The gene pam-1 encodes a puromycin-sensitive aminopeptidase that, in mutant form, causes several deleterious phenotypes in C. elegans, including lowered hatch rate and disturbed cytoskeletal and cortical activity around division. Mutation in the suppressor gene lz6 can partially rescue the associated phenotypes. In order to understand the interaction between pam-1 and its suppressor, we sought to determine the location of the suppressor within the genome using SNP mapping, to produce strains via crosses that will be useful in further analysis of this system, and to compare lz6’s suppressing effect on multiple alleles of mutant pam-1. Two candidate regions for lz6 were found on linkage group I, but further mapping is necessary to confirm the location. Two strains expressing lz6 suppression of the pam-1 allele or403 were created to compare phenotypically to worms expressing the lz6-suppressed or347 allele. Finally, results show no significant difference in suppression phenotypes between the or347 and or403 alleles of pam-1 for two markers around division (pseudocleavage and asymmetric division), suggesting the suppressor is not allele specific. This implies that suppression of PAM-1 does not depend on the protein’s functionality, lending credence to the hypothesis that suppressors are targets for PAM-1 degradation and mutation causes them to become nonfunctional. This study also suggests several approaches for further experimentation in this system.
Biochemistry and Molecular Biology
Rebecca Lyczak and Eric Williamsen