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In the nematode C. elegans, the first cell division corresponds with anterior-posterior axis formation. Polarity establishment prior to the first cell division is essential for correct separation of “head” and “tail” components. In C. elegans, this action follows two distinct but often redundant pathways of polarization. In this lab, we study wild-type worms, pam-1 mutants, and pam-1;lz4 mutants in order to examine these two polarity establishment pathways. PAM-1 is a puromycin-sensitive aminopeptidase, but when there exists a mutation in the pam-1 gene, a nonfunctional protein results. This mutation causes polarity establishment defects in the embryo and results in lethality in most cases. A secondary suppressor mutation, lz4, can partially or fully restore the polarity of a pam-1 embryo and lead to a lower lethality rate overall. Using specific polarity landmarks under confocal microscopy, polarity establishment can be compared in these strains. These observations may help indicate the mechanism of action of the suppressor lz4 and its rescue of the AP axis. In this study, it is shown that lz4 does not rescue pam-1 mutants through either of the aforementioned redundant pathways. Instead, it appears that lz4 acts on some downstream target to restore asymmetry of division and embryo survival rate. Once the mechanism of action is confirmed, it will provide great insight into the identity of the gene where lz4 is located.
Otto, Amanda, "Investigation of the Role of the lz4 Suppressor of pam-1 in Polarity Establishment in the Single-celled C. elegans Embryo" (2018). Biology Honors Papers. 25.