Phenotypic Characterization of PNPase Mutation and Overexpression in C. elegans

PNPase, polynucleotide phosphorylase, is a multifunctional exoribonuclease protein with 3` terminal oligonucleotide polymerase activity. Coded by the PNPT1 gene, the protein is associated with mitochondrial homeostasis and functions as a possible target for cancer therapy. In this study, C. elegans was used to investigate the effect of mutation and overexpression of pnpt-1, the gene that encodes PNPase. It was determined that two specific mutations in pnpt-1 did not affect PNPase expression nor did they produce deleterious phenotypes that affected polycistronic transcript accumulation or ROS production. Creation of a stable overexpression model was achieved through Fusion PCR. However, different transgenic strains overexpressing PNPase produced opposite results for polycistronic transcript accumulation while ROS production saw no significant change, suggesting a mosaic overexpression model. In a cancer model, exogenous PNPase was present in the pachytene region of the germline and where expressed the cells were in non-germline cells suggesting differentiation mechanisms associated with overexpression of PNPase. However, further analysis of different mutations in pnpt-1 or optimizations to the overexpression model are necessary to provide a better understanding of PNPase function with mitochondria homeostasis and in a cancer model setting