The Isolation of Suppressors in the apl-1 Gene Pathway of C. elegans

Richard Malins
Boston University

Alzheimer's disease (AD) is a progressive, neurodegenerative disorder characterized by memory loss and language deterioration. The pathology of AD includes the deposition of dense plaques and the formation of neurofibrillary tangles in the brain. The neurotoxicity of these plaques may result in the cognitive dysfunction observed in AD patients. The major component of these dense plaques is the beta-amyloid peptide, which is a cleavage product of the Amyloid Precursor Protein (APP). There are several forms of APP and related proteins present in humans, and there is an APP-related family of proteins that is conserved in other animal species as well. One such species is Caenorhabditis elegans, the common soil-dwelling nematode. C. elegans is a model organism for genetic study because it has a short life cycle, its genes are easily manipulated, and its entire genome has been sequenced. APL-1 is the APP-like protein encoded by the apl-1 gene in C. elegans. Because of its similarity to human APP, APL-1 provides a reference for future studies of APP in humans. The apl-1 gene is essential to the survival of C. elegans: when it is non-functional, the animal dies. Our research has focused on suppressing the lethality associated with the loss of apl-1 function in C. elegans. This suppressor analysis may identify other genes that function with apl-1 and provide clues for how APP may act in humans. To date, 6978 mutagenized haploid genomes have been screened for mutations that revert the apl-1 lethality.