THE ANALYSIS OF PHENOTYPIC RESPONSES DUE TO POINT MUTATIONS ON SECRETED AND NON-SECRETED SERPINS IN CAENORHABDITIS ELEGANS

Open Access
Author:
Rosenstock, Philip Jay
Area of Honors:
Biochemistry and Molecular Biology
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Wendy Hanna Rose, Thesis Supervisor
  • Chen Pei David Tu, Honors Advisor
Keywords:
  • C. elegans
  • Caenorhabditis elegans
  • point mutations
  • serpins
  • serpin
  • phenotype
  • longevity
  • brood size
  • postembryonic development
Abstract:
Mutations in the human extracellular serpin, alpha-1 antitrypsin (A1AT) can lead to human disease phenotypes such as liver cirrhosis and emphysema. The most common “Z” variant possesses a mutation that causes accumulation in the endoplasmic reticulum (ER) of liver cells and as a result, a decline of normal plasma levels. Using a C. elegans model system, the expression of the Z variant of A1AT (ATZ) mimics the human disease through accumulation in the ER, lack of secretion, low number of progeny, slow development, and shortened lifespan. However, it has not been determined whether these phenotypes are strictly caused by protein misfolding in the ER or whether the expression of ATZ in the cytoplasm can yield similar phenotypes. Therefore, we have chosen to analyze the phenotypic responses caused by forcing wild-type A1AT (ATM) and ATZ into the cytoplasm of the C. elegans intestinal cells. We hypothesize that the phenotypes seen in animals expressing ATZ retained in the ER will also be present in transgenic animals expressing the cytoplasmic ATZ. Analyses were based upon the completion of longevity, postembryonic development, and brood size assays. A1AT forced into the cytoplasm was found to produce similar phenotypes to those animals possessing the same extracellular transgene. This finding suggests that regardless of cellular location, the aggregation of mutated A1AT causes these disease phenotypes.