascade of events that results in the rapid and orderly death of cells. Interest in apoptosis in the last decade has led to an explosion of information on the critical role of apoptosis in animal (including humans) development, aging, stress, and disease. To date, however, few investigators have focused on apoptosis in primitive animals. Understanding the evolutionary origin of apoptosis will provide valuable insight into the complexities of this process in vertebrates and humans. The sea anemone/algae symbiosis is closely related to the symbiotic relationship that comprises reef-building corals, and is an ideal model for the study of threatened corals. Corals form the trophic and structural foundation of the entire reef ecosystem and are therefore of fundamental ecological importance globally. Coral reefs are disappearing at an alarming rate worldwide, due in large part to the phenomenon of coral bleaching, which results from the breakdown of the coral/algal symbiosis. The cellular and molecular nature of bleaching is only beginning to be explored and apoptosis has been implicated as one possible mechanism of bleaching. The investigation of apoptosis in a cnidarian/algal symbiosis will be a first step towards a achieving a long-term goal of determining the role of apoptosis in coral bleaching.